University of Kansas Publications

MUSEUM OF NATURAL HISTORY

VOLUME 3 · 1951

EDITORS

E. Raymond Hall, Chairman
A. Byron Leonard
Edward H. Taylor
Robert W. Wilson

Museum of Natural History
UNIVERSITY OF KANSAS
LAWRENCE 1951

Museum of Natural History
UNIVERSITY OF KANSAS
LAWRENCE

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1951

24-1811

[CONTENTS]

The Avifauna of Micronesia,
Its Origin, Evolution, and Distribution
BY
ROLLIN H. BAKER

University of Kansas Publications
Museum of Natural History
Volume 3, No. 1, pp. 1-359, 16 figures in text
June 12, 1951

University of Kansas
LAWRENCE
1951

The Avifauna of Micronesia,
Its Origin, Evolution, and Distribution
BY
ROLLIN H. BAKER

University of Kansas Publications
Museum of Natural History
Volume 3, No. 1, pp. 1-359, 16 figures in text
June 12, 1951

University of Kansas
LAWRENCE
1951

University of Kansas Publications, Museum of Natural History
Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
Edward H. Taylor, Robert W. Wilson

Volume 3, No. 1, pp. 1-359, 16 figures in text
Published June 12, 1951

University of Kansas
Lawrence, Kansas

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1951

24-1811

The Avifauna of Micronesia,
Its Origin, Evolution, and Distribution
By
ROLLIN H. BAKER

[CONTENTS]

[FIGURES IN TEXT]

[INTRODUCTION]

Birds in Micronesia comprise the most outstanding animal life of the islands, as far as vertebrates are concerned. No fewer than 206 kinds, belonging to 37 families and 91 genera have been found there. Although this number upon first consideration may seem large, actually any large land mass in the same latitude has many more kinds of birds than does Micronesia. In this connection it is pertinent to recall that the islands of Micronesia are oceanic and have apparently been formed independently of any continental land mass. Thus, animal life found on these islands has reached them by overseas migration, either by some passive means or by individual effort. Zoogeographers have had some difficulty in explaining the presence of snails and other nonflying animals on isolated oceanic islands. Crampton, in his studies of the land snails of the genus Partula at Guam and Saipan (1925:10), writes, "Despite the geological difficulties, the biological findings strongly support the view that the dominant process in this part of Oceania has been one of subsidence and of insular dissection." Although there exists today some question as to how certain forms of life have reached these remote dots of land, the ornithologist has not been much in doubt as to the actual means of arrival of birds. With the exception of six kinds of birds which are definitely known to have been introduced by man, the birds have apparently reached these islands by flying there from somewhere else. The ornithologist is, therefore, concerned with learning from where, by what route, when, and why the various species of birds came and how they have become established on these islands of Micronesia. These birds exist in small populations; often less than 100 individuals of one kind may be found on a small island. How have such small numbers had the ability to survive and what environmental adaptations have occurred, are two additional questions which confront the student of Micronesian birds.

[DESCRIPTION OF MICRONESIA]

The vast expanse of the Pacific Ocean is dotted with numerous islands, most of which are concentrated in the central and western part and are known collectively as Oceania. Within Oceania three divisions are popularly recognized: Melanesia, Polynesia, and Micronesia. According to Krieger (1943:6), the Micronesia islands include the Mariana, Palau, Caroline, Marshall, and Gilbert islands; they may take in also the Volcano, Bonin, and Ellice islands (from the standpoint of anthropology). Zoogeographically, according to Wallace (1876), Micronesia is to be included in the Polynesian Subregion of the Australian Region. Mayr (1941a:193), on the basis of the distribution of birds, ranks Micronesia as one of the four subdivisions of the Polynesian Subregion, and includes within Micronesia the Palau, Caroline, Mariana, Marshall, and Gilbert islands. Except in the discussion of distribution, this report does not treat of the avifauna of the Gilbert Islands, which straddle the equator south of the Marshall Islands. This report is concerned only with the birds in the Mariana, Palau, Caroline, and Marshall islands formerly mandated to Japan, and with the birds of the island of Guam, which is a possession of the United States.

Fig. 1. The Islands of Micronesia.

The word Micronesia is, of course, derived from the Greek words mikros meaning small and nesos meaning island, and, as shown in [figure 1] , this term is appropriate, for the islands of this area are small. For the most part they are too small even for inclusion on standard-sized maps of the world. There are thousands of these islands in an area some 2,400 miles long from east to west and some 1,200 miles broad from north to south. All of the islands of Micronesia are oceanic islands; that is to say, they have never been connected to the Asiatic continent or to other land masses by means of land bridges.

Geologists and oceanographers have shown (see descriptions by Hobbs, 1945), that islands of Micronesia are of two general types: arcuate and strewn. The Pacific Ocean is surrounded by rising mountain ranges which are arranged in elongated, near-circular arcs, which form an extended series of scallops. In the western Pacific these sweeping arcs extend into the ocean, where the mountain ranges project upward from the bottom of the sea with only the crests showing above the waves to point out, in dotted outline, the position of the mountains. The easternmost of these arcs is marked by the islands of the Aleutians, Kuriles, Japan, Izo, Bonins, Volcanoes, Marianas, Yap, Palaus, and others continuing southward into Melanesia. These are characterized by igneous rocks of andesitic nature.

To the eastward of the arcuate islands in Micronesia, are numerous and irregularly distributed islands, making up all of the central and eastern Carolines and the Marshalls, which are known as strewn islands. Strewn islands mark the places of former volcanoes or volcanic peaks. If these volcanic peaks have been completely drowned and are now marked by a series of low islands edged by a protecting reef formed by coral growth enclosing a lagoon and with all exposures consisting of coral rock, the island is known as a coral atoll (example, Ulithi Atoll). Some of the coral exposures lack lagoons; they are known merely as coral islands (example, East Fayu). Some atolls become elevated by geologic activity and the lagoons may dry out or drain. The accumulation of guano of oceanic birds and the residue of fish and other organisms in the area of the lagoon remains as a rich phosphate deposit; these raised atolls have been called phosphate islands (example, Fais). Other strewn islands consist of igneous rocks which are exposed above the surface of the ocean. These are known as "high" or volcanic islands and may occur as a single mountain rising out of the ocean (example, Kusaie), or be partly drowned and surrounded by a coral reef (example, Truk). The igneous rocks found on these strewn islands are basaltic in nature.

The Mariana Islands consist of a chain of volcanic islands approximately 450 miles long. As shown in [figure 2], there are 14 single islands and one group of three islands (Maug), from Uracas in the north to Guam in the south. The Palau Islands which are situated in the easternmost part of Micronesia have often been considered from a political standpoint as part of the Caroline Islands. As shown in [figure 3], the Palau Islands are a chain of islands approximately 120 miles long from north to south. Sonsorol, Tobi, Merir, Pulo Anna, and Helen Island occur to the southward of the Palaus and may be considered as part of the Carolines or as part of the Palaus. The Palaus together with the Carolines, to the eastward, extend in an east-west direction for approximately 1,700 miles. The Palaus and Carolines include (as shown in [figures 3] and [4]) 37 atolls, 34 banks, 11 coral islands without lagoons, 2 uplifted phosphate islands, 4 volcanic islands, and the Palau chain. The Marshall Islands to the extreme eastward extend approximately 700 miles from north to south and, as shown in [figure 5], contain 29 atolls and five coral islands without lagoons. No volcanic exposures occur in the Marshall Islands.

There is a total land surface of approximately 846 square miles in the islands of Micronesia. The Palaus and Carolines have 525 square miles, the Marianas 247 square miles, and the Marshalls 74 square miles of land surface. Guam has the largest land surface of any of the islands of Micronesia with 225 square miles, Ponapé has 145 square miles, and Babelthuap has 143 square miles. Asuncion, in the northern Marianas, has the highest elevation, rising as an almost perfect cone to a height of 2,923 feet; Ponapé reaches a height of 2,579 feet above the sea level. The volcanic islands are known as "high" islands, and the coral atolls are known as "low" islands. The coral islands usually rise but a few feet above sea level.

Climate

In Micronesia there are two seasons: a wet summer and a dryer winter. Temperatures rarely go above 90° F. and rarely below 70° F. Rainfall in the Marianas averages approximately 85 inches per year, in the Palaus approximately 150 inches, in the Carolines it ranges from 129 to 185 inches, and in the Marshalls it goes up to 160 inches. The humidity is excessive, the average annual mean of relative humidity for selected islands in Micronesia being between 82 and 86 percent. The relative humidity is lower in the western Carolines and the Palaus, than in other parts of Micronesia.

The Mariana Islands lie between the area of the Asiatic monsoon and the belt of the northeast trade winds. At Saipan from November until March or April, winds usually are easterly or northeasterly and are strong and steady since the northeast trades and the winter monsoon reinforce each other. In April and May the directions of the winds shift toward the southeast, and they become weaker and more variable. In this period there may be some easterly winds in addition to the predominating southeasterly winds. Detailed information is not available on the winds which occur in the Marianas north of Saipan, but at Pagan easterly winds probably prevail from May to July and westerly winds prevail in the remainder of the year. The Carolines lie in the belt of alternating northeast trade winds and southwest monsoons. The northeast trades begin in October and prevail until May or June. The southwest monsoon occurs from May to October and may be felt as far east as Truk. To the eastward, the winds of the summer are usually light and variable. In the Marshall Islands, the northeast trade winds predominate from about December to April, especially in the northern part of the Marshalls. In summer, winds are variable and weak; periods of calm may occur. Typhoons and squalls occur most frequently in the spring and summer in Micronesia. Some of the severe typhoons are known to engulf entire islands, as did the one at Woleai in 1907.

Soils

The soils of the islands of Micronesia have been derived from volcanic materials or from depositions of coralline limestone. Volcanic soils occur on the "high" islands of Micronesia. In many places, especially on the islands of the northern Marianas there is little soil; there are large areas of bare igneous rock, because the islands are geologically of relatively recent origin and little erosion has occurred. On islands where volcanic rocks have decomposed, the resulting soil may have a top layer of humus. The richest soils of the islands are along drainage areas and in alluvial deposits.

Coralline soils result from the decomposition of limestone, coral fragments, shells, and sand, and are overlain by some humus. Where the layer of humus is deep, the fertility is greatest. Coralline-volcanic soils occur on some "high" islands where coral rock and volcanic rock have become mixed in the decomposition process which forms soil. In parts of the Marianas and elsewhere, unwise practices of burning and overgrazing have allowed extensive erosion to occur, resulting in reduced fertility of the soil. On the island of Yap certain sedimentary rocks are exposed which are thought to have been elevated from the ocean bottom. Soils at Yap which have developed from this rock are considered more fertile than soils of coralline origin, although the fertility there also is dependent on the depth of the layer of humus.

Surface Water

There is little fresh water on the coral atolls, but brackish marshes are present on some islands, and many of these marshes are used for the cultivation of taro by the natives. Some volcanic islands, on the other hand, possess small streams and fresh water lakes, producing suitable habitat for certain rails, gallinules and ducks. On the "low" islands in the Marshalls, natural surface pools are rare.

Vegetation

The "high" islands of Micronesia support a heavy cover of vegetation. Typically the lowlands and stream courses are covered with dense jungle vegetation, and the slopes and higher hills are covered with grasses and brush. The vegetation of the "low" coral atolls and islands is, by comparison, much less dense. Many shorelines are covered with scant grasses and shrubs and the interior in many places is dominated by coconut, betel palms, breadfruit, papaya, and pandanus. References to papers dealing with plants in the islands of the Pacific may be obtained in Merrill (1945), who (1945:207) writes, "Botanically, the low islands are very uninteresting and monotonous. The flora of one is usually quite the same as that of another, although these islands and islets may be separated by many hundred and in some cases several thousand miles. The native vegetation may be scanty or reasonably well developed, depending on the size of the island, the quality of its soil, and whether or not it is permanently inhabitated." Of the vegetation on the "high" islands of the Pacific area, Merrill (1945:209) comments that the vegetation "is well developed, particularly within the forested areas, but for these high islands within the Pacific basin as a whole, the number of endemic genera is relatively small and most of them have definite relationships with those of Malaysia." Concerning the "high" islands of Micronesia, Merrill (1945:210) remarks that these islands are smaller and more isolated than some of the others in Oceania and have fewer individual species "as compared with what one finds on islands of a similar size located within limits of the Malay Archipelago. Thus with all of the islands under Japanese mandate, and including a number of high, but at the same time relatively small islands, less than 1,300 different species are known, of which 230 manifestly represent purposely or accidentally introduced ones. This relatively small flora includes representatives of approximately 620 genera in 192 families.... Specific endemism is relatively high, for approximately 460 species are confined to the islands within the area under consideration. The generic endemism is very low; about seven endemic genera only are involved for the whole group." The figures for endemism of plants are comparable to those for birds. Of endemic birds there are 5 genera, 35 species, and 73 subspecies. The total number of species of birds known from Micronesia is only 206 as compared with 1,300 plants. Yamada (1926:966) writes that the number of species of plants that Micronesia has in common with Japan may be due to the influence of the "Japan Stream."

Many land birds in Micronesia depend directly on the plant life for food. Possibly the soil (including its mineral content), upon which the plants themselves depend for development of fruits and other edible parts, may offer a limiting factor to the distribution of birds in Micronesia. Possibly the fruits and other edible parts of plants do not provide the necessary amounts of proteins, carbohydrates, minerals, vitamins, and other essential food items for species of plant-eating birds, which have not become established in Micronesia. Possibly some species of plant-eating birds have reached Micronesia but have failed to establish themselves because of some dietary deficiency caused by poverty of the soils on which the plants grow. If a comparison were made of soils and of the food values of fruits of plants in both the islands of Micronesia and similarly sized islands in the Malay region, a difference might be revealed which would partly explain why some plant-eating birds have not become established in Micronesia.

[GAZETTEER OF ISLANDS OF MICRONESIA]

In the following list the name in current usage for each island or island group in Micronesia is followed by other names which have been used. There is no attempt made to list the names of the small islands of each atoll or those of the myriads of small islets that lie offshore from the larger volcanic islands. Collections have not been made on most of the smaller islands. For the few on which a species has been collected, the islet is adequately described in the account of the particular species concerned. The reader may refer to Brigham (1900) for a listing of the islands of the Pacific Ocean. Most of the islands included in the following list may be located on the map of Micronesia as shown in [figures 2], [3], [4], and [5]. These listings follow in order of arrangement those in the Civil Affairs Handbooks, published by the United States Navy Department (1943, 1944a, 1944b, and 1944c).

Mariana Islands

The Mariana Islands (also called Ladrone, Marianne, Marian) consist of 14 single islands and one group of three islands. The Marianas are all "high" or volcanic islands. The islands, shown in [figure 2], are listed as follows:

Agrihan (also called Agrigan, Arijan, Francisco Xavier, Granger, Gregus, Grigan, San Francisco Javier).

Agiguan (also called Agaigan, Agiigan, Agiguan, Agigwan, Aguigan, Aguijan, Aguyan, Guigan, Saint Ange, Santa Angel).

Alamagan (also called Almagan, Aramagan, Concepcion).

Anatahan (also called Anatagen, Anatajen, Anataxan, San Joaquin).

Asuncion (also called Asonson, Assongsong, Assumption).

Guam (also called Guaham, Guahan).

Guguan (also called Guguwan, Guugwan, Piedras, San Felipe, St. Philippe).

Maug (also called Mang, Mangs, Mauga, Monjas, Mougu, Saint Laurent, San Lorenzo, Tunas).

Medinilla (also called Bade, Bird, Farallon de Medinilla, Rocher).

Pagan (also called Pagon, Paygan, St. Ignace, San Ignacio).

Rota (also called Luta, St. Anne, Santa Ana, Sarpan, Satpana, Suta, Zarpane).

Saipan (also called (Saepan, St. Joseph, San José, Saypan, Siepan, Serpan, Seypan).

Sarigan (also called St. Charles, San Carlos, Sariguan, Sarigwan).

Tinian (also called Bona Vista, Buenavista, Temean, Tenian, Tiniamou).

Uracas (also called Guy Rock, Farallon de Pájaros, Pájaros, Urakasu).

Fig. 2. The Mariana Islands.

Palau Islands

Fig. 3. The Palau Islands.

The Palau Islands (also called Arrecifos, Palaos, Paleu, Pally, Paloc, Pannog, Parao, Pelew) consist of 8 large islands, 18 smaller islands, and a large number of minute islets, all enclosed in a single reef system. The northern islands (Babelthuap and Koror) are of volcanic origin; the southern islands (Peleliu and others) are of coralline formation. Angaur, to the south of Peleliu, may be included with the Palau Archipelago. From the standpoint of the avian zoogeography, the coral islands or atolls of Kayangel, Merir, Pulo Anna, Sonsorol, and Tobi are also included. The principal islands, shown in [figure 3], are listed below:

Arakabesan (also called Ngarekobasang).

Aurapushekaru (also called Aburashokoru, Auluptagel, Oluksakel, Oropu-shakaru).

Babelthuap (also called Babeldzuap, Babel Taob, Babelthouap, Baberthaob, Baberudaobu, Babldaob).

Eil Malk (also called Amototi, Cogeal, Irakong, Makarakaru).

Garakayo

Koror (also called Coror, Goreor, Kororu).

Malakal (also called Amalakell, Malaccan, Marakaru, Nanalake).

Ngabad

Ngesebus (also called Guadokusu).

Peleliu (also called Pelelew, Periryu, Pililer, Peliliu, Uler).

Urukthapel (also called Cape, Kuapasungasu, Ngurukdapel, Ulugeang, Uruk-taaburu, Uruktapi).

Included with the Palau group because of proximity and relationships of the avifauna are the following:

Angaur (also called Angauru, Angyaur, Ngaur, Ngeour, N'Yaur).

Kayangel (also called Kadjangle, Kajanguru, Kazyanguru, Kianguel, Kreiangel, Moore, Ngajangel, Ngeiangel).

Merir (also called Marir, Meliel, Meriel, Meriru, Pulo Marier, Warren Hastings).

Pulo Anna (also called Anna, Bul, Bur, Current, Paola, Pul, Puru, Wull).

Sonsorol (also called St. Andrew, San Andreas, Sonesor, Songosor, Sonseron, Sonsol, Sonsoru, Tschontil).

Tobi (also called Codopuei, Johnstone, Kadogubi, Lectobis, Lord North, Nevil, Togobei, Tokobei).

Caroline Islands

The Caroline Islands consist of 41 island clusters or isolated islands (exclusive of submerged coral reefs). These are of coral formation. They are atolls or single islands except for Yap, which is of sedimentary rock, and Kusaie, Ponapé, and Truk, which are of volcanic rock. The principal islands are shown in [figure 4] and are listed as follows:

East Fayu (also called Fajo, Faliao, Lutké, Rukutee).

Eauripik (also called Aurepik, Eourpyg, Iuripik, Kama, Low, Yorupikku, Yuripik).

Fais (also called Astrolabe, Feis, Feys, Fuhaesu, Huhaesu, Tromelin, Woaje).

Faraulep (also called Faraulip, Faroilap, Fattoilap, Foroilap, Furaarappu, Gardner, Huraarappu).

Ifalik (also called Evalook, Faloc, Furukku, Hurukku, Ifalouk, Ifelug, Two Sisters, Wilson).

Kapingamarangi (also called Bakiramarang, Constantine, Greenwich, Guriinitchi, Kabeneylon, Kapenmailang, Makarama, Pikiram, Tenuv).

Kusaie (also called Arao, Armstrong, Experiment, Hope, Kusai, Kuschai, Kushai, Kuthiu, Oualan, Quollen, Strong, Teyoa, Ualan, Walang).

Lamotrek (also called Lamorsu, Lamureck, Lamutrik, Low, Namotik, Namotikku, Manochikku, Namurrek, Swede).

Lukunor (also called Lemarafat, Lougoullos, Lougounor, Luganor, Lugunor, Lugunoz, Mortlock, Namonefeng, Rukunoru, Youngwilliam).

Namonuito (also called Anonyma, Baxos de San Bartolomeo, Bunkey, Las Hermanas, Livingstone, Lost Jardines, Lutké, Namenwita, Olol, Omun, Onon, Ororu, Remp, Ueito, Ulul).

Ngulu (also called Angegul, Anolul, Goulou, Kurru, Lamoliao, Lamoliork, Lamuliur, Lamuniur, Matelotas, Ngilu, Ngoli, Ngolog, Spencer Keys, Ulu).

Nukuoro (also called Dunkin, Matakema, Menteverde, Nugoru, Nukor, Nukuor).

Pikelot (also called Bigali, Biguela, Coquille, Lydia, Pigela, Pigerotto, Pigouelao, Pik, Pyghella).

Pingelap (also called Macaskill, Musgrave, Pelelap, Piigerappu, Punlap, Sailrocks, Tucks Reef).

Ponapé (also called Ascension, Bonabee, Bonybay, Faloupet, Faounoupei, Funopet, Niponpei, Painipete, Ponapi, Piunipet, Puynipet, Quirosa, Seniavin, William IV). Ponapé is the largest island of the Senyavin Islands.

Truk (also called Djuk, Hogoleu, Hogolu, Hoguleu, Lugulus, Ola, Rough, Ruck, Ruk, Torakku, Tuck, Ugulut). The Truk group includes approximately 100 islands.

Ulithi (also called Mackenzie, Mogmog, Mogumogu, Mokomok, Ouluthy, Uluthi, Uluti, Urushi).

West Fayu (also called Faiyao, Fajahu, Faliau, Huiyao, West Faiu).

Woleai (also called Anagai, Mereyon, Oleai, Ouleyai, Thirteen Islands, Uala, Ulea, Uola, Ulie, Wolea).

Yap (also called Eap, Guap, Heap, Jap, Ouap, Uap, Wuap, Yappu).

Fig. 4. The Caroline Islands.

Marshall Islands

The Marshall Islands consist of 29 atolls and 5 coral islands without lagoons arranged in two chains, the Ralik and the Radak chains, which extend in a northwesterly to southeasterly direction. No volcanic rocks are exposed in these islands. The principal islands shown in [figure 5] are as follows:

Ailuk (also called Ailu, Fisher, Krusenstern, Tindall, Watts).

Arhno (also called Arno, Aruno, Auru).

Bikar

Bikini

Ebon (also called Boston Atoll).

Elmore (also called Ailinglap, Ailinglapalap, Iringlob).

Eniwetok

Jaluit (also called Bonham, Taluit).

Kwajalein

Likieb (also called Likiep).

Majuro (also called Arrowsmith, Mezyuro).

Mejit

Maloelab

Mille (also called Mulgrave).

Namorik

Namu (also called Musquillo, Namo).

Rongelap

Wotje (also called Romanzov, Wotze, Wozzie).

Fig. 5. The Marshall Islands.

[ORNITHOLOGICAL EXPLORATION IN MICRONESIA]

The Micronesian islands were first explored and colonized by a a people who came from Malaysia. It is thought that these people spread into the Palau, Caroline, Mariana, Marshall, and Gilbert islands as a single wave of migration. Following this occupation, the people apparently underwent a normal process of cultural evolution and differentiation. Remains of stone walls, dikes, fences, pillars, graves, and other structures which may be found today at various islands in Micronesia were constructed by the ancestors of the islanders of the present day. It is thought by archeologists that the Polynesians moved eastward into the Pacific islands by way of Micronesia. The date of this wave of migration is thought to have been approximately 1200 A. D. What kinds of birds may have been exterminated by this earliest of human colonization cannot be ascertained. Edible species, particularly megapodes, rails, and pigeons, probably were eliminated or reduced in numbers, as is indicated by later discussions.

The first Europeans to visit Micronesia, as far as the present writer can ascertain, left no accounts of the birds significant for the study here reported upon. Magellan, on his trip around the world, was the leader of the first party of Europeans who touched at Guam; this was on March 6, 1521. Rota, Agiguan, Saipan, and Tinian were also discovered by this Portuguese sea captain in the service of the king of Spain. Eltano, one of Magellan's lieutenants, revisited the Pacific and stopped at Rota in 1524. After the voyage of Magellan, other seafarers, mostly in the service of Spain, visited the Micronesian islands. The Caroline Islands were apparently first observed by the Portuguese captain, Diego de Rocha, in 1526. Loyasa and Saavdera, both Spaniards, visited the Marshall Islands in 1526 and 1529, respectively.

One of the first travelers to record observations on the bird life was Henry Wilson. Wilson was captain of the schooner "Antelope" which became grounded on a reef in the Palau Islands in August, 1783. He lived with the islanders while the ship was being repaired and kept a journal of his observations (Wilson, 1788). Wilson also visited several other islands in western Micronesia. Adelbert von Chamisso (1821), as naturalist with the Russian expedition in the ship "Rurick," made observations of the animal life in Micronesia in 1817 and 1818. Under the command of Otto von Kotzebue, this Russian expedition made the first detailed exploration of the Marshall Islands; visits were made also to Guam and Rota and to Yap, Fais, Ulithi, Palau, and other island groups in western Micronesia. Freycinet's famous expedition in the ships "Uranie" and "Physicienne," visited Guam, Rota, and Tinian in 1819. Quoy and Gaimard, the naturalists of the expedition, obtained birds, which were among the first to be described from Micronesia. These two naturalists revisited the Marianas in 1829 on board the ship "Astrolabe." Scientific results of both of these expeditions (Quoy and Gaimard, 1824-'26 and 1830-'35) include texts and plates dealing with the birds obtained.

The French expedition in the corvette "La Coquille" visited Kusaie in June, 1824. Lesson (1829) wrote the zoology of this trip. Kittlitz (1836) of the expedition which sailed in the corvette "Le Seniavine" commanded by Lutké obtained birds at Kusaie in December and January, 1827-'28, at Guam in March, 1828, and at Lukunor and other islands of the Carolines. At Kusaie, Kittlitz found a rail (Aphanolimnas monasa) and a starling (Aplonis corvinus) which have not been obtained since his time. His specimens were deposited in St. Petersburg. He was one of the most competent of the early naturalists; his writings contain accounts of habits as well as descriptions and are accompanied by colored plates. The expedition which sailed on the "Astrolabe" and the "Zélée" in 1827-'40 under the command of Dumont d'Urville visited the Caroline Islands. The naturalists, Hombron and Jacquinot, obtained birds at Truk, including the interesting flycatcher, Metabolus rugensis, which they described (1841). The "Novara," in the course of its voyage around the world (1857-'59) visited the Caroline Islands in 1858. Birds were recorded from Ponapé, Lukunor and other islands by Pelzeln in his account of the birds of the expedition (1865).

In the years following the middle of the Nineteenth Century, Godeffroy and Sons, of Hamburg, opened branches of its trading firm in Micronesia. Representatives of the company including Heinsohn and Peters, who were ship captains, obtained collections of birds at Palau and Yap. These were deposited in the Godeffroy Museum at Hamburg and reported on by Hartlaub and Finsch (Hartlaub, 1868; Hartlaub and Finsch, 1868a and 1872). Tetens became representative of Godeffroy and Sons at Yap in 1869 and obtained birds. Perhaps the most famous collector in this period was Johann Kubary. He went to Ponapé at the age of nineteen and traveled in Micronesia for many years for Godeffroy and Sons. He obtained birds at many of the islands of the Carolines, spending fourteen months at Truk. In 1873, one of his collections of some 200 birds was lost in a shipwreck. Hartlaub and Finsch, (Hartlaub and Finsch, 1872; Finsch, 1876a) described much of his material; Nehrkorn (1879) reported on nests and eggs which he obtained. Hartlaub and Finsch (1868b) also reported on birds obtained at Palau by Doctor Semper, which were deposited in the museum at Altona. Otto Finsch (1880b, 1880d, 1881b, 1881c) traveled in Micronesia about 1880, observing birds in the eastern Carolines and in the Marshalls.

One of the largest collections from Micronesia was made by Alfred Marche in the Marianas. He arrived there on April 22, 1887, and stayed until May, 1889. He obtained approximately 732 specimens of birds, nests, and eggs at Guam, Rota, Tinian, Saipan, Pagan, and Alamagan, which were deposited in the Paris Museum and reported on by Oustalet (1895-'96). Shortly after Marche's visit, Japanese collectors in the hire of Alan Owston, a professional collector of Yokahama, obtained birds in the Marianas and at Truk in the years 1894-'97. These went to the Rothschild collection at Tring and were reported on by Hartert in 1898 and 1900.

At the turn of the Twentieth Century, several ornithologists were visiting Micronesia. Alvin Seale (1901) obtained a collection of birds at Guam in the summer of 1900 which was deposited in the Bernice P. Bishop Museum in Honolulu. The U. S. Fish Commission steamer "Albatross" visited Micronesia from August, 1899, to March, 1900; birds obtained by the expedition were reported on by Townsend and Wetmore (1919). Paul Schnee (1901) spent approximately one year, 1899-1900, at Jaluit in the Marshalls and obtained records of birds. In 1899, Brandeis, on board the German ship "Kaiserland" visited many of the islands in the Marshalls and recorded birds. William Safford (1905) resided at Guam in the early part of this century and reported on the bird life in the course of his studies of the botany and native life. Bartsch (Mearns, 1909) also obtained a small collection of birds at Guam, this is in the United States National Museum.

In the first World War when the Japanese gained a mandated control over the islands of Micronesia, the Japanese ornithologists promptly visited the area, obtained collections, and published works concerning the birds. In 1922, Momiyama and Kuroda prepared a list of the birds of Micronesia. The work was published under the auspices of the Ornithological Society of Japan. Subsequent editions appeared in 1932 and 1942.

The Whitney South Sea Expedition of the American Museum of Natural History visited Micronesia from October, 1930, to December, 1931, with William F. Coultas as collector. Although experiencing some difficulty and being restricted somewhat in his travels by the Japanese officials, he managed to obtain collections at Ponapé (October 26, 1930, to January 1, 1931), Kusaie (January 15 to June 11, 1931), Guam (June 24 to August 30, 1931), Saipan and Tinian (September 1 to 26, 1931), and Palau (October 2 to December, 1931). Many of the species which he obtained are represented by large series of fine skins. Only part of his collections have been reported on by Mayr and his associates.

Other than the work of Coultas and that of the Japanese, there was little ornithological work done in the period between the two world wars, probably, at least in part, because of the "iron curtain," which Japan had thrown about her mandate. Bryan (1936) did visit Guam in the middle 1930's and published an account of the birds in the newspaper, Guam Recorder.

When the Micronesian islands were taken by the American forces in 1944, personnel attached to various units made observations on the bird life. The first reports, published or unpublished, were from the Marshalls, which were taken at the beginning of the campaign. Gleise, Genelly, Wallace, and others made contributions. In the Marianas considerably more observing and collecting were done by service personnel including Marshall, Stott, Borror, Strophlet, Buss, Watson, Arvey, Downs, and others. Marshall (1949) obtained also a collection of birds in the Palaus in 1945. The Laboratory of Mammalogy, United States Naval Medical Research No. 2, to which I was attached, collected at Guam (January to October, 1945), at Rota (October 17 to November 2, 1945), at Ulithi (August 11 to 23, 1945), at Palau (August 24 to September 24, 1945), and at Truk (November 24 to December 18, 1945). Following the end of the war, Harvey I. Fisher visited Micronesia and obtained a collection of birds at Yap, which is to be reported on in the near future. Larry P. Richards obtained 33 birds at Ponapé and 4 at Truk in the period from August 28, 1947, to February 10, 1948.

Descriptions of birds in Micronesia began with the naming of Halcyon c. cinnamomina in 1821; the most recent description is that of Rhipidura rufifrons mariae in 1946. In all, 131 descriptions have designated type localities in Micronesia. [Table 1] lists the dates (on the basis of ten-year intervals) when names of birds (synonyms or otherwise) were proposed. In the period from 1821 to 1860, twenty-five birds were made known to science by the earliest workers, including Kittlitz, Lesson, Bonaparte, and Pelzeln. In the period from 1861 to 1880, thirty-four birds were newly named, mostly by Hartlaub and Finsch, from the collections which the Godeffroy Museum obtained through the efforts of Kubary, Tetens, Peters, and Heinsohn. Nineteen original descriptions were published from 1881 to 1900, principally by Oustalet and Hartert, who studied the material of Marche and Owston, respectively. From 1901 to 1910, only four birds were described, but from 1911 to 1940, forty-seven descriptions were published, mostly by the Japanese following World War I. From 1931 to 1940, the number of known birds was increased by the efforts of Mayr, who studied the material of the Whitney South Sea Expedition. From 1941 to date only two original descriptions have appeared—only one was postwar. Except for possible undescribed subspecies in the northern Marianas, I think that the heyday of the taxonomist in ornithology in Micronesia is over. The field of avian ecology in Micronesia has barely been scratched.

Table 1. Compilation of the Dates (on the Basis of Ten-year Intervals) When Original Descriptions of Birds of Micronesia Appeared.

Table 1. Compilation of the Dates (on the Basis of Ten-year Intervals) When Original Descriptions of Birds of Micronesia Appeared.

[CHECK-LIST OF THE BIRDS OF MICRONESIA]

The 206 kinds of birds of 150 full species known to occur in Micronesia belong to 91 genera of 37 families of 13 orders. In the following list, nonresident birds are marked with an *; birds introduced by man are marked with a ^[+].

DISCUSSION OF THE BIRDS OF MICRONESIA

Of the 206 kinds of birds found in Micronesia, 30 kinds are classed as sea birds, 29 kinds as migratory shore birds, and 147 kinds are classed as land and fresh-water birds. For purposes of discussion these birds are arranged in these three categories, following the system used by Mayr (1945a).

Oceanic Birds

Oceanic birds found in Micronesia belong to the following families: Diomedeidae, Procellariidae, Phaëthontidae, Pelecanidae, Fregatidae, and Laridae. Following Wynne-Edwards (1935:240) and Murphy (1936:326), these birds may be grouped as inshore birds (Laridae and others), offshore birds (Pelecanidae, Fregatidae and others), and pelagic birds (Diomedeidae, Procellariidae, Phaëthontidae). As shown in [table 2] there are 30 kinds of oceanic birds in Micronesia, 18 kinds that are resident and 12 kinds that are regarded as visitors to the area. Records of nestings are few; field work in the future probably will yield evidence that more kinds of oceanic birds are actually resident in the Micronesian islands.

Table 2. List of Resident and Nonresident Oceanic Birds of Micronesia

Table 2. List of Resident and Nonresident Oceanic Birds of Micronesia

Inshore Oceanic Birds

The inshore zone, according to Wynne-Edwards (1935:240), "extends from high-water mark to a maximum of four or five miles out to sea, including islands and reefs within sight of shore." In Micronesia the majority of the Laridae occur in this zone including such residents as Sterna sumatrana, S. anaetheta, Thalasseus bergii, Anoüs stolidus, A. tenuirostris, Gygis alba. These birds, especially S. anaetheta, Thalasseus, and Anoüs, may venture into the offshore zone. Visitors to Micronesia include several terns which probably normally range in the inshore (as well as in offshore) zones, such as Childonias leucopterus and Sterna hirundo. These birds feed to a considerable extent inside the outer reefs surrounding the lagoons, coming to shore frequently in small or large groups. Gygis alba probably spends considerable time on shore; stomachs examined contained fish, crustaceans and insects, indicating that they obtain some of their food ashore.

Offshore and Pelagic Oceanic Birds

Wynne-Edwards (1935:241) defines the offshore zone as extending to the continental edge; however, in Micronesia where small islands rise abruptly out of the ocean's depths, there is no useful way to separate the offshore zone from the pelagic zone. Since certain species go farther from the land than others, the two zones may be combined as a single zone extending beyond the sight of land. Birds which frequent this area beyond the inshore zone but may not range extensively at sea include Fregata, Sula, Sterna fuscata, S. hirundo, S. anaetheta, and others. The Herring Gull (Larus argentatus), which has been taken in the northern Marianas, may be classed with this group although it probably ranges widely in the open sea. Birds which spend considerable time at sea and may seldom approach land include Diomedea nigripes, the petrels (Puffinus and Pterodroma), and possibly the tropic birds (Phaëthon).

In numbers of individuals the birds inhabiting the inshore zones are relatively more numerous than those preferring the offshore and pelagic zones, although 12 of the 18 resident kinds of oceanic birds apparently prefer the offshore zone, while only 6 kinds appear to be restricted primarily to the inshore areas.

Faunal Components

The oceanic birds were probably among the earliest birds to reach the islands of Micronesia. The presence of phosphate deposits on islands (Fais, Angaur), denoting deposition of guano by oceanic birds (possibly boobies, noddies, sooty terns), indicates long time residence by these birds. A person is prone to think that these deposits must have been made by larger concentrations of oceanic birds than are found in these islands today. Whether there were actually more individuals present during the period of deposition of phosphate in the lagoons of these islands is not known, although the elevation of the lagoons (forming the raised islands of Fais and Angaur) with the resulting freshening of the water probably was a great attraction to oceanic birds, especially to those which prefer to drink fresh water. According to Leonard P. Schultz (in litt.), the abundance of fish in the areas about these Pacific islands has been approximately the same since Pleistocene times, so that there was apparently no greater concentration of fish near these islands to attract large populations of fish-eating sea birds. Probably the time element is of sufficient magnitude to account for such deposition by birds with a population similar to that found there today.

The oceanic avifauna of Micronesia contains birds which are apparently from ancestral homes in the Palearctic Region, in the North and Central Pacific, in Polynesia, in Melanesia and Malaysia, and from homes the positions of which are uncertain because of the widespread circumtropical occurrence of the birds. There are no sea birds that are endemic in Micronesia.

Oceanic birds whose range is in the Northern Hemisphere (especially Palearctica) reach the northern and western edges of Micronesia as winter visitors. These include Larus argentatus, Chlidonias leucopterus, and Sterna hirundo. Another northern gull, Larus ridibundus, has been reported in the Marianas.

One bird of the North and Northcentral Pacific, Diomedea nigripes, reaches the northern Marianas where it has been taken at Agrihan. It is not unlikely that other birds of the North Pacific reach northern Micronesia as occasional visitors.

Species of oceanic birds which are restricted in their distribution to Polynesia and some adjacent islands and which range to Micronesia, either as visitors or residents, include Puffinus tenuirostris, P. nativitatis, Pterodroma rostrata, P. hypoleuca, Sterna lunata, and Procelsterna cerulea. The islands of the vast Pacific basin offer havens for many kinds of oceanic birds. Apparently there has been considerable speciation among sea birds in Polynesia, especially in its marginal areas. Micronesia has received only a small part of this avifauna.

Two terns, Sterna sumatrana and Thalasseus bergii, have reached Micronesia, either directly or indirectly, each from a dispersion point somewhere in the Melanesian or the Malayan area. These two birds are restricted in their ranges to the western Pacific and the Indian oceans.

Many of the species of oceanic birds found in Micronesia have circumtropical ranges. These include Puffinus pacificus, P. lherminieri, Phaëthon, Sula, Fregata, Sterna anaethetus, S. fuscata, Anoüs stolidus, A. tenuirostris, and Gygis alba. Some of these kinds range along continental shores as well as in island archipelagoes. Others, like Gygis alba, are rarely found along the shores of continents or even at coastal islands.

Migratory Shore Birds

Twenty-eight species of shore birds of the families Charadriidae and Scolopacidae have been recorded from Micronesia, and one other of the family Phalaropodidae apparently occurs in the area, making a total of 29 kinds. From the entire Southwest Pacific, Mayr (1945a:28-47) lists 31 species and subspecies of shore birds and mentions six other species which may occur there. Thus, of a possible 37 kinds of shore birds in this large area (which includes Micronesia), 29 are present in the islands of Micronesia. For purposes of discussion, shore birds are here placed in one of two groups: regular visitors or uncommon visitors. A regular visitor is one which has been recorded in the literature or in unpublished field accounts as being frequently observed in Micronesia in periods of migration. An uncommon visitor is one which has been infrequently observed in Micronesia. Of the 28 kinds of shore birds recorded from Micronesia, 17 are classed as regular visitors and 11 are classed as uncommon visitors.

Original Homes of the Shore Birds that Visit Micronesia

Table 3. Breeding and Wintering Grounds of the Species of Migratory Shore Birds in Micronesia

Part A. Location of breeding grounds

Table 3. Breeding and Wintering Grounds of the Species of Migratory Shore Birds in Micronesia

Part A. Location of breeding grounds

Part B. Location of wintering grounds

Part B. Location of wintering grounds

^[A] Denotes birds which breed on both American and Asiatic sides of the Pacific Ocean.

The shore birds which are known to visit Micronesia breed in the Northern Hemisphere. [Table 3] summarizes the data concerning the breeding and wintering areas of these birds. As shown in part A of [table 3], 18 of the 28 species which visit Micronesia come from Asiatic breeding grounds. Seven have circumpolar breeding ranges and three (two are regular visitors) come from American breeding grounds. As shown in part B of table 3, 21 of the 28 waders have their winter ranges on the Asiatic side of the Pacific with eastern extensions to Micronesia and other parts of Oceania. Of the 7 remaining species, the winter ranges of three are circumtropical; the winter range of a fourth is restricted to Oceania; and the winter ranges of the remaining three (two classed as uncommon visitors) are American.

Bryan and Greenway (1944:109-115) record 14 species of shore birds from the Hawaiian Islands. One of these, Himantopus himantopus knudsoni, is a resident, probably of New World origin, according to Mayr (1943:56). The others, listed in [table 7], include three species unknown in Micronesia. One of these, Phalaropus fulicarus, apparently winters at sea off the west coast of South America. The other two species (Charadrius vociferus vociferus and Gallinago delicata) are classified by Bryan and Greenway as "accidental" and "occasional" visitors from North America. The ten species common to both the Hawaiian Islands and Micronesia include seven whose breeding grounds are circumpolar, two whose breeding grounds are in Arctic America and one whose breeding ground is in Arctic Asia. The winter ranges of these ten species include four which are circumtropical, three which are Asiatic, one which is restricted to Oceania, and only two which are American.

The ability of the shore birds to migrate almost as well over water as over land may explain their spread into Oceania. The likelihood that shore birds, when migrating may have ventured to Micronesia and Polynesia initially from the Asiatic side of the Pacific is strongly suggested by the data given in the paragraph above. Also, on the Asiatic side of the Pacific there are large numbers of islands, which form several archipelagoes extending from Kamchatka south to Malaysia. Once accustomed to migrating along these chains of islands from the Arctic to Australia, birds would probably have to make only minor adjustments to extend the breadth of their migratory routes eastward into the islands of the Pacific Ocean. In contrast, on the Pacific coast of North America there are few coastal or offshore islands and there is a vast area of open water separating the Hawaiian Islands from the American mainland. Probably the vastness of this area of water offers little stimulus to birds to expand their migratory ranges westward, and in part accounts for the small North American contingent in the population of shore birds of the Central Pacific. Some North American shore birds do visit the Pacific. The brisk trade winds from the northeast might be an aid to the birds in their flights from Nearctica to Hawaii.

The long flight now made by shore birds going from the Aleutians to the Hawaiian Islands may have commenced as a gradual expansion from the west, or perhaps such a route was initiated by birds flying northward through the Hawaiian Chain to the Arctic in migrating to their breeding grounds, and then later returning via the same route to reach their wintering grounds.

Routes of Migration

Fig. 6. Routes of migration used by shore birds in the Pacific area. From west to east these are: The Asiatic-Palauan Flyway, the Japanese-Marianan Flyway, the Nearctic-Hawaiian Flyway.

The small and isolated islands of Oceania might, upon first inspection, seem to offer but little attraction to shore birds. Hesse, Allee and Schmidt (1937:172, 173) point out that the "open southeastern Pacific" being least supplied with water from land sources, which is an important means of fertility, is known to have one of the poorest faunas found anywhere in the oceans. However, there are extensive tidal flats, especially on the leeward sides of the islands, and these flats apparently afford extensive feeding grounds for these birds. Also, the absence of competition from resident birds as well as the virtual absence of predatory animals (native man and his domesticated animals excepted) are other factors which may help to make the islands attractive wintering grounds for shore birds.

Only a few birds have been banded in the Pacific, and the knowledge which comes from the recovery of banded birds gives but little aid to the student of movements of birds in the Pacific. The probable flyways for migratory shore birds there have to be deduced from sight records, data from specimens collected, known stations of breeding and wintering (summarized by Peters, 1934:234-293), and from a study of maps of the region. Analysis of information from the above-mentioned sources indicates that there are three routes taken by shore birds which migrate from Micronesia to and from their northern breeding grounds (see [figure 6]): (1) Asiatic-Palauan Flyway; (2) Japanese-Marianan Flyway; (3) Nearctic-Hawaiian Flyway.

1. Asiatic-Palauan Flyway. For shore birds, there appears to be a migration route extending almost due south from the Riu Kiu and the Japanese islands to the Palau Islands. Some birds may migrate via the Philippines and others may pass to the east of the Philippines. This route is considered to be distinct from that used by birds which follow the Asiatic Coast and coastal islands, because the Palau Islands are situated approximately 600 miles east of the Philippines. Moreover, there are fewer species—only 20 recorded from the Palaus as compared with the number recorded from islands closer to the mainland of Asia. Delacour and Mayr (1946:68-74) list 46 species of shore birds from the Philippines; the Hand-list of Japanese Birds (Hachisuka et al, 1942) lists 34 species from the Riu Kiu Islands.

The information available indicates that migrant shore birds which utilize this flyway move east into the Carolines (examples, Tringa nebularia, Charadrius leschenaultii); however, the recording of 20 species from the Palaus as compared with only 12 species in the western Carolines ([table 4]) indicates that this spread eastward may not be very pronounced. Migrants in autumn probably move from the Palaus in a southerly direction toward the New Guinea area. Eight species of shore birds which reach the Palaus (and adjacent islands in the western Carolines), are not recorded from other parts of Micronesia. Species which apparently utilize the Asiatic-Palauan Flyway are listed in [table 5].

2. Japanese-Marianan Flyway. Shore birds from Asiatic, and probably Aleutian and Alaskan, breeding grounds may follow the Asiatic Coast or the adjacent island chains southeast to the Japanese Archipelago. From there some of the birds apparently fly south through the Bonin and Volcano islands to the Marianas, from where they may spread in fanlike fashion to the southeast, south and southwest, even reaching to the Palau Islands (example, Heteroscelus incanus). The number of species of shore birds recorded from the Marianas (see [table 4]) is greater than that found in the Carolines, but it must be remembered that more intensive investigations have been made by ornithologists in the Marianas, which might account for the recording of more species (especially stragglers, such as Gallinago gallinago). Species which apparently use this flyway are named in [table 6].

3. Nearctic-Hawaiian Flyway. Shore birds from breeding grounds in western Canada, Alaska, the Aleutians, the Bering Sea area, and probably northeastern Asia may fly in a southerly direction along a broad front to the Hawaiian Islands. This flyway is probably the one which supplies to central and eastern Oceania the largest wintering populations of shore birds. From the Hawaiian Islands birds may fly directly south through the scattered islands to southern Polynesia, or they may fly in a southwesterly direction and reach the Marshall Islands. The shore birds which visit the Marshall Islands apparently move south through the Gilbert, Ellice and other more southern island groups rather than west into the Carolines as exemplified by the fact that Numenius tahitiensis, a characteristic migrant through the Marshalls from the Hawaiian Islands, is rarely found west of the Marshall Islands in Micronesia. Species which apparently use this flyway are listed in [table 7].

Flyways additional to the three suggested above may be utilized by some shore birds on their southward (and northward) migrations. Species reaching Wake and the Marcus Islands may fly directly south from the islands of the North Pacific. Bryan (1903:115, 116) lists four species of shore birds from Marcus (Erolia acuminata, Heteroscelus incanus, Pluvialis dominica, Arenaria interpres).

Table 4. List of Species of Shore Birds Known From Five Geographical Areas of Micronesia

Table 4. List of Species of Shore Birds Known From Five Geographical Areas of Micronesia

Table 5. Shore Birds Which May Use the Asiatic-Palauan Flyway

Table 5. Shore Birds Which May Use the Asiatic-Palauan Flyway

Table 6. Shore Birds Which May Use the Japanese-Marianan Flyway

Table 6. Shore Birds Which May Use the Japanese-Marianan Flyway

Table 7. Shore Birds Which May Use the Nearctic-Hawaiian Flyway

Table 7. Shore Birds Which May Use the Nearctic-Hawaiian Flyway

^* Indicates species which are found in Micronesia.

^[+] Indicates species not recorded from the Hawaiian Islands; see Bryan and Greenway (1944:109-115).

^* Indicates species which are found in Micronesia.

^[+] Indicates species not recorded from the Hawaiian Islands; see Bryan and Greenway (1944:109-115).

Populations of Shore Birds in Micronesia

Although shore birds have been observed in Micronesia on many occasions, actual counts of numbers of individuals of the different birds have rarely been made. Kubary, Finsch, Marche, Seale and other early collectors and observers record some data of this kind as have the Japanese investigators in later times. William Coultas of the Whitney South Sea Expedition obtained considerable information of this nature at Guam, Saipan, Kusiae, Ponapé, and the Palaus, but it is unpublished. His records were made in fall, winter and spring, when migrants were present in large numbers and these observations offer evidence that many of the migrants are comparatively numerous, especially in the Carolines, throughout the winter months. McElroy's observations made on his trip for NAMRU2 to Truk in December, 1945, offer further evidence of this.

Table 8. Populations of Migratory Shore Birds Seen at Guam in 1945

Table 8. Populations of Migratory Shore Birds Seen at Guam in 1945

^* Observations made on beach at Agfayan Bay area.

x Observed but numbers not recorded.

^[+] Figures based on identified skins.

^* Observations made on beach at Agfayan Bay area.

x Observed but numbers not recorded.

^[+] Figures based on identified skins.

None of the above workers, however, obtained very much information on comparative numbers of species.

Tables [8], [9], and [10] present the writer's findings on populations of migratory shore birds in Micronesia in 1945. At Guam, as shown in [table 8], the records for March, April and early May are few, owing to a limited amount of field observation. Beginning in late May and until October 24 a greater amount of time was spent in the field and more regular records were obtained. No observations were made by the author at Guam in the period from August 11 to September 25. The dates marked with an asterisk are those on which observations were made on the extensive tidal flats at Agfayan Bay and vicinity. These flats, at low tide, present excellent feeding grounds for waders and in 1945 were undisturbed by parties of service personnel, because the area was "off-limits."

[Table 8] shows that Pluvialis dominica, Numenius phaeopus, and Heteroscelus spp. were the shore birds most frequently found at Guam in this period. Pluvialis dominica was the most numerous of the three species. Of Heteroscelus there was approximately equal representation of H. incanus and H. brevipes as indicated by specimens collected. These birds were not identified to species in the field.

Although records were made only infrequently in the spring migration, such information as was obtained indicates that the populations were largest in March and early April. On April 24, Pluvialis dominica was the only bird observed on beaches and in upland openings. On April 26, a single Limosa lapponica was recorded. On May 15, no shore bird was seen on a trip along several beaches. In late May and early June, single individuals of Heteroscelus were found. Of this genus, those collected in May were in nuptial plumage, and those collected in June were in winter plumage and probably should be classed as non-migrants. Numenius phaeopus was occasionally recorded beginning in early June, but waders were totally absent from beaches at Agfayan Bay and vicinity on June 18 and 19. Few shore birds were seen in early August. In late September, birds, especially Pluvialis dominica, Numenius phaeopus, and Heteroscelus spp., were numerous. These species were numerous until October 24, when observations were discontinued.

Of the 17 species of migratory shore birds recorded from the Mariana Islands, eight were identified. Of these eight, three species, Limosa lapponica, Actitis hypoleucos, and Charadrius mongolus, were found on only one occasion. Never more than four species were identified on a single field trip. These data give an idea of the lack of variety of species that may be observed on Micronesian islands.

Table 9. Populations of Migratory Shore Birds Seen at Ulithi Atoll in 1945

Table 9. Populations of Migratory Shore Birds Seen at Ulithi Atoll in 1945

^* Figures based on identified skins.

x Observed but numbers not recorded.

^* Figures based on identified skins.

x Observed but numbers not recorded.

[Table 9] lists the shore birds seen at Ulithi Atoll, Caroline Islands, on eight field excursions in the period from August 14 to August 22, 1945. Of seven species of shore birds known to visit the atoll, six were taken in this period. As observed at Guam, Pluvialis dominica and Numenius phaeopus were the species most frequently found. Heteroscelus was seen on three occasions; those collected were identified as H. incanus. Most of the shore birds were seen at Pau and Losiep, islands unoccupied by man. Similar tidal flats are present at most of the other small islands in the atoll, but these islands (Asor, Fallalop, Potangeras, Fassarai and Mangejang were visited) were occupied by small detachments of service personnel or by natives, which may have tended to keep many of the shore birds away. At the more populated islands of Asor and Fallalop, no shore birds were seen. Almost as many species were recorded at Ulithi on the eight field trips as were found by the author at Guam in eight months of observations.

Table 10. Populations of Migratory Shore Birds Seen at the Palau Islands in 194

Table 10. Populations of Migratory Shore Birds Seen at the Palau Islands in 194

^* Observations made on beaches at Akarakoro Point, Peleliu.

x Observed but numbers not recorded.

^[+] Observations made at fresh water ponds.

^[++] Figures based on identified skins.

^* Observations made on beaches at Akarakoro Point, Peleliu.

x Observed but numbers not recorded.

^[+] Observations made at fresh water ponds.

^[++] Figures based on identified skins.

[Table 10] presents field counts at the Palau Islands in the period from August 24 to September 21, 1945. Of 20 species of shore birds known from the Palaus, 17 species were collected or identified on this trip. It was apparent that the fall migration was at its height at this time. Birds were numerous at inland openings and ponds, air field strips, and on the extensive tidal flats at Akarakoro Point. The latter area is between Peleliu and the adjacent island of Ngesebus to the north. Several observations were made at this area (as indicated by the dates marked with asterisks in the table); on September 8, 271+ shore birds were counted; on September 16, 129+ were counted. Six species were observed to be abundant. The majority of the birds found at these beaches were in small flocks which consisted of several birds of one or more species.

The birds observed at Angaur on September 21 were seen at several fresh and brackish ponds. Four species (Tringa glareola, Erolia acuminata, Limicola falcinellus, Gallinago megala), which were not taken on the tidal flats or elsewhere at Peleliu, were found at these ponds.

The abundance, and more especially the variety, of shore birds at the Palau Islands during this period was in marked contrast to the smaller and less diversified populations of shore birds in rather similar insular environments at Ulithi and Guam. These differences offer support for the supposition that the Asiatic-Palauan Migratory Shore Bird Flyway is distinct from the Japanese-Marianan Migratory Shore Bird Flyway.

Land and Fresh-water Birds

The land and fresh-water avifauna of Micronesia consists of 147 kinds of birds. Of these, 37 kinds are non-residents, 104 kinds are residents, and 6 kinds have been introduced by man. The 104 resident birds include 98 kinds (94 percent) which are found only within the confines of Micronesia. Included in these 98 kinds which are restricted to Micronesia are 5 endemic genera, 31 endemic species and 76 endemic subspecies.

Gulick (1932: 407, 413) stresses that the fauna and flora of the oceanic islands may be "disharmonic" (he uses Easter Island as his example) and says, "It is evident that mature groups of islands will attain an internal harmony, from the standpoint of the systematist. But this harmony, instead of reflecting the pre-existing harmony of some continental source (as in the case of the continental islands or land-bridge remnants) will be recognizably derivable by descent from a quite limited number of original importations, at the start distinctly miscellaneous and 'disharmonic'." Analysis of the land and fresh-water avifauna of Micronesia supports Gulick's view.

Fig. 7. Divisions of the islands of part of the Pacific Basin from the standpoint of the distribution of land birds and fresh-water birds: (1) Micronesia; (2) Hawaii; (3) Central Polynesia; (4) Eastern Polynesia; (5) Southern Melanesia; (6) Melanesia.

As mentioned previously, the islands of Micronesia, from the zoogeographical viewpoint, have been regarded as a part of the Polynesian Subregion of the Australian Region. Mayr (1941a: 192) defines the Polynesian Subregion as comprising "all the tropical and subtropical islands of the Pacific Basin which indicate by their impoverished fauna that they have had no recent continental connection (after early Tertiary) and which derived the major part of their fauna directly or indirectly from the Papuan Region or jointly from Australia and the Papuan Region." As based on the distribution of the resident avifauna, Mayr (1941a:193) subdivides the Polynesian Subregion into the following districts: Micronesia ("including Palau, the Marianne, Caroline, Marshall, and Gilbert islands"); Central Polynesia ("including Fiji, Tonga, Samoa, Phoenix, Ellice, Union islands, and a number of small islands, such as Rotuma, Fotuna, Keppel, Niue, Niouafu, and Uvea"); Eastern Polynesia ("all the islands east of 165° W"); and Southern Melanesia ("including the Santa Cruz group, Banks Islands, New Hebrides, Loyalty Islands, and New Caledonia"). He considers that the Hawaiian Islands, Solomon Islands, and possibly New Caledonia are bordering districts to the Polynesian Subregion. [Figure 7] shows the divisions of the islands of the Pacific Basin from the standpoint of the distribution of the land and fresh-water birds. I have placed the Gilbert and Marshall islands in the Central Polynesian rather than in the Micronesian District. For purposes of discussion in this report, however, I am considering the Marshalls to be a part of Micronesia. The birdlife of the Bonin and Volcano islands northward of the Marianas is regarded as having its closest affinities to the Japanese avifauna. The Papuan or Melanesian Subregion of the Australian Region includes the districts of New Guinea and Northern Melanesia, including the Bismarck Archipelago, the Admiralty Islands, and the Solomon Islands.

The resident land and fresh-water birds of Micronesia have been derived from several sources. Studies of these birds and their closest relatives in adjacent areas indicate that the avifauna has been derived from five different sources: Polynesia, Melanesia, the Moluccas and Celebes, Philippines, and Palearctica.

Polynesian Component

Aphanolimnas monasa (extinct?), Ptilinopus porphyraceus, and Ducula oceanica are the only species of birds which have reached Micronesia directly from Polynesia. There are in Micronesia, as Mayr (1941b: 204) points out, eight species "which are members of typically Polynesian species or genera" and six species which are either Papuan or Polynesian. The relationships between Polynesian and Micronesian birds is evident, but insofar as the pathways of colonization are concerned the majority of these Micronesian species listed by Mayr have come from elsewhere than Polynesia and the birds of these two areas are thought to have arisen from common ancestors. Aphanolimnas, Ptilinopus, and Ducula apparently invaded Micronesia from Central Polynesia via the Marshall Islands through a rather continuous chain of islands and atolls. Aphanolimnas is known only from Kusaie in the extreme eastern part of the Carolines while Ptilinopus and Ducula are known from the Marshalls, Carolines, and Palaus.

Melanesian Component

The Papuan or Melanesian Region (New Guinea, Bismarck Archipelago, Solomon Islands) has supplied to Micronesia its greatest number of endemic land and fresh-water residents. Fifty kinds of birds belonging to the following species reached Micronesia from Melanesia: Nycticorax caledonicus, Megapodius lapérouse, Ptilinopus roseicapillus, Gallicolumba xanthonura, G. canifrons, Caloenas nicobarica, Halcyon cinnamomina, Trichoglossus rubiginosus, Collocalia inquieta, Edolisoma tenuirostre, Rhipidura rufifrons, Metabolus regensis, Monarcha godeffroyi, M. takatsukasae, Colluricincla tenebrosa, Aplonis opacus, A. pelzelni, A. corvinus (extinct?), Cleptornis marchei, Myzomela cardinalis (probably by way of Southern Melanesia), Rukia palauensis, R. oleaginea, R. ruki, R. sanfordi, Erythrura trichroa. The colonization of Micronesia by these species has probably extended over a considerable period of time. Megapodius, Trichoglossus, and Aplonis corvinus may represent older colonizations which have become well differentiated from the ancestral forms; Nycticorax, Myzomela, and Erythrura may have become established later and have had "less time" to become modified from the ancestral forms. Birds from Melanesia have reached Micronesia probably by direct flight to the Caroline Islands. Aided by favorable winds which blow from the southwest, south and southeast during the period from May to November, birds, particularly the young of the year, might conceivably be blown in the direction of the Carolines, where 57 percent of the birds derived from Melanesia reside. The Palaus are populated with 15 percent, the Marianas with 28 percent, and the Marshalls (lacking "high" islands) with none; these may be secondary colonizations from the Carolinas excepting Ptilinopus, Megapodius, Gallicolumba canifrons, Cleptornis, and Colluricincla. The Marshall Islands have received no avian components from Melanesia. The absence of "high" islands in the Marshalls and the possible inability of birds accustomed to life on the luxuriant islands of Melanesia to become established on relatively barren atolls are logical reasons for this. Instead of New Guinea itself, the outlying islands of Melanesia (Bismarck Archipelago, Solomons, Southern Melanesia) probably have been the principal "taking-off" places for birds invading Micronesia.

Moluccan and Celebesian Components

Birds which reached Micronesia by way of the islands of Celebes and the Moluccas may have been derived originally from Melanesia. The following birds appear to have used this route: Porphyrio porphyrio, probably Halcyon chloris, Rhipidura lepida, Myiagra oceanica, Zosterops conspicillata, and Z. cinerea. These birds apparently became established initially in the Palaus; Porphyrio and Rhipidura lepida have not been recorded elsewhere in Micronesia, but Myiagra and the two species of Zosterops have spread to the Carolines and Marianas, although not into the Marshall Islands. Wind from the southeast in summer and fall has probably been a factor aiding these colonizations. The population of Gallinula chloropus resident at Palau may also have arrived by this route.

Philippine Component

Ten of the kinds of birds of Micronesia have come from or by way of the Philippine area. These are known principally from the Palaus and the Marianas and include: Rallus philippinus, R. owstoni, Poliolimnas cinereus, Caprimulgus indicus, Corvus kubaryi, Psamathia annae, Artamus leucorhynchus, possibly Lonchura nigerrima, and Collocalia inexpectata. The Philippines may have been the actual point of dispersal of the birds (example, Psamathia), or may have been used as a stepping stone to Micronesia by birds coming from Melanesia (examples, Rallus and Artamus), by birds from Malaysia (example, Collocalia), and by birds from Asia (example, Caprimulgus). Two birds of this component have reached the islands of eastern Micronesia. A subspecies of Lonchura nigerrima is endemic at Ponapé, and a subspecies of Poliolimnas cinereus occurs on several islands in the Carolines and has even been recorded at Bikini in the Marshall Islands. Three species are known only from the Palaus; two are known only from the Marianas.

Palearctic Component

Fig. 8. Faunal areas from which the resident land birds and fresh-water birds of Micronesia have been derived. (1) Palearctica; (2) Philippines; (3) Moluccas and Celebes (Malaysia); (4) Melanesia (New Guinea and northern Melanesia); (5) Polynesia.

Birds of Micronesia which have been derived directly from Palearctica are Gallinula chloropus guami, Otus podarginus, Asio flammeus, Acrocephalus luscinia and Anas oustaleti. Apparently Gallinula, Asio, and Acrocephalus arrived in Micronesia by way of the chain of islands from Japan southward to the Bonins, Volcanoes, and Marianas. Otus reached Palau from Asia, possibly by way of the Philippines. The smallness of the representation of this component may result partly from lesser ability of the northern birds to adapt themselves to, and to establish themselves on, the semi-tropical and tropical islands of Micronesia as compared with birds from Melanesia where the climate and ecologic conditions resemble more closely those found in Micronesia. Evidence supporting this possibility is the large number of Palearctic residents in the Bonin and Volcano islands as compared with fewer in the Marianas; the Bonins and Volcanoes are less tropical and more temperate in climate.

Table 11 lists the birds concerned, by faunal areas from which the birds have been derived and shows the number of kinds of birds which are present as a result of these colonizations. There is some overlap in the numbers since some endemics may be found in more than one area in Micronesia. [Figure 8] shows the faunal areas from which the endemic land and fresh-water birds of Micronesia have been derived. Melanesia (Papua) supplied 52 percent of this population. Birds reaching Micronesia by way of the Moluccas and Celebes include 21 percent of the total population. The Philippines have supplied 10 percent; Polynesia, 9 percent; and Palearctica, 8 percent. This population of endemic land birds and fresh-water birds has seemingly evolved from 46 colonizations, of which 27 have been derived from Melanesia, 6 from the Philippines, 5 from the Moluccan and Celebean areas, 5 from Palearctica, and 3 from Polynesia.

The Palaus have received a large part of their avifauna from the west (Moluccas, Philippines, Palearctica). Their Melanesian component is mostly the result of secondary colonization from the Carolines. The Carolines have received a greater share of their land birds and fresh-water birds from Melanesia and a smaller share from Polynesia. The Marshalls are definitely associated with the Polynesian element. The Marianas exhibit a considerable amount of secondary colonization from other Micronesian islands, as well as some unique components from the Philippines, Melanesia, and Palearctica. Thus, the number of endemics in Micronesia provides little information concerning the actual number of successful colonizations by birds from other areas. Many of the endemics probably have resulted in this way: Individuals of an endemic subspecies flew to another island and there underwent further differentiation, producing another endemic subspecies. Such secondary colonization probably is going on now.

This analysis of the avifauna shows that Micronesia, with the exception of the Marshall Islands (and the Gilbert Islands), has but little affinity to Polynesia. It has greater affinity, from the zoogeographical standpoint, with the Papuan Region (Melanesia).

Table 11. Avifaunal Components Which Make Up the Endemic Resident Land and Fresh-water Bird Population of Micronesia

Table 11. Avifaunal Components Which Make Up the Endemic Resident Land and Fresh-water Bird Population of Micronesia

Speciation

Of the 104 native fresh-water birds and land birds which are resident in Micronesia, only 7 kinds or 6.5 percent remain undifferentiated from populations elsewhere. These birds are Phalacrocorax melanoleucus, Pandion haliaetus, Demigretta sacra, Ixobrychus sinensis, Anas poecilorhyncha, and possibly Lonchura punctulata (may be an introduction by man). Another bird, Gallinula chloropus, a resident at Palau, may or may not be distinct from the gallinule of Malaysia, G. c. orientalis. Of the 104 resident birds, 97 kinds or 93.5 percent have become differentiated and can be separated taxonomically from populations elsewhere. Of the kinds of birds which are found only in Micronesia, there are 5 endemic genera (16 percent), 31 endemic species (32 percent) and 76 endemic subspecies (75 percent). If we consider the avifauna of Micronesia as a single element, the endemism is high as compared with that on larger and less isolated islands. For example, Mayr (1944a:174) found 137 resident birds on Timor including 22 endemic species (16 percent) and 67 endemic subspecies (47.5 percent). Stresemann (1939b:313) found 220 species including 84 endemic species (38.2 percent) on Celebes. Mayr (1944a:174) also writes that on Java, of 337 breeding species, 16 (4.8 percent) are endemic, and on New Caledonia, of 68 species 19 (27.9 percent) are endemic. Speciation in Micronesia has not progressed much farther than that at New Caledonia and not so far as at Celebes, but subspeciation has progressed considerably more than at the island of Timor. The avifauna of the Hawaiian Islands, as recorded by Bryan and Greenway (1944), has 73 resident land birds and fresh-water birds, all of which are endemic, including one family, 23 genera and 36 species. The North American night heron, Nycticorax n. hoactli, may be included in this list as the only resident which is undifferentiated. The development of full specific differentiation within the resident avifauna is greater in the more isolated Hawaiian chain where 49 percent of these birds are regarded as endemic species, while in Micronesia, which is less remote from other bodies of land, the specific endemism is only 32 percent.

Table 12. Endemism in Families of Native Land and Fresh-water Birds in Micronesia

Table 12. Endemism in Families of Native Land and Fresh-water Birds in Micronesia

^* Aphanolimonasa is included but may be extinct.

^[+] Aplonis corvinus is included but may be extinct.

^* Aphanolimonasa is included but may be extinct.

^[+] Aplonis corvinus is included but may be extinct.

[Table 12] lists the families of land birds and fresh-water birds which have resident members as part of the avifauna of Micronesia. It can be observed from the table that only two families are represented by no endemic kinds, several families are represented by one or two endemic kinds, and others are represented by as many as 14 endemic kinds. Endemism has reached its greatest development in the families Rallidae (6), Columbidae (13), Apodidae (5), Alcedinidae (7), Sylviidae (5), Muscicapidae (14), Sturnidae (9), Meliphagidae (7), and Zosteropidae (14). Generic endemism is greatest in the Sylviidae where one endemic genus occurs among 5 endemic species and subspecies (20 percent), in Rallidae one in 6 (17 percent), in Meliphagidae one in 7 (14 percent). Specific endemism is greatest in Psittacidae and Corvidae where the single representative of each family in Micronesia is considered specifically distinct (100 percent), in Megapodidae and Strigidae one in 2 (50 percent), in Muscicapidae and Zosteropidae 6 in 14 (43 percent) in Sylviidae 2 in 5 (40 percent), in Rallidae 2 in 6 (33 percent), in Sturnidae 3 in 9 (33 percent) in Columbidae 4 in 13 (31 percent). Subspeciation within species which are endemic in Micronesia has occurred in 8 families, occurring within two species in each of the families Columbidae and Zosteropidae and once in each of the families Megapodidae, Apodidae, Alcedinidae, Sylviidae, Muscicapidae, and Sturnidae.

In summary, the families of land and fresh-water birds found in Micronesia which have the greatest number of endemic forms are Muscicapidae (14), Zosteropidae (14), Columbidae (13), and Sturnidae (9). Speciation has occurred in the single representative of the families Psittacidae (Trichoglossus rubiginosus) and Corvidae (Corvus kubaryi). Where family representation is large, speciation has occurred most frequently, as in the Muscicapidae (6 in 14 = 43 percent), in the Zosteropidae (6 in 14 = 43 percent), and in the Columbidae (4 in 13 = 31 percent). Subspeciation has occurred in 8 families, in two species in the Columbidae and Zosteropidae and in one species in each of 6 other families.

Time of Colonization

Previously (and in the accounts of the species to follow), comments are made concerning the subjects of from where and by what route the various kinds of birds have arrived at Micronesia. The problem of when these birds arrived is a difficult and usually unanswerable one. Although geology provides some evidence on the relative age of the islands, and although deposits of bird guano on now elevated coral islands show that oceanic birds have inhabited these islands for a long time, there is no evidence to show the time of the first colonization by land birds. No fossil remains of land birds or fresh-water birds have been found in Micronesia. The relative extent of differentiation in color and structure, which has taken place between different birds, offers one means for estimating the relative length of residence in the area, provided all other factors are equivalent. Concerning the birds of the Galapagos, Lack (1947:113) writes "That Darwin's finches are so highly differentiated suggests that they colonized the Galapagos considerably ahead of the other land birds." Evidence from this source actually is of little value, because the speed of evolution is unknown and its rate may be different in different species, even though they live under the same circumstances. Dobzhansky (1941) says that evolution is a modification of the genetic equilibrium, which, if true, may not result in similar manifestations in different kinds of birds living under the same conditions of life. Relative antiquity of the birds might be ascertained by measuring their ecologic adaptations. The Guam Rail (Rallus owstoni) and the Micronesian White-browed Rail (Poliolimnas) can be examined in this way. R. owstoni has the ability to live in both brackish and fresh water swamps, as well as in the scrub and grass of the uplands and in the virtually barren, rocky areas in the dense jungles. Poliolimnas, on the other hand, appears to be restricted to swampy areas in Micronesia. If the swampy areas were removed this rail probably would become extinct. R. owstoni appears to have been resident in Micronesia longer than Poliolimnas. However, ability to live in a variety of habitats might be acquired by R. owstoni in a relatively short time.

Another possibility is that the birds, which are less differentiated from their ancestral stocks, may be less differentiated because of suppression of newly evolved characters by dilutions, which result from interbreeding with new birds, which may be arriving at irregular intervals from the ancestral home. Interbreeding of the resident population with newcomers may overshadow any modifications which might have appeared as a result of insular isolation, especially modifications which have little adaptive significance. One would suspect, from their modifications, that Rallus owstoni, Metabolus rugensis, Corvus kubaryi, and other endemic forms have experienced less of this "dilution," than such birds as Rallus philippensis pelewensis, Artamus leucorhynchus pelewensis, Myzomela cardinalis, and others. Murphy (1938) mentions this "dilution" effect in his discussion of "strong" and "weak" subspecies among warblers of the Marquesas. He writes that "strong" subspecies may develop if the birds are present on islands which are upwind from islands containing related subspecies. The wind acts to block interisland migration in these weak-flyers. On the other hand, "weak" subspecies may show the effect of "dilution," being situated on islands downwind from islands containing related subspecies. The direction of the wind acts to aid the weak flyers to move to the downwind islands and continually "dilute" the resident subspecies. Similar examples can be cited for Micronesian birds. Hesse, Allee, and Schmidt (1937:87) write, "Endemism on islands is most frequent in forms for which the difficulty of reaching the island is most extreme, so that new increments of the parent form are unlikely to follow."

Employing the criteria mentioned above, the birds of Micronesia can be tentatively divided into four groups as regards the relative time when they arrived at the islands:

1. Birds of ancient colonizations which reached certain individual islands, became modified, and dispersed no farther. Examples are Aphanolimnas, Rallus owstoni, Aplonis corvinus, Metabolus rugensis, and Corvus kubaryi.

2. Birds of ancient colonizations which reached or dispersed through a number of islands but are now restricted to relatively few islands. Examples are Ducula oceanica, Ptilinopus porphyraceus, Megapodius lapérouse, Asio flammeus, and Acrocephalus luscinia.

3. Birds of ancient, or possibly more recent, colonizations which initially reached or subsequently dispersed to many of the islands of Micronesia possessing habitat suitable for them. Examples are Myzomela cardinalis, the two species of Halcyon, Aplonis opacus, and Zosterops conspicillata.

4. Birds of rather recent colonizations, which may have reached only a few islands and are relatively unmodified from their parental stocks. Examples are Artamus leucorhynchus, Caprimulgus indicus, Poliolimnas cinereus, and Nycticorax caledonicus.

Factors Causing Dispersal

Darlington (1938:274) in discussing the origin of the fauna of the Greater Antilles uses the term "over-water dispersal" in referring to the spread of terrestrial animals across water. He is against the use of the term "accidental dispersal" since many factors besides accident are involved. He contends, as do others, that certain forms of organisms, owing to their "nature and behavior" cross water barriers more successfully than others. These observations may be applied to the "over-water dispersal" of birdlife to the islands of Micronesia. Certain groups of birds are more evident in Micronesia than others. Certain groups of birds which are found on other islands of the Pacific basin are found in Micronesia only in small numbers or may not be represented; Mayr (1945a:284) writes, "Remarkable is the almost complete absence of parrots and honey-eaters, the small number of pigeons and the absence of such widespread genera as Lalage, Turdus, and Pachycephala." The absence of some species and the presence of others produces the characteristic insular effect termed "disharmonic" by Gulick (1932:407), as compared with the continental area or island which derived its avifauna by way of a land bridge. One would think from looking at [table 12] that members of the families Rallidae, Columbidae, Muscicapidae, Sturnidae, and Zosteropidae were the most successful colonizers in Micronesia on the basis of the number of successful colonizations (not necessarily on the number of endemics developed from a single colonization). Of these families, Sturnidae and Zosteropidae and possibly Columbidae contain species which often move in flocks. Furthermore, these families as well as the Muscicapidae feed on either fruits, seeds, or insects, any one of which is a type of food which might "give out" suddenly, stimulating a migratory behavior within the birds. From a flock embarking seaward in "search" of more food, a part or even all of the birds might survive in a chance flight to an isolated island in Micronesia. If a flock containing both males and females reaches an island, the species has a good chance of becoming established. Evidence that such a rapid colonization by flocks of birds can take place is found in the remarkable colonization of New Zealand by Zosterops lateralis from the Australian area. The bird was first seen as a winter migrant in New Zealand in 1856 and records of nestings were obtained at North Island in 1862, according to Oliver (1930:489). In the case of rails there is no evidence that they move in flocks; however, they are among the most successful colonizers and are on many of the oceanic islands in the tropical and subtropical oceans. Representatives of several species of the family Rallidae have invaded Micronesia and have successfully established 6, or possibly 7, "colonies."

Darlington (1938:274) further writes that "it is no accident that some islands, because of their nature and position, the direction of winds and currents, and the nature of the neighboring land, receive more organisms than other islands do." Semper (1881:294) writes that the distribution of flying creatures "must be in a great degree dependent on the direction and strength of atmospheric currents." These statements are applicable to the history of the avifauna of Micronesia. The Caroline Islands, for example, present a "broad front" for wanderers from the Melanesian islands. As mentioned previously, the prevailing winds in the late spring, summer, and early fall are from the south, southwest, and southeast and would favor bird flight to the northward towards the Carolines. In addition, the breeding season of many of the birds in Melanesia is from November to February, and in the spring and summer, restless young birds seeking living space might fly seaward and aided by the winds fly northward towards Micronesia. Adults, which may have well-established home territories, may be less likely to attempt such a movement.

One could conclude from the above discussion that the Micronesian islands, especially the Carolines, might be well populated with a large variety of birds from Melanesia, a scant 500 or more miles away. As it turns out, there are only a few islands in this extensive archipelago possessing proper vegetation, fresh water, and other qualities which make them capable of supporting the land and fresh-water birds of Melanesia. The few islands which have these qualities are the so-called "high" islands, including the entire Mariana chain, the Palaus, and four widely separated islands in the Carolines: Yap, Truk, Ponapé, and Kusaie. The other islands of Micronesia are "low" coral islands, which often lack fresh water and have a meager variety of fruits, insects and other foods. Thus, if birds do reach Micronesia but arrive at the atolls instead of the "high" islands, these birds may be doomed. It is noteworthy that the Micronesian islands are small compared with the Solomons, Fijis, and others. The smaller the island, the fewer the number of ecologic niches and the fewer the kinds of birds present.

Mayr (1941b:215) writes that the distance from the nearest land mass and the climatic conditions are important factors controlling dispersal. With regard to the degree of remoteness of the islands, [table 13] lists the number of resident land and fresh-water birds present in the Palaus and the "high" islands of the Carolines. Also, the approximate distance from the nearest large land mass and the area in square miles are given. There is some correlation between the distance from the nearest land mass and the number of resident land birds and fresh-water birds. For example, Palau, with 32 resident birds, is only 410 miles from the nearest land mass whereas Kusaie, with only 11 resident birds, is 720 miles from the nearest land mass. The comparative size of the land mass must also be taken into account, as shown by the fact that the large island of Ponapé contains more kinds of birds but is more remote from large land masses than either Yap or Truk.

Table 13. Correlation Between Number of Resident Land and Fresh-water Birds and Distance From Large Land Masses of "High" Islands of Micronesia

Table 13. Correlation Between Number of Resident Land and Fresh-water Birds and Distance From Large Land Masses of "High" Islands of Micronesia

Climatic factors are important in the dispersal of bird life; Micronesia, where the climate is tropical to subtropical, is better suited for colonization by birds from the tropics (Melanesia) than by birds from the temperate or cold climates (Palearctica). The climatic factor may be one of the principal reasons why birds from Palearctica make up only a small part of the avifauna of Micronesia.

Analysis of Speciation

The process of speciation within insular populations has been discussed by many authors. Hesse, Allee, and Schmidt (1937:517) list the motives for differentiation as, "Special character of insular faunae rests on the conditions common to all islands—isolation, freedom from competition, space restriction, and special insular climates." This combination of characteristics is seldom found elsewhere in nature, and as Murphy (1938:357) points out, an island is the nearest approach to a "man-controlled laboratory." Isolation of small populations is probably the most influential factor in the process of speciation in insular organisms. Lack (1947:134) writes that "in all organisms the isolation of populations is an essential preliminary to the origin of new species." Buxton (1938:265) also stresses this point with regard to the formation of species of insects in Samoa and emphasizes that evolution may occur more quickly in small populations. When mutations appear in such small and isolated populations, they have a greater chance to become fixed than do mutations in less restricted populations in a larger land mass, where such a mutation might be lost by the swamping effects of outbreedings. In addition, Wright (1931 and elsewhere) suggests the possibility of change by accidental elimination and recombination of hereditary characters in micropopulations. This mechanism could well be a factor in Micronesian bird populations, many of which possess no more than a few hundred individuals. Huxley (1938:256) emphasizes that "accidental" mutations may be perpetuated in small, isolated groups. It might be added that such changes might be either advantageous or disadvantageous to the organism concerned. Huxley (1938:263) states also that geographic isolation may promote nonadaptive differentiation, which may be caused by "colonization by a random sample" or by subsequent "preservation of nonadaptive mutations in numerically small isolated groups." Mayr (1942b:237) cites the importance of the "founder" principal for reduced variability in small populations. He points out that if the "founders" of the population carried with them only "a very small proportion of the variability of the parent population," one would expect to see divergence from the ancestral stock.

Freedom from competition, especially interspecific strife, is an important factor in differentiation; this is especially true in the early period of colonization. Lack (1947:113) points to the absence of food competitors, especially in the initial period of colonization, as an important influence in the evolution of Darwin's finches at the Galapagos Islands. Once a population has become established and "adjusted" to a given environment on a small island, intraspecific competition might bring about adaptative selection. Subsequent colonists might be eliminated by the competition brought about by these previously adapted organisms, especially if both organisms were adapted for life in the same ecologic niche. Space restriction may be important in such Micronesian birds as Rhipidura and Myiagra, which appear to possess recognizable territories. A new colonist entering the territory of one of these birds might be forced out. This competition might not play such an important part among birds, which live in flocks and do not range in closely guarded territories; birds in this group include some pigeons, starlings, and white-eyes.

Freedom from the pressure of predation probably exerts a direct influence on formation of species. Aside from a few migrant hawks and two kinds of resident owls, most of the avifauna feeds on vegetable and invertebrate foods. The large lizard Varanus may be classed as the only native predator on many of the islands. Man has been responsible for the introduction of rats, house cats, and other mammals, which may be destructive to birds. Thus, before the advent of man the factor of predation may not have been of great consequence. As mentioned previously, nonadaptive modifications may be perpetuated where the "weeding-out" process by predation is not an influence. Flightless rails have apparently developed in the absence of predation.

The absence of the pressure of predation should remove a certain amount of control on the population turn-over. As Hesse, Allee, and Schmidt (1937:521) write, a characteristic of the faunas of oceanic islands is the fact that they are distinguished by the occurrence of "disproportionately developed taxonomic groups in which one or a few basic types have undergone adaptative radiation and come to fill unduly large proportions of the population as compared with conditions that obtain on neighboring continents." Lack (1947:114) writes, "that the absence of predators may well have accelerated the adaptative radiation" in the Galapagos finches. In Micronesia, the starling (Aplonis opacus) dominates much of the available habitat on some of the Caroline atolls, and even on "high" islands, where other land birds are present. There appears to be no tendency towards selective adaptations occurring, or towards ecologic isolation.

Available data indicate that the life spans of individual birds in Micronesia may be short. For example, it was obvious on many of the islands visited by the NAMRU2 party that starlings (Aplonis opacus) in immature plumage outnumbered starlings in adult plumage, although it is possible that immature plumages are retained longer in these island birds than in others. Similar observations were made by Coultas, who noted the ratio of birds in immature plumage to birds in adult plumage at Kusaie to be 5 to 1. If the life span is shorter in these insular forms as compared with that of the ancestral stocks, the higher annual population turn-over would allow for the speed of genetic changes to be accelerated.

The origin of species by hybridization between different kinds of organisms has been a subject of frequent discussion. Lack (1947:100) concludes that it is improbable that hybridization has played an important part in the origin of new kinds of birds. Nevertheless, the absence of sufficient mates in the confines of a small island probably stimulates the crossbreeding between two species of birds. Fertile offspring of such a cross might conceivably account for some of the populations, the origins of which are puzzles to present day taxonomists. Such Micronesian forms as Metabolus and Cleptornis could conceivably have been derived in such a manner. Yamashina (1948) has described the origin of Anas oustaleti as a result of hybridization between A. platyrhynchos and A. poecilorhyncha. It might be difficult to explain every case of the formation of other insular species on the basis of the effects of isolation and paucity alone. However, Mayr (1942b:236) includes the development of questionable and unusual kinds of insular forms in a general statement: "The potentiality for rapid divergent evolution in small populations explains also why we have on islands so many dwarf or giant races, or races with peculiar color characters (albinism, melanism), or with peculiar structure (long bills in birds), or other peculiar characters (loss of male plumage in birds)."

Nutrition may be also a factor influencing speciation in bird life. The types of food plants (coconut, papaya, breadfruit, pandanus, etc.) might be similar on a Micronesian island and on a continental island in the Philippine region; however, the value of these plants as foods might vary and might reflect differences in mineral content of the soils. For example, if the soils on an island lack, or by leaching out have lost, sufficient amounts of potassium and other elements, plants may store foods, not as proteins, but possibly as carbohydrates, simple sugars, or alkaloids. Whether nutritional influences might have a selective effect on the bird populations, has not been ascertained.

In summary, it may be said that genetic change altering the phenotypic expression of avian characteristics is no more apt to happen in insular populations than in continental populations but genetic change may have a greater chance of being perpetuated in small insular populations where isolation, limited competition, freedom from the selective influences of predation, and other factors exert influences.

[CONSERVATION OF THE AVIFAUNA OF MICRONESIA]

The islands of Micronesia are small and their occupation by man often produces serious effects on the endemic animal life of the islands. The vulnerability of insular bird populations is well attested by the fact that the majority of birds, which have become extinct in the past two hundred years, have been insular forms. Two birds in Micronesia, the Kusaie Rail (Aphanolimnas) and the Kusaie Mountain Starling (Aplonis corvinus), are known to be either extinct or so rare that they have not been taken since the time of Kittlitz, who visited the island of Kusaie in December, 1827, and January, 1828. Other birds (Anas oustaleti, Caloenas nicobarica, Megapodius l. lapérouse, and Metabolus rugensis) have become reduced in numbers and may be threatened with extermination.

Nelson (1921:270-274) has described the following agencies destructive to island life of the Pacific: fire, volcanic eruptions, tidal waves, hurricanes, clearing of the land, introduction of domestic animals and grazing, introduction of wild animals and birds. Mayr (1945c) also presents a discussion of conservation problems in these islands.

Fire is a serious hazard to island life, especially to the land birds. It destroys both food and cover, these two habitat requirements being most essential to the birds. The firing of open lands to improve grazing conditions was a practice which persisted in the Marianas during the time of the Spanish. This practice has declined, but the resultant vegetational changes and erosion have adversely affected the avifauna. Tidal waves and hurricanes (typhoons) are occasionally of such intensity as to flood low coral atolls. Such events are damaging to, or might even exterminate populations of land birds (Aplonis, Acrocephalus and others), and prevent colonizations which might otherwise occur. Clearing of the land for agricultural use probably has affected the avifauna, especially on the island of Tinian where much of the island has been placed in cultivation. The occurrence of domestic stock, especially feral hogs and cats, has affected the birds. Hogs, apparently, have been in the islands for a long time. The English privateer, Lord Anson, visited Tinian in October, 1742, and noted a large number of hogs present at that time. At Guam, in 1945, the NAMRU2 party found both hogs and cats moving freely in all parts of the island. Stomachs of cats examined showed that they had been feeding principally on rodents.

Introduction of wild animals and plants have not been so extensive as in the Hawaiians or other islands. There have been at least five importations of land birds to Micronesia as well as several mammals, other vertebrates and invertebrates. The effect of these established colonies on the native bird life has not been studied.

The late world war has brought changes to the population of bird life in Micronesia. The author (1946b) has elsewhere described some of the effects of the bombing, invasion, and occupation of small islands. Some islands, like Peleliu, suffered severely from bombing and invasion operations. Some islands, especially smaller ones like Kwajalein and Ulithi, were partly or almostly entirely cleared of vegetation by occupation forces. Other effects were caused by "recreational" shooting of birds by garrison forces; introductions of pests in materials unloaded; and pest control by clearing, draining, and spraying with DDT and other insecticides to the detriment of inoffensive species.

It is obvious that a well-planned program of conservation should be placed in operation to insure survival of the endemic avifauna of Micronesia.

[THE FUTURE OF ORNITHOLOGICAL RESEARCH IN MICRONESIA]

Collections of birds have been made at most of the major islands of Micronesia, and it is thought that there are but few if any unnamed birds in the region. The distribution of several species has not been completely investigated, especially those land birds (Ducula, Ptilinopus, and Aplonis) which inhabit coral atolls in the Carolines and Marshalls. The bird life of the northern Marianas is also incompletely known. Continued observations in the Micronesian islands will increase our knowledge of the kinds of migratory shore birds and migratory land birds which reach the island as winter visitors. Further information is needed concerning the breeding activities of sea birds in Micronesia, especially in the Marshalls and Carolines.

The systematic status of most of the birds in Micronesia is already established. It is hoped that the present account advances our knowledge of the methods of colonization. Although these fundamental investigations have been nearly completed in Micronesia the field of avian ecology has been relatively untouched. In the past, expeditions have visited Micronesia with the aim of obtaining within a short time collections of the animal life as large and as representative as possible. Many of the collectors made few or no field notes on the bird life; some, like Finsch, Kubary, Marche, and Coultas, made valuable observations on the habits of the birds. Intensive ecological researches may be accomplished more thoroughly by resident investigators, who can devote full time to such pursuits.

[METHODS AND ACKNOWLEDGMENTS]

My own opportunity to study the bird life of Micronesia came as a member of the scientific staff of the Laboratory of Mammalogy of United States Naval Medical Research Unit No. 2 (NAMRU2) in the late war. The primary duty of this laboratory was to obtain examples of the vertebrate fauna for examination for ectoparasites by the Laboratory of Acarology and to preserve specimens for identification. As a result sizeable collections of mammals, birds, and other vertebrates were obtained. In addition, ecological data were obtained (as time permitted), especially as an aid in studying the distribution of ectoparasites which affected man. In 1945, I spent eleven months in Micronesia; for most of this time I was stationed at Guam, the headquarters of the Unit, although one month was spent in the Palau Islands, two weeks were spent at Ulithi Atoll, and short stop-overs were made at Eniwetok and Kwajalein atolls. Other members of the laboratory staff visited Rota and Truk islands.

Subsequent to the field studies in the Pacific, I was sent to Washington and spent approximately eight months at the United States National Museum studying the collections of birds and preparing several reports for publication. In this period other material was studied, both in the United States National Museum and at the American Museum of Natural History, New York, and the literature dealing with the birds of Micronesia was explored and a bibliography of Micronesian birds was prepared. At the University of Kansas, I continued the bibliographic work, borrowed and studied some specimens, and completed accounts of the avifauna of Micronesia.

Under the account of each bird, all known references in the literature, which mention the scientific name of the bird and its distribution in Micronesia, are listed. The references are arranged as follows: (1) citation to the original description, and (2) citations to names in literature in the order of their first appearance. When a name is a pure synonym, it may be recognized as such by the fact that the type locality is given immediately following the citation. In compiling these references the writer made use of the invaluable work by Wiglesworth (1891) and of Utinomi's "Bibliographica Micronesia," made available through the translation by Fisher (1947). The arrangement of the families follows that of Peters (1931-1945) and Wetmore (1940).

Specimens examined are designated as to collection in which catalogued by the following abbreviations: USNM, the United States National Museum; AMNH, the American Museum of Natural History; MCZ, the Museum of Comparative Zoölogy; and KMNH, the University of Kansas Museum of Natural History. Average and extreme measurements of specimens are usually listed in tables; unless otherwise indicated, measurements are in millimeters, and are of adult specimens. The wings have been measured by flattening them on a ruler. Weights are in grams. Unless otherwise indicated, descriptions of the birds have been written by the author. Descriptions of shore birds are not given; for these the reader may refer to Mayr (1945a:28-47) where characters useful for identification of the birds in the field also are given. The writer is especially indebted to Dr. Ernst Mayr for making available the descriptions of Micronesian birds made by Miss Cardine Bogert, especially those dealing with color of the irides, feet, and bill. Color terms in quotation marks refer to those in Ridgway (1912).

In dealing with insular forms the criterion of intergradation as indicative of subspecies cannot be applied as it can in kinds of birds on the mainland which have geographically continuous distributions. Instead, degree of difference in combination with geographic position plus other factors such as degree of variation in the geographic races of the same species or a related species on continental areas are used in deciding whether two closely related kinds are subspecies or full species. Many kinds of birds in the islands are modified but little from island to island (examples, Rhipidura rufifrons, Aplonis opacus, Ducula oceanica, and Myzomela cardinalis), and can be treated as subspecies. Others show much variability from island to island and it is uncertain whether they should be treated as subspecies or as separate species (examples, Myiagra oceanica, Zosterops cinerea, Rukia, and possibly Acrocephalus luscinia). Decisions on generic status are equally difficult to make. In many cases the experience and judgment of the taxonomist may be the only criteria by which he can decide whether a bird is different enough to be considered as a distinct genus. This "human element" has caused some disagreement. Knowing whether the bird is to be considered as a distinct genus or instead merely as a species may not be as important as knowing its correct phylogenetic relationship. The circumstance that variation in these insular birds is in general less predictable than in mainland birds adds, I think, to the pleasure inherent in the classification of the variations.

First, I thank Commodore Thomas N. Rivers (MC) USNR, then commanding officer of NAMRU2, for the opportunity to join the Unit, for his interested cooperation in seeing that the plans for field trips were successful, and for his thoughtfulness in obtaining for me the orders for duty at the United States National Museum subsequent to our field investigations. Greatly appreciated also is the help rendered by my former colleagues of NAMRU2, including Dr. David H. Johnson, Dr. George W. Wharton, Dr. Aaron B. Hardcastle, Mr. Odis A. Muennik, Mr. L. P. McElroy, Mr. Charles O. Davison, Mr. Merle H. Markley, Mr. Walter L. Necker, Dr. Wilbur G. Downs, Dr. Bernard V. Travis, and Mr. E. W. Coleman. Other personnel, then stationed in Micronesia, who contributed data used in this report include: Dr. Joe T. Marshall, Jr., (who generously loaned some of the specimens taken by him in Micronesia), Dr. C. K. Dorsey, Dr. George Hensel, Mr. Tom Murray, Dr. Irwin O. Buss, Mr. James O. Stevenson, Dr. Wilfred D. Crabb, Mr. Herbert Wallace, and Dr. M. Dale Arvey. Authorities of the United States National Museum provided generously for using the collections there, and I am especially grateful to Dr. Alexander Wetmore, Dr. Herbert Friedman, and Mr. Herbert G. Deignan for their cooperation and assistance. Doctor Wetmore kindly made available many of the birds collected at Bikini during the atomic bomb experiments. Dr. Robert Cushman Murphy, Dr. Ernst Mayr, and Dr. Dean Amadon of the American Museum of Natural History made available the collections in their charge. Doctor Murphy allowed me to examine some of the heretofore unstudied collections of sea birds of the Whitney South Sea Expedition. Doctor Mayr generously helped me with taxonomic and evolutionary problems and made available to me some of his own unpublished taxonomic notes, the unpublished field accounts of Mr. William F. Coultas and a partly completed manuscript on the birds of Micronesia by Miss Cardine Bogert. Mr. James L. Peters generously loaned specimens from the Museum of Comparative Zoölogy. The use of unpublished field notes made by Mr. Larry P. Richards at Ponapé and Truk in 1947 and 1948 is also gratefully acknowledged. I am grateful also to my colleagues at the Museum of Natural History of the University of Kansas and would single out for special mention Dr. E. Raymond Hall who gave critical assistance with the manuscript, Drs. Edward H. Taylor and Herbert B. Hungerford who made helpful suggestions, and Mrs. Virginia Cassell Unruh who drew the distributional maps.

[ACCOUNTS OF THE KINDS OF BIRDS OF MICRONESIA]

Diomedea nigripes Audubon

Black-footed Albatross

Diomedea nigripes Audubon, Ornith. Biog., 5, 1839, p. 327. (Type locality, Pacific Ocean, lat. 30°44´N., long. 146°W.)

Diomedea fuliginosa Oustalet, Le Nat., 1889, p. 261 (Mariannes).

Diomedea nigripes Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris (3), 8, 1896, p. 51 (Agrigan); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne); Seale, Occ. Papers Bernice P. Bishop Mus. 1, 1901, p. 22 (Marianas); Safford, Osprey, 1902, p. 70 (Mariannes); idem, The Plant World, 7, 1904, p. 268 (Guam?); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 32 (Marriane); Peters, Check-list Birds World, 1, 1931, p. 43 (Marshalls); Hand-list Japanese Birds, rev., 1932, p. 188 (Marianas); Hand-list Japanese Birds, 3rd ed., 1942, p. 210 (Marianas); Mayr, Birds Southwest Pacific, 1945, p. 5 (Marshalls).

Geographic range.—North Pacific Ocean. Breeds on islands northwest of Hawaii. In Micronesia: Mariana Islands—Agrigan.

Characters.—A large oceanic bird with sooty-brown coloration; darker on nape, wings and tail; lighter on forehead, sides of head, and abdomen; area surrounding bill whitish; tail whitish at base; bill dark reddish-brown; feet black.

Remarks.—This albatross has been recorded from waters near the Mariana Islands. Quoy and Gaimard (1824:145) observed "albatross" between the Mariana and the Hawaiian Islands. The only actual specimens obtained from the islands were reported on by Oustalet (1896:51). These were eight Black-footed Albatrosses which were taken on the coast of Agrigan by Marche in December, 1888, and January, 1889. Oustalet gives the following measurements: total length, 680-785; wing, 485-525; tail, 180-225; tarsus, 80-90; culmen, 108-125. The specimens are apparently in the Paris Museum.

Peters (1931:43) lists the Marshall Islands as part of the range of D. nigripes.

In the period of the late war Gleise (1945:221) observed eight Short-tailed Albatrosses (D. albatrus Pallas) "off Saipan." Specimens of D. albatrus have not been taken in Micronesia. According to Austin (1948b:32) this albatross "is now virtually extinct," and this record may be questioned.

Puffinus pacificus chlororhynchus Lesson

Wedge-tailed Shearwater

Puffinus chlororhynchus Lesson, Traité d'Ornith., 8, 1931, p. 613. (Type is from Shark's Bay, West Australia.)

Puffinus sphenurus Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 299 (Mortlock).

Puffinus chlororhynchus Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 80 (Luganor?); Godman, Monogr. Petrels, pt. 2, 1908, p. 88 (Carolines); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 33 (Luganor or Ruk?).

Puffinus pacificus chlororhynchus Hand-list Japanese Birds, rev., 1932, p. 187 (Lukunor or Truk?, Kusaie); Hand-list Japanese Birds, 3d ed., 1942, p. 209 (Lukunor or Truk?, Kusaie).

Geographic range.—Breeds at the Seychelles, Australia, Lord Howe, Norfolk, and other islands in the Australian area. Ranges throughout most of the warmer parts of the Indian and Pacific oceans. In Micronesia: Mariana Islands—Guam; Caroline Islands—Lukunor or Truk?, Kusaie.

Characters.—A large shearwater with long wedge-shaped tail; upper parts sooty-brown with crown, neck, and wings darker and forehead paler; under parts paler than upper parts; bill dark; feet flesh-colored.

Remarks.—This shearwater was taken by Kubary either at Lukunor or at Truk in the Caroline Islands. At a later date, apparently between 1922 and 1932, the Japanese recorded the bird at Kusaie. In using this subspecific name, I am following the Hand-list of Japanese Birds (Hachisuka et al., 1932:187).

At Guam on August 10, 1931, Coultas obtained a male shearwater, which is tentatively placed in this subspecies. Its measurements are as follows: wing, 290; tail, 128; exposed culmen, 39; tarsus, 47. Coultas (field notes) writes that he was told by natives that petrels nest and roost on the high cliffs behind the city of Agaña on Guam. At sea south of the eastern Caroline islands, Coultas obtained five other birds which appear to be the same as the bird from Guam. All specimens are in the collections of the American Museum of Natural History.

Puffinus pacificus cuneatus Salvin

Wedge-tailed Shearwater

Puffinus cuneatus Salvin, Ibis, 1888, p. 353. (Type locality, Krusenstern Island==Ailuk, Marshall Islands, fide Fisher, Auk, 63, 1946, pp. 587-588.)

Puffinus cuneatus Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 80 (Krusenstern); Salvin, Cat. Birds British Mus., 25, 1896, p. 371 (Krusenstern); Godman, Monogr. Petrels, pt. 2, 1908, p. 76 (Marshalls).

Puffinus pacificus cuneatus Mathews, Birds Australia, 2, 1912, p. 84 (Marshall Group); Peters, Check-list Birds World, 1, 1931, pp. 55-56 (Krusenstern); Hand-list Japanese Birds, 3d ed., 1942, p. 209 (Krusenstern); Fisher, Auk, 63, 1946, pp. 587-588 (Ailuk).

Thyellodroma cuneata cuneata Mathews and Iredale, Ibis, 1915, p. 597 (Krusenstern); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 113 (Marshall Group).

Thyellodroma cuneata Oberholser, Auk, 34, 1917, p. 474 (Krusenstern).

Thyellodroma pacificia cuneata Mathews, Novit. Zool., 39, 1934, p. 186 (Caroline Islands).

Geographic range.—Pescadores east to the Hawaiian Islands and south to eastern Micronesia. In Micronesia: Marshall Islands—Ailuk.

Remarks.—Osbert Salvin received two specimens of this shearwater from H. J. Snow, who got them at the Krusenstern Islands in 1883. In describing them, Salvin (1888:353) comments that the locality is seemingly in the Marshall Islands at approximately 10°17´ N. and 190° W. This locality was confusing to Seebohm (1891:191) who thought it was between the Hawaiians and the Marshalls, while Hartert (1926:352) decided it was really Krusenstern Rocks in the Hawaiian Group. To clear the matter up, Fisher (1946:587-588) writes that Salvin was correct and suggests that the name of the island should be the better established one, Ailuk, rather than the little used one, Krusenstern.

P. p. cuneatus resembles P. p. chlororhynchus but is whiter on the underparts, especially the breast. These two subspecies are inseparable according to the twenty-fourth supplement to the American Ornithologists' Union Check-list of North American Birds (Auk, vol. 66, 1949:281).

Puffinus tenuirostris (Temminck)

Short-tailed Shearwater

Procellaria tenuirostris Temminck, Pl. Col., livr. 99, 1835, text to pl. 587. (Type locality, Seas north of Japan and shores of Korea.)

Puffinus tenuirostris tenuirostris Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam).

Puffinus tenuirostris Yamashina, Tori, 10, 1940, p. 677 (Kinajon, Marshall Islands); Hand-list Japanese Birds, 3d ed., 1942, p. 210 (Kinajon, Marshall Islands).

Geographic range.—Breeds in Tasmania, southeastern Australia, islands in Bass Straits, and Bounty Islands. Ranges north to the Bering Sea. In Micronesia: Mariana Islands—Guam?; Marshall Islands—Kinajon.

Character.—A rather large shearwater with short, rounded tail; upper parts sooty brown; underparts paler and more grayish than back; throat may be occasionally whitish; bill lead-gray; feet grayish, browner on outer side.

Remarks.—On migration this shearwater probably reaches most parts of Micronesia. It has been recently recorded by the Japanese at Kinajon in the Marshall Islands. Bryan (1936:15) includes this species as a "chance arrival" in his list of the birds of Guam.

Puffinus nativitatis Streets

Christmas Shearwater

Puffinus (Nectris) nativitatis Streets, Bull. U. S. Nat. Mus., 7, 1877, p. 29. (Type locality, Christmas Island, Pacific Ocean.)

Puffinus nativitatis Salvin, Cat. Birds British Mus., 25, 1896, p. 389 (Krusenstern); Lister, Proc. Zool. Soc. London, 1891, pp. 295-300 (Krusenstern); Godman, Monogr. Petrels, pt. 3, 1908, p. 153 (Marshalls).

Geographic range.—Breeds at Wake and Laysan Islands south to Christmas, Phoenix, Marquesas, Tuamotu, and Austral Islands. In Micronesia: Marshall Islands—Ailuk.

Characters.—Upper parts chocolate brown; underparts resemble upper parts but throat may be slightly grayer; bill and feet black. P. nativitatis resembles P. pacificus but is similar with black feet.

Remarks.—The only specimens of this bird known from Micronesia, are those taken in the spring of 1883 by H. J. Snow at Krusenstern (Ailuk) in the Marshall Islands. For two birds from this island in the collections of the British Museum, Godman (1908:154) gives the following measurements: wing, 9.6 and 10.0; tail, 3.35 and 3.4; culmen, 1.15 and 1.2; tarsus, 1.7 and 1.8; middle toe and claw, 2.0 and 2.1.

Puffinus lherminieri dichrous Finsch and Hartlaub

Dusky Shearwater

Puffinus dichrous Finsch and Hartlaub, Fauna Centralpolynesiens, 1867, p. 244. (Type locality, McKean Island, Phoenix Group.)

Puffinus dichrous Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 90, 108 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 6, 44 (Palau).

Puffinus opisthomelas var. minor Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 832 (Type locality, Pelew); Finsch, Journ. f. Ornith., 1872, p. 57 (Pelew).

Puffinus opisthomelas Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); Finsch, Journ. f. Ornith., 1870, p. 371 (Pelew).

Puffinus tenebrosus Pelzeln, Ibis, 1873, p. 47, fig. 1 (Type locality, unknown==Pelew Islands, ex Mathews); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 55 (Rota); Hartert, Novit. Zool., 5, 1898, p. 69 (Marianne); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 23 (Marianas?); Safford, The Plant World, 7, 1904, p. 268 (Guam).

Puffinus obscurus Finsch, Journ. Mus. Godeffroy, 12, 1876, pp. 18, 40 (Ponapé, Palau); idem, Proc. Zool. Soc. London, 1877, p. 786 (Palau); idem, Proc. Zool. Soc. London, 1877 (1878), p. 782 (Ponapé); idem, Journ. f. Ornith., 1880, pp. 295, 309 (Ponapé, Kuschai); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); idem, Ibis, 1881, p. 109 (Kuschai); idem, Ibis, 1881, pp. 113, 115 (Ponapé); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 353 (Ruk); Salvin, Ibis, 1888, p. 357 (Pelew); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 79 (Ruk, Ponapé, Pelew); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 54 (Saypan, Palaos); Salvin, Cat. Birds British Mus., 25, 1896, p. 382 (Carolines, Pelews); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 23 (Marianas?); Safford, Osprey, 1902, p. 70 (Marianas); Dubois, Syn. Avium, 2, 1904, p. 1031 (Pelew, Carolines); Godman, Monogr. Petrels, pt. 2, 1908, pp. 126, 127 (Pelew, Ruk, Ponapé).

Puffinus obscurus obscurus Hartert, Novit. Zool., 7, 1900, p. 10 (Ruk); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 32 (Saipan, Ruk, Ponapé, Pelew).

Puffinus lherminieri minor Mathews, Birds Australia, 2, 1912, p. 70 (Pelew, Carolines).

Puffinus assimilis minor Mathews, Syst. Avium Australasianarum, 1, 1927, p. 111 (Pelew).

Puffinus lherminieri dichrous Murphy, Amer. Mus. Novit., no. 276, 1927, p. 10 (Pelews, Carolines); Peters, Check-list Birds World, 1, 1931, p. 60 (Pelew); Yamashina, Tori, 7, 1932, p. 408 (Arakabesan); Hand-list Japanese Birds, rev., 1932, p. 188 (Saipan, Truk, Ponapé, Palaus); Hand-list Japanese Birds, 3rd ed., 1942, p. 209 (Saipan, Truk, Ponapé, Palau); Mayr, Birds Southwest Pacific, 1945, p. 10 (Carolines, Palaus); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 37 (Palau).

Alphapuffinus lherminieri minor Mathews, Novit. Zool., 39, 1934, p. 182 (Pelew Islands).

Puffinus obscura Bryan, Guam Rec., vol. 13, No. 2, 1936, p. 15 (Guam).

Geographic range.—Known from Phoenix, Nauru, Micronesia, and south to the Samoan, Society, Tuamotu, and Marquesas islands. In Micronesia: Mariana Islands—Guam, Rota, Saipan; Palau Islands—Babelthuap, Koror, Arakabesan; Caroline Islands—Truk, Ponapé, Kusaie.

Characters.—A small shearwater with upper parts sooty-black; under parts white except for sides of breast grayish and under tail-coverts blackish; bill blackish; feet yellowish, outer toe black.

Measurements.—Measurements of 17 adult birds (9 males, 7 females, 1 unsexed) from Micronesia (Palau, Truk, Ponapé, Kusaie) and 10 adult birds (6 males, 4 females) from the Phoenix Group (Enderbury, Canton) are listed in [table 14].

Table 14. Measurements of Puffinus lherminieri dichrous

Table 14. Measurements of Puffinus lherminieri dichrous

Specimens examined.—Total number, 72 (44 males, 19 females, 9 unsexed), as follows: Palau Islands, AMNH—exact locality not given, 64 (Oct., Nov., Dec.); Caroline Islands, AMNH—Truk, 4 (June 15, 16)—Ponapé, 3 (undated)—Kusaie, 1 (April 25).

Nesting.—The Dusky Shearwater in Micronesia nests in holes on high, and usually isolated, coral cliffs. Owston's collectors, according to Hartert (1900:10), found a nest with one egg at Truk on June 16. The nest was in a hole four feet deep in the side of a cliff. The egg is white and measures 42 × 35. Yamashina (1932a:408) records the taking of one egg at Arakabesan, Palau Islands, on May 26. Coultas (field notes) gives an interesting account of nesting activities of this shearwater at the Palau Islands. He found the bird nesting on small islands of the group from October to December, 1931; however, he states that the natives told him that the bird nests throughout the year. Land crabs and shearwaters were often found together in the same burrow. Apparently the adult birds did not remain in the burrow with the young during the day. At Kusaie, Coultas was told by the natives that the adult birds were caught by tying the mandibles of the young together. When the parent birds approached and hovered over the young birds expecting their mouths to open, the natives had the opportunity to strike them down with clubs. Coultas collected six downy nestlings at Palau in November and December.

Remarks.—The first published account of this shearwater in Micronesia was apparently by Kittlitz (1858, pt. 1:358) when he recorded his "Schwärzlicher Sturmvogel" at Kusaie, according to Wiglesworth (1891a:79). Finsch (1875:44 and 1881b:113, 115) studied specimens taken by Tetens, Heinsohn, and Kubary at the Palau Islands and those taken by Kubary at Ponapé. Earlier, Hartlaub (1868:832) used some of these specimens from the Palau Islands to describe his Puffinus opisthomelas var. minor, which was destined to be placed in synonymy (Murphy, 1927:10). Oustalet (1896:54, 55) recorded specimens taken by Marche at Saipan in May, 1887, and at Rota in July, 1888. Oustalet referred to them as P. obscuras and P. tenebrosus, respectively. T. W. Gulick obtained undated skins at Ponapé. Hartert (1900:10) reported on specimens taken by Owston's collectors at Truk. In 1931, Coultas with the Whitney South Sea Expedition took one shearwater at Kusaie and a series of 64 skins at the Palau Islands. He failed to find birds at Ponapé and wrote that their scarcity there may have been due to persistent hunting of them by the inhabitants of the island. The NAMRU2 party obtained no information concerning the birds at Guam, Rota, or Truk, but at the Palau Islands observed shearwaters at sea approximately 6 miles east of Babelthuap Island on September 2, 1945.

Murphy (1927:6-15) revised the shearwaters of the Puffinus lherminieri group, and recognized several subspecies. P. l. dichrous was assigned a range consisting of Micronesia, the Phoenix Islands, and Nauru Island. The breeding range of P. l. polynesiae was given as the Samoan, Society, Tuamotu and Marquesas islands. Color differences between the two subspecies are very slight, and he separated them on the basis of the length of the exposed culmen as follows: P. l. dichrous 22.6-27 (26) in P. l. polynesiae 25.5-30 (28.9). In other measurements they closely resembled one another. At the time of his study, Murphy did not have the shearwaters from Micronesia collected by Coultas and actually did not have a large series from these islands. On studying this new material, I find the length of the exposed culmen of 17 adult birds from Micronesia (including 12 from the Palaus) to be 26-30 (27.9). In comparison with Murphy's findings, my measurements of Micronesian birds fall almost midway between the measurements which he recorded as characteristic of P. l. dichrous (from the Phoenix Islands) and P. l. polynesiae. The intermediate position of the measurements of the Micronesian birds, together with the absence of other distinguishing characters, suggests that these shearwaters belong to only one subspecies which consists of a group of isolated and variable populations. Unless the old specific name, obscuras of Gmelin, is revived, the name for the entire group in Micronesia and Polynesia would be P. l. dichrous. I agree with Murphy that the Bonin form, P. l. bannermani, is a well-defined subspecies.

Pterodroma rostrata rostrata (Peale)

Tahiti Petrel

Procellaria rostrata Peale, U. S. Expl. Exp., 8, 1848, p. 296. (Type locality, Mountains about 6,000 feet on Tahiti, Society Islands.)

Procellaria desolata Pucheran, Voy. Pôle Sud, 3, 1853, p. 138 (des îles Carolines); Hartlaub, Journ. f. Ornith., 1854, p. 168 (Carolinen).

Procellaria (Aestrelata) desolata Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 55 (Caroline Islands).

Oestrelata rostrata Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 82 (Caroline Is.); Godman, Monogr. Petrels, pt. 3, 1908, p. 190 (Caroline Is.).

Pterodroma rostrata Kuroda, in Momiyama, Birds Micronesia, 1922, p. 33 (Carolines).

Pterodroma rostrata subsp. (?) Hand-list Japanese Birds, rev., 1932, p. 188 (Carolines); Hand-list Japanese Birds, 3d ed., 1942, p. 210 (Carolines).

Geographic range.—Known to breed on the Society and Marquesas Islands. In Micronesia: Caroline Islands—exact locality unknown.

Characters.—A large petrel with blackish-brown plumage except for belly and under tail-coverts white and throat, upper breast and flanks pale brown; bill black; legs yellowish; feet black. This oceanic bird differs from other petrels and shearwaters of Micronesia by the presence of a white abdomen in contrast with dark plumage on upper parts, throat, and breast.

Remarks.—A petrel which is referred to this subspecies has been taken once in Micronesia, by Hombron and Jacquinot in the Caroline Islands. It may be pointed out that the subspecies P. r. becki Murphy is known from the sea east of the Bismarck Archipelago and might range into Micronesian waters.

Pterodroma hypoleuca hypoleuca Salvin

Stout-billed Gadfly Petrel

Oestrelata hypoleuca Salvin, Ibis, 1888, p. 359. (Type locality, Krusenstern Island = Ailuk, Marshall Islands, fide Fisher, Auk., 63, 1946, pp. 587-588).

Oestrelata hypoleuca Salvin, Cat. Birds British Mus., 25, 1896, p. 409 (Krusenstern); Godman, Monogr. Petrels, pt. 3, 1908, p. 212 (Krusenstern).

Cookilaria hypoleuca hypoleuca Mathews, Syst. Avium Australasianarum, 1, 1927, p. 122, (Marshall Group).

Pterodroma leucoptera hypoleuca Hand-list Japanese Birds, rev., 1932, p. 188 (Marshalls); Hand-list Japanese Birds, 3d ed., 1942, p. 210 (Krusenstern); Fisher, Auk, 63, 1946, pp. 387-388 (Ailuk).

Pterodroma hypoleuca hypoleuca Mayr, Birds Southwest Pacific, 1945, p. 11 (Micronesia).

Geographic range.—Ranges from the Bonins east to the Hawaiians and south to Micronesia. In Micronesia: Marshall Islands—Ailuk.

Characters.—Upper parts grayish except for forehead whitish, crown and nape sooty-black; underparts whitish except for sides of breast sooty-black; legs and feet flesh color except for tips of toes and webs which are black.

Remarks.—In Micronesia, this petrel is known only from the type locality, Krusenstern or Ailuk, Marshall Islands. Fisher (1946: 587-588) has corrected the confusion regarding the exact position of this type locality.

Phaëthon aethereus mesonauta Peters

Red-billed Tropic-bird

Phaëthon aethereus mesonauta Peters, Occ. Papers Boston Soc. Nat. Hist., 5, 1930, p. 261. (Type locality, Swan Key, Almirante Bay, Panama.)

Phaeton aethereus Finsch, Ibis, 1880, pp. 329, 333, (Ratak Chain, Marshalls); idem, Journ. f. Ornith., 1880, p. 310 (Kuschai); idem, Ibis, 1881, p. 109 (Kuschai); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 73 (Kushai, Marshalls); Ogilvie-Grant, Cat. Birds British Mus. 26, 1898, p. 457 (Kushai, Marshalls); Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 34 (Kusaie, Marshall Islands).

Phaethon aethereus [?mesonauta] Hand-list Japanese Birds, rev., 1932, p. 187 (Kusaie, Marshalls); Hand-list Japanese Birds, 3d ed., 1942, p. 208 (Kusaie, Marshall Islands).

Geographic range.—Tropical parts of Atlantic and eastern Pacific from Cape Verde Islands west to Panama and Galapagos Islands. In Micronesia: Caroline Islands—Kusaie; Marshall Islands—Ratak Chain.

Characters.—Adult: A large, white sea bird with a long white tail; dorsal surface marked with blackish, transverse vermiculations; bill red; tarsus and foot flesh-colored with a yellowish hue, with plantar surface grayish. Immature: Resembles adults but dark transverse bars are broader; crown blacker; bill yellow.

Remarks.—No specimens have been examined. The Red-billed Tropic-bird is placed in the list of birds known from Micronesia on the basis of two observations by the German ornithologist, Otto Finsch. It has not been reported since his time, and may be considered as an unusual record for the area. I am following the Hand-list of Japanese Birds (Hachisuka et al., 1942:208) in assigning the bird to the subspecies, P. a. mesonauta.

Phaëthon rubricauda rothschildi (Mathews)

Red-tailed Tropic Bird

Scaeophaethon rubricauda rothschildi Mathews, Birds Australia, 4, 1915, p. 303. (Type locality, Laysan and Niihau.)

Phaeton rubricaudus Finsch, Journ. f. Ornith., 1880, p. 296 (Carolines); idem, Ibis, 1881, p. 115 (Ponapé).

Phaeton rubricauda Finsch, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 73 (Ruk, Ponapé, Marshalls).

Phaeton rubricauda Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 451 (Caroline Islands); Hartert, Novit. Zool., 7, 1900, p. 11 (Ruk); Hand-list Japanese Birds, rev., 1932, p. 187 (Pagan, Truk, Ponapé, Marshalls).

Scaeophaethon rubricauda Kuroda, in Momiyama, Birds Micronesia, 1922, p. 34 (Mariannes, Ruk, Ponapé, Marshalls).

Phaethon rubricauda rothschildi Yamashina, Tori, 7, 1932, p. 406 (Pagan); idem, Tori, 10, 1940, p. 676 (Maug).

Phaethon rubricaudus rothschildi Hand-list Japanese Birds, 3d ed., 1942, p. 209 (Maug, Pagan, Truk, Ponapé, Marshalls).

Geographic range.—Bonin and Hawaiian islands south to Micronesia. In Micronesia: Mariana Islands—Maug, Pagan; Caroline Islands—Truk, Ponapé; Marshall Islands—exact locality unknown.

Characters.—Adult: Long-tailed sea bird white with pinkish tint except for black lores and eye streak; black shafts on feathers of secondaries, flanks, and tail coverts; black bases on feathers of head; central tail feathers elongate with black shafts and bright red webs; bill orange-red with black nasal streak; tarsus and foot bluish-yellow, distal part blackish. Immature: Resembles adult but barred with black above; bill blackish.

Measurements.—Yamashina (1940:676) lists the measurements for seven adult birds from Maug in the northern Marianas as wing 304-319 and exposed culmen 55-62.

Nesting.—Yamashina (1932a:406) reports the taking of one egg at Pagan in the Marianas on February 15, 1931.

Remarks.—The Red-tailed Tropic Bird has been recorded from the Mariana, Caroline, and Marshall Islands. On the basis of our present knowledge it appears to be uncommon in most of Micronesia and may be established as a resident bird only in the northern Marianas, as shown by Yamashina (1932a:406 and 1940:676), Coultas obtained an immature male at 3° N and 158° E, which is at a point in the ocean south of the eastern Carolines. Possibly this bird and others obtained in the Carolines are representatives of the subspecies, P. r. melanorhynchos Gmelin, which is known from the Palmerston, Society and Turtle islands.

Phaëthon lepturus dorotheae Mathews

White-tailed Tropic Bird

Phoethon lepturus dorotheae Mathews, Austr. Avium. Rec., 2, 1913, p. 7. (Type locality, Queensland.)

Phaeton candidus Kittlitiz, Denkw. Reise russ. Amer. Micron. und Kamchat., 1, 1858, p. 382 (Ualan); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); Finsch, Journ. f. Ornith., 1872, p. 57 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 90, 114 (Pelew, Ualan); Finsch, Journ. Mus. Godeffroy, 1875, pp. 6, 47 (Palau); idem, Proc. Zool. Soc. London, 1877 (1878), p. 782 (Ponapé); idem, Journ. f. Ornith., 1880, pp. 296, 309 (Ponapé, Kuschai); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Schmeltz and Krause, Ethnogr. Abth. Mus., Godeffroy, 1881, pp. 281, 299, 330, 353 (Ponapé, Mortlock, Nukuor, Ruk); Finsch, Mitth. Ornith. Ver. Wien, 1884, p. 52 (Kuschai); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 73 (Pelew, Ruk, Luganor, Nukuor, Ponapé, Ualan, Marshalls); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 62 (Agrigan, Palaos, Ruk, Kushai, Marshalls); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne).

Phaeton flavirostris Finsch, Ibis, 1880, pp. 329, 333 (Ratak Chain); idem, Ibis, 1881, pp. 105, 109, 115 (Kuschai, Ponapé).

Phaethon candidus Salvadori, Ornith. Papuasia, 3, 1882, p. 426 (Pelews, Carolines, Marshalls); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 23 (Agrigan); Safford, Osprey, 1902, p. 70 (Mariannes); Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Pelew, Ponapé); Uchida, Annot. Zool. Japon., 9, 1918, pp. 489, 492 (Palau).

Phaëthon lepturus Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 453 (Pelew, Carolines, Marshalls); Hartert, Novit. Zool., 7, 1900, p. 10 (Ruk); Safford, The Plant World, 7, 1904, p. 268 (near Guam); idem, Contr. U. S. Nat. Herb., 9 1905, p. 80 (northern Marianas); Mayr, Birds Southwest Pacific, 1945, p. 17 (Palau); Strophlet, Auk, 63, 1946, p. 535 (Guam); Borror, Auk, 64, 1947, p. 416 (Agrihan); Stott, Auk, 64, 1947, p. 524 (Saipan).

Phaeton lepturus Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln).

Leptophaethon lepturus dorothea Mathews, Birds Australia, 4, 1915, p. 309 (Pelew).

Phaethan lepturus Cox, Island of Guam, 1917, p. 22 (northern Marianas).

Leptophaethon lepturus lepturus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 33 (Agrigan, Saipan, Pelew, Ruk, Luganor, Nukuor, Ponapé, Kusaie, Marshalls).

Phaethon lepturus dorotheae Yamashina, Tori, 7, 1932, p. 407 (Ponapé); Hand-list Japanese Birds, rev., 1932, p. 187 (Agrigan, Pagan, Saipan, Agiguan, Palaus, Truk, Luganor, Nukuor, Ponapé, Kusaie, Marshalls); Hand-list Japanese Birds, 3d ed., 1942, p. 209 (Agrigan, Pagan, Saipan, Agiguan, Babelthuap, Koror, Urukthapel, Angaur, Unusuto, Truk, Luganor, Nukuor, Ponapé, Kusaie, Namorik); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 38 (Guam, Peleliu, Ulithi, Truk).

Geographic range.—Islands in the southwestern Pacific area. In Micronesia: Mariana Islands—Agrigan, Pagan, Saipan, Agiguan, Rota, Guam; Palau Islands—Babelthuap, Koror, Urukthapel, Peleliu, Anguar, Unusuto; Caroline Islands Truk, Ulithi, Luganor, Nukuor, Ponapé, Kusaie; Marshall Islands—Namorik.

Characters.—Adult: White often with pinkish shade but lores and eye streak black; feathers of head, flanks and under tail-coverts with bases black; black on outer and subterminal part of inner webbing of primaries; black, subterminal coloring on scapulars and secondaries; black on shafts of elongated tail plumes; bill horn yellow, dark basally; tarsus dark yellow; feet blackish.

Immature: Resembles adult but upper parts barred with black, bill black on terminal part.

Measurements.—Measurements of adult birds from Micronesia are given in [table 15].

Weights.—The NAMRU2 party recorded weights of five adult males from Guam as 294 (267-321) grams.

Table 15. Measurements of Phaëthon lepturus from Micronesia

Table 15. Measurements of Phaëthon lepturus from Micronesia

Specimens examined.—Total number, 37 (22 males, 10 females, 5 unsexed), as follows: Mariana Islands, USNM—Guam, 5 (June 11, July 21); AMNH—Asuncion, 1 (June?); Palau Islands, USNM—Peleliu, 5 (Aug. 29, 31, Sept. 5, 6); AMNH—exact locality not given, 7 (Oct. 13, 26, Nov. 15, 23, Dec. 18); Caroline Islands, AMNH—Ponapé, 9 (Dec. 8, 9, undated)—Kusaie, 10 (March 1-8, April).

Nesting.—The NAMRU2 party observed nests of the White-tailed Tropic Bird at Peleliu in August and September, 1945. Several nests were seen in hollows of the Australian pine (Casuarina equisetifolia) between 20 and 30 feet above the ground. Birds could be seen in the nest hollows because the plumes of their long tail usually extended well out of the entrance. One nest was found in a dead tree in a battle-cleared area; others were observed in jungle habitat. Coultas observed nesting at Ponapé between November 1 and December 30, 1930, and found nests in the tops of trees and in hollow trees; a few were observed in holes in cliffs. Yamashina (1932a:407) records the taking of one egg at Ponapé on August 18, 1931. At Guam the NAMRU2 party found birds along the high cliffs which edge the beach. There was no evidence that they were nesting from May to July; nevertheless males taken in June had enlarged gonads. The bird is known to breed at Namorik in the Marshall Islands, according to the Hand-list of Japanese Birds (Hachisuka et al., 1942:209).

Food habits.—The NAMRU2 party found small fish in the stomachs of these birds taken at Peleliu.

Parasites.—Uchida (1918:489, 492) records the bird lice (Mallophaga), Colpocephalum epiphanes and Menopon eulasius, from the White-tailed Tropic Bird from Palau.

Remarks.—Birds taken in Micronesia differ only slightly from those from other areas in Oceania. Within Micronesia (see [table 15]) the birds from the Palaus have the shortest wing and shortest exposed culmen.

The White-tailed Tropic Bird appears more numerously in western and northern Micronesia than in the Marshall Islands. This distribution may be correlated with a preference for the "high" islands; especially those which have rocky cliffs, including Guam, Rota, Peleliu, Angaur, and Truk. Reports were received in 1945 that the birds were only infrequently seen at Ulithi, a low atoll. Stott (1947:524) observed birds flying into rocky crevices at Saipan on December 18. Gleise (1945:221) also recorded the bird in the vicinity of Saipan. Borror (1947:416) reports seeing birds at Agrigan on July 29, August 5 and 6, 1945. Coultas (field notes) found tropic birds common at Ponapé in November and December, 1930, in forested regions and along the cliffs. He made similar observations at Kusaie and Palau. At Ponapé and Palau, Coultas noted the use of the eggs, young and adults as food by the natives. At Palau the plumes are used in headdresses worn by the natives, the birds being taken with the blowgun.

Murphy (1936:807) states that the principal enemy of the White-tailed Tropic Bird at Bermuda is the introduced rat (Rattus rattus). Introduced rats, particularly Rattus mindanensis on Guam, may prey on the nesting birds. Baker (1946c:404) writes that this rat is a good climber and may spend considerable time in trees. The rat was trapped also in rough coral jungle at the edge of the cliffs, where tropic birds, Micronesian Starlings and other species, may have been nesting.

Little has been recorded concerning the post-breeding season wanderings of these tropic birds in Micronesia. They seemingly spend considerable time at sea, but whether they move as far from their breeding areas as do birds in the Atlantic, as reported by Murphy (1936:803), Baker (1947a:253) and others, is not known.

Murphy (1936:796) notes that the northward distribution of the tropic birds in the Atlantic is dependent on the warm currents of water. In the western Atlantic, the poleward-flowing, warm currents of the Gulf Stream allow for the northern extension of the range of these birds to Bermuda. In the eastern Atlantic, cool currents flowing toward the equator restrict the northern range. The same condition prevails in the eastern Pacific where warm current flowing toward the pole enable the birds to range north to the Bonins and other islands.

The three species of tropic birds known from Micronesia overlap very little in their ranges in this area. The White-tailed Tropic Bird has become firmly established in the western part of Micronesia, but there are only a few records from the extreme eastern part. The Red-tailed Tropic Bird appears to be resident only in the northern Marianas although it has been recorded in the Carolines and Marshalls. Interspecific competition may prevent considerable intermingling of breeding populations in Micronesia, or it may be that each species requires different ecologic conditions.

Sula dactylatra personata Gould

Masked Booby

Sula personata Gould, Proc. Zool. Soc. London, 1846, p. 21. (Type locality, North and northeast coasts of Australia = Raine Island.)

Sula cyanops Finsch, Ibis, 1880, p. 219 (Taluit); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 72 (Marshalls); Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 430 (Marshalls).

Parasula dactylatra personata Kuroda, in Momiyana, Birds Micronesia, 1922, p. 35 (Marshall Islands); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 232 (Marshall Islands).

Sula dactylatra personata Yamashina, Tori, 7, 1932, p. 407 (Medinilla); Hand-list Japanese Birds, rev., 1932, p. 187 (Medinilla, Marshall Islands); Hand-list Japanese Birds, 3d ed., 1942, p. 208 (Medinilla, Marshall Islands).

Geographic range.—Central and western Pacific from the Hawaiian Islands south to Australia, probably also in the Indian Ocean. In Micronesia: Mariana Islands—Medinilla; Marshall Islands—Jaluit?

Characters.—Adult: A large, white sea bird, with brown wings and tail; face dark blue; bill horn-colored with base orange-yellow in males and pink or light red in females; feet olive in males and lead gray in females.

Immature: Resembles adult, but head, wings, tail, chin and throat dark brown; some white mottling may be present on back and rump; bill dark; feet lead colored.

Nesting.—Yamashina (1932a:407) reports the taking of 12 eggs on February 19, 1931, at Medinilla Island in the Marianas.

Remarks.—No specimen has been examined by me from the area reported upon. Little is known regarding the distribution of the Masked Booby in Micronesia. It is found on the island groups which surround Micronesia and future field observations probably will add to our knowledge of its occurrence in this area. It is known to be resident only in the northern Marianas.

Sula sula rubripes Gould

Red-footed Booby

Sula rubripes Gould, Syn. Birds Australia, pt. 4, 1838, app., p. 7. (Type locality, New South Wales = Raine Island.)

Pelecanus piscator Kittlitz, Obser. Zool., in Lutké, Voy. "Le Séniavine," 3, 1836, pp. 296, 299 (Lougounor = Lukunor); idem, Denkw. Reise russ. Amer. Micron. und Kamchat., 1, 1858, p. 351 (Lugunor).

Dysporus piscator Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 831 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelews); idem, Proc. Zool. Soc. London, 1872, p. 90 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 6, 47 (Palau).

Sula piscatrix Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 72 (Pelew, Luganor); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 64 (Rota, Palaos, Carolines); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne); Safford, Osprey, 1902, p. 70 (Rota); idem, The Plant World, 7, 1904, p. 267 (Guam); idem, Contr. U. S. Nat. Herb., 9, 1905, p. 80 (Guam); idem, Guam, 1912, p. 19 (Guam); Cox, Island of Guam, 1917, p. 22 (Guam).

Sula piscator Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 432 (Pelew); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 24 (Guam).

Piscatrix sula rubripes Kuroda, in Momiyana, Birds Micronesia, 1922, p. 34 (Pelew, Luganor, Rota).

Sula sula rubripes Hand-list Japanese Birds, rev., 1932, p. 185 (Medinilla, Saipan, Rota, Palau, Lukunor, Likieb); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Yamashina, Tori, 10, 1940, p. 676 (Maug, Bikar); Hand-list Japanese Birds, 3d ed., 1942, p. 208 (Maug, Medinilla, Saipan, Rota, Palau, Lukunor, Bikar, Likieb).

Geographic range.—Indian Ocean east to central Pacific islands. In Micronesia: Mariana Islands—Maug, Medinilla, Saipan, Rota; Palau Islands—exact locality unknown; Caroline Islands—Lukunor; Marshall Islands—Bikar, Likieb, Bikini, Eniwetok.

Characters.—Adult: A large sea bird with plumage of variable color, mainly white or partly buff with black primaries and black-tipped secondaries, or grayish or brownish with white or grayish tail; throat blackish; face blue or green; bill bluish and lighter at tip; legs and feet red.

Immature: Resembles adult, but often wholly brownish, lighter ventrally; bill blackish; feet yellowish red. Immature resembles that of S. leucogaster.

Nesting.—Morrison obtained a male nestling at Bikini on May 3, 1946.

Specimens examined.—Total number, 10 (3 males, 7 females) from Marshall Islands, USNM—Bikini (April 28, May 1, 2, 3).

Remarks.—The writer saw several birds approximately 20 miles east of Eniwetok on January 7, 1945. Morrison obtained a series of birds at Bikini in April and May, 1946. Murphy (1936:861-870) presents a wealth of information concerning the bird. He points out the need for a better understanding of the plumages of the adult birds and gives evidence that the birds of different colors may occur within the same population. He describes the Red-footed Booby as nesting in trees and shrubs. This type of nesting environment is present at many of the islands in Micronesia.

Sula leucogaster plotus (Forster)

Brown Booby

Pelecanus Plotus Forster, Descr. Anim., ed. Licht., 1844, p. 278. (Type locality Near New Caledonia.)

Dysporus sula Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 831 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); idem, Proc. Zool. Soc. London, 1872, p. 90 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 6, 47 (Palau); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Hartert, Novit. Zool., 7, 1900, p. 11 (Ruk).

Sula fusca Finsch, Ibis, 1880, p. 218 (Taluit).

Sula leucogastra Salvadori, Ornith. Papuasia, 3, 1882, p. 423 (Pelew, Carolinis); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 72 (Pelew, Ruk, Marshalls); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 63 (Palaos, Mariannes, Marshalls, Carolines); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne).

Sula sula Ogilvie-Grant, Cat. Birds British Museum, 26, 1898, p. 436 (Asuncion, Pelew); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 24 (Guam); Safford, Osprey, 1902, p. 66 (Mariannas); idem, The Plant World, 7, 1904, p. 267 (Guam); idem, Contr. U. S. Nat. Herb., 9, 1905, p. 80 (Guam); idem, Guam, 1912, p. 19 (Guam); Prowazek, Die deutschen Marianen, 1913, p. 100 (Marianen); Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Marianne); Cox, Island of Guam, 1917, p. 22 (Guam); Uchida, Annot. Zool. Japon., 9, 1918, pp. 487, 493 (Sea off Mariana Islands).

Sula leucogaster plotus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 34 (Pelew, Ruk, West Faiu, Uracas, Saipan, Marshalls); Yamashina, Tori, 7, 1932, p. 407 (Medinilla); Hand-list Japanese Birds, rev., 1932, p. 185 (Uracas, Pagan, Medinilla, Saipan, Truk, West Fayu, Grimes, Marshalls); Hand-list Japanese Birds, 3d ed., 1942, p. 208 (Uracas, Pagan, Medinilla, Saipan, Grimes, West Fayu, Truk, Marshalls); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 41 (Rota, Guam, Truk).

Geographic range.—Throughout tropical Pacific area and south to Australia. In Micronesia: Mariana Islands—Asuncion, Uracas, Pagan, Medinilla, Saipan, Rota, Guam; Palau Islands—exact locality unknown; Caroline Islands—Grimes, West Fayu, Truk, Kusaie; Marshall Islands—Jaluit, Eniwetok.

Characters.—Adult: A heavy sea bird dark brown except for white lower breast, belly, under tail, and auxillars; bill heavy and light bluish; face, gular pouch and feet greenish yellow.

Immature: Resembles adult, but lower breast, belly and under tail mottled with brown; feet light yellow.

Measurements.—Two adult males (Rota, Guam) measure: wing 386, 408; tail 194; exposed culmen 93, 98; tarsus 45, 49; two adult females (Rota, Kusaie): wing 380, 487; tail 193, 217; exposed culmen 94, 99; tarsus 45, 50.

Weights.—The author (1948:41) records one immature female from Rota weighing 1042 grams.

Specimens examined.—Total number, 6 (3 males, 3 females), as follows: Mariana Islands, USNM—Rota, 3 (Oct. 24); AMNH—Guam, 1 (July 23); Palau Islands, AMNH—exact locality not given, 1 (Dec. 1); Caroline Islands, AMNH—Kusaie, 1 (April 19).

Nesting.—Few records have been published concerning nesting of the Brown Booby in Micronesia. Yamashina (1932a: 407) reports the taking of 12 eggs at Medinilla in the Mariana Islands on February 19, 1931. At Palau, Coultas (field notes) obtained reports that the bird nests at Kiangat, a small islet north of Babelthuap.

Parasites.—Uchida (1918:487, 493) obtained bird lice (Mallophaga), Menopan brevipalpe and Lipeurus potens, from the Brown Booby from the "sea off Mariana Islands."

Remarks.—The Brown Booby has not been found abundantly by observers in the Micronesian area. Coultas and Kubary, who spent considerable time in this region, observed the bird at only a few of the islands. Probably the bird does not nest abundantly in Micronesia, although small colonies may be present. The NAMRU2 party observed a flock of twelve brown boobies on high cliffs at Taipingot Peninsula at Rota on October 24, 1945. Birds were seen also at Guam in May, July and November, 1945, and at Truk in December of the same year. Coultas obtained a single specimen at Kusaie; the natives told him that it was not a resident of the island. The writer observed several Brown Boobies approximately twenty miles east of Eniwetok in the Marshall Islands on January 7, 1945. These were in the company of other sea birds.

Phalacrocorax melanoleucus melanoleucus (Vieillot)

Little Pied Cormorant

Hydrocorax melanoleucos Vieillot, Nouv. Dict. Hist. Nat., 8, 1817, p. 88. (Type locality, "Australasie," restricted to New South Wales.)

Carbo melanoleucus Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); idem, Proc. Zool. Soc. London, 1872, pp. 90, 114 (Pelew).

Graculus melanoleucus Finsch, Journ. Mus. Godeffroy, 8, 1875, p. 48 (Pelew).

Microcarbo melanoleucus Salvadori, Ornith. Papuasia, 3, 1882, p. 410 (Pelew); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 72 (Pelew).

Phalacrocorax melanoleucus Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 398 (Pelew); Nehrkorn, Kat. Eiers., 1899, p. 235 (Palau); Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Pelew); Uchida, Annot. Zool. Japon., 9, 1918, p. 486 (Palau).

Ph[alacrocorax] melanoleucos Reichenow, Die Vögel, 1, 1913, p. 127 (Palauinseln).

Microcarbo melanoleucus melanoleucus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 35 (Pelew).

Microcarbo melanoleucus melvillensis Mathews, Syst. Avium Australasianarum, 1, 1927, p. 228 (Pelew); Hand-list Japanese Birds, rev., 1932, p. 186 (Babelthuap, Koror).

Haliëtor melanoleucos melanoleucos Peters, Check-list Birds World, 1, 1931, p. 93 (Pelew).

Phalacrocorax melanoleucus melanoleucus Mayr, Amer. Mus. Novit., no. 486, 1931, p. 5 (Pelew); Amadon, Amer. Mus. Novit., no. 1175, 1942, p. 2 (Palau); Mayr, Birds Southwest Pacific, 1945, pp. 50, 284 (Palau, Marianas); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 41 (Palau).

Phalacrocorax melanoleucos melvillensis Hand-list Japanese Birds, 3d ed., 1942, p. 207 (Pagan, Babelthuap, Koror, Angaur).

Geographic range.—Tasmania, Australia, Lesser Sunda north through Melanesia to Palau Islands. In Micronesia: Palau Islands—Babelthuap, Koror, Garakayo, Ngabad, Peleliu, Anguar.

Characters.—Adult: A small cormorant with upper parts black with dull greenish gloss; under parts white except vent and under tail-coverts which are sooty-black.

Measurements.—The author (1948: 41) gives the following measurements of two adult females from Peleliu: wing, 220 and 222; tail, 153 and 157; culmen from notch of suture between maxilla and quadratojugal bones, 35 and 36.

Specimens examined.—Total number, 15 (1 male, 12 females, 2 unsexed), as follows: Palau Islands, USNM—Peleliu, 6 (Aug. 27, Sept. 7, 10, 16); AMNH—exact locality not given, 9 (Nov. part).

Nesting.—Nehkorn (1899:235) recorded eggs taken at Palau. Some of the specimens obtained by Coultas in November, 1931, had swollen gonads. The author found no evidence of nesting in August and September, 1945, in the southern Palaus.

Food habits.—The author (1948: 41) found small fish in the stomachs of birds taken in August and September. The contents of each stomach averaged approximately 3 cc. in volume.

Parasites.—Uchida (1918:486) found the bird louse (Mallophaga), Lipeurus subsetosus, on the Little Pied Cormorant from Palau.

Remarks.—The Palaus mark the northernmost point of range of the Little Pied Cormorant. It does not occur in the Philippines and must have reached Palau from the New Guinea region. It is unknown at Yap and other "high" islands in the Carolines. A sight record of this species at Pagan in the northern Marianas, made by Orii and reported in the Hand-list of Japanese Birds (Hachisuka et al., 1942:207), may be questioned. Amadon (1942:1) has studied the races of this species and points out that there is little geographic variation in the species; it is divisible into three subspecies. One of these is confined to New Zealand. Another occurs only on Rennell Island, Solomons. The six specimens taken by the NAMRU2 party at Peleliu included only two adults, whose measurements are within the range of those studied by Amadon.

The NAMRU2 party found the birds numerously in the southern Palaus in 1945. Birds were concentrated in the areas of mangrove swamp and on the tidal flats. In August and September, they were observed frequently in groups of 10 to 15, either sitting on the ground or perched on low mangroves or dead snags sunning themselves. Coultas (field notes) received reports that they nested at a freshwater lake on the "main island" (Babelthuap?)

Ripley (1948) reports the occurrence of "about a dozen anhingas (presumably Anhinga melanogaster)" at Babelthuap on 12 November 1946.

Fregata minor minor (Gmelin)

Pacific Man-o'-War

Pelecanus minor Gmelin, Syst. Nat., 1, pt. 2, 1789, p. 572. (No type locality = Christmas Island, Indian Ocean.)

Pelecanus aquila? Quoy and Gaimard, Voy. "Uranie," Zool., 1824, p. 154 (Carolines).

Pelecanus aquilus? Lesson, Man. d'Ornith., 2, 1828, p. 354 (Carolines).

Atagen aquilus Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 61 (Ladrone or Marian Islands).

Tachypetes aquila Finsch, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Hartert, Novit. Zool., 7, 1900, p. 11 (Ruk); Prowazek, Die deutschen Marianen, 1913, p. 100 (Marianen).

Tachypetes aquilus Finsch, Ibis, 1880, p. 333 (Taluit); idem, Journ. f. Ornith., 1880, pp. 296, 310 (Ponapé, Kuschai); idem, Ibis, 1881, pp. 109, 115 (Kuschai, Ponapé); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, pp. 299, 353 (Mortlock, Ruk).

Fregata aquila Salvadori, Ornith. Papuasia, 3, 1882, p. 403 (Carolines, Marshalls); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, (1890-1891), p. 71 (Ruk, Luganor, Ponapé, Ualan, Marshalls); Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 443 (Carolines, Marshalls); Finsch, Deut. Ver. zum Schultze der Vogelwelt, 25, 1900, p. 452 (Ponapé, Kuschai, Marshalls); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 24 (Guam); Safford, The Plant World, 7, 1904, p. 267 (Guam); Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln); Safford, Contr. U. S. Nat. Herb., 9, 1905, p. 80 (Guam); Cox, Island of Guam, 1917, p. 22 (Guam).

Fregata aquila palmerstoni Kuroda, in Momiyama, Birds Micronesia, 1922, p. 35 (Carolines, Marshalls).

Fregata minor peninsulae Mathews, Syst. Avium Australasianarum, 1, 1927, p. 233 (Carolines, Marshalls); Peters, Check-list Birds World, 1, 1931, p. 96 (Carolines?, Marshalls?).

Fregata minor palmerstoni Hand-list Japanese Birds, rev., 1932, p. 186 (Yap, Faraulep, Truk, Lukunor, Ponapé, Kusaie, Namu, Likieb); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Yamashina, Tori, 10, 1940, p. 676 (Maug, Bikar).

Fregata minor minor Hand-list Japanese Birds, 3d ed., 1942, p. 207 (Maug, Yap, Faraulep, Truk, Lukunor, Ponapé, Kusaie, Namu, Bikar, Likieb).

Fregata minor Borror, Auk, 64, 1947, p. 416 (Agrihan).

Geographic range.—Eastern Indian Ocean to western Pacific Ocean. Limits of range not certainly known. In Micronesia: Mariana Islands—Agrigan, Maug, Saipan, Guam; Caroline Islands—Yap, Faraulep, Truk, Lukunor, Ponapé, Kusaie; Marshall Islands—Namu, Bikar, Likieb, Kwajalein, Bikini.

Characters.—Adult male: Large sea bird with deeply forked tail; blackish but wing-coverts paler; head and back glossy purple and blue; breast lighter than belly. Adult female: Resembles adult male, but head blacker; chin and throat grayer; breast more whitish. Immature: Resembles adult, but head and throat whitish washed with buff; breast dark brown; belly whitish.

Measurements.—Two adult males measure: wing, 572; tail, 354, 396; exposed culmen, 98, 103; two adult females; wing, 583, 604; tail, 365; exposed culmen, 119, 127. These four specimens are from Bikini.

Specimens examined.—Total number, 10 (3 males, 7 females), from Marshall Islands, USNM—Bikini (March 11, 22, 29, 30, April 13, 29, May 3, 14).

Remarks.—The systematic position of the subspecies of Fregata minor in the Pacific area is not well established. I am following the committee who prepared the Hand-list of Japanese Birds (Hachisuka et al., 1942:207) in using the name F. m. minor, although a thorough study may show that these birds have closer relationships to one of the other subspecies of the Pacific area.

Fregata minor has been reported only occasionally in the Marianas and probably is not resident there. Borror (1947:416) reports the bird at Agrihan on August 11, 1945, and Seale (1901:24) mentions one taken at Guam in November, 1889. No records are known from the Palaus. In the Carolines the birds are probably resident, especially in the eastern part. In the Marshalls the species is a conspicuous member of the bird colonies on the coral atolls. Wallace (field notes) observed two birds at Loi Island in Kwajalein Atoll on May 7, 1944. Morrison obtained ten specimens at Bikini in the period from March through May in 1946.

Fregata ariel ariel (Gray)

Least Man-o'-War

Atagen (sic) Ariel Gray, Gen. Birds, 3, 1845, col. pl. [185]. (Type locality, Raine Island, Queensland.)

Pelecanus minor Lesson, Traite d'Ornith., 1831, p. 607 (Mariannes, Carolines).

Tachypetes minor Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 831 (Mackenzie Group); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, p. 90 (Uap); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 123 (Yap).

Fregata minor Salvadori, Ornith. Papuasia, 3, 1882, p. 405 (Mariannes, Mackenzie); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 71 (Uap, Ngoli or Matelotas).

Tachypetes aquila var. minor Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 65 (Rota, Carolines, Marshalls); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne).

Fregata ariel Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 447 (Marianas, Carolines); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 25 (Guam?); Safford, Osprey, 1902, p. 70 (Marianas); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam).

Fregata ariel ariel Mathews, Birds Australia, 4, 1914-15, p. 285 (Carolines, Marshalls); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 36 (Yap, Ngoli, Rota); Hand-list Japanese Birds, rev., 1932, p. 186 (Rota, Yap, Ngulu, Uluthi); Hand-list Japanese Birds, 3d ed., 1942, p. 208 (Rota, Yap, Ngulu, Uluthi).

Geographic range.—China coast and Philippines south to Australia and east to Pacific islands. In Micronesia: Mariana Islands—Guam?, Rota; Caroline Islands—Yap, Ngulu, Ulithi.

Characters.—Adult male: Resembles F. m. minor, but smaller and blacker with upper parts lustrous greenish-blue and white patch on lower flank.

Adult female: Resembles adult male, but browner with paler nape and white breast. Immature: Resembles adult, but with head, chin, throat, and belly white washed with rufous.

Remarks.—Like F. minor, the Least Man-o'-War has not been observed often in Micronesia. Marche obtained one female at Rota in June, 1888. D. H. Johnson saw a bird thought to be of this species at Agfayan Bay, Guam, on 4 June 1945. Records from the western Carolines are few. There are no reports of this bird from the Palaus and the Marshalls. It may breed on some of the atolls in the Carolines.

The two species of man-o'-war birds may be difficult to distinguish in the field. The smaller size of Fregata ariel is perhaps the most useful character although it may be easily recognized also by the presence of the white flank patch, if it can be observed.

Both of the species of Fregata discussed in this report have representatives in the Atlantic, Indian and Pacific oceans. Murphy (1936:920) has shown that the man-o'-war birds are able to cross the Isthmus of Panamá between the Pacific and Atlantic oceans. This route may also be the means of dispersal for other species. The irregular distribution of these birds as well as of other sea birds in the oceanic islands of the Pacific may be caused by their remaining over waters which contain preferred foods and their avoidance of waters which lack preferred foods.

Butorides striatus amurensis Schrenck

Amur Green Heron

Ardea (Butorides) virescens var. amurensis Schrenck, Reise Amur Lande, 1, pt. 2, 1860, p. 441. (Type locality, Amurland.)

Butorides striatus javanicus Hand-list Japanese Birds, rev., 1932, p. 183 (Koror, Babelthuap).

Butorides striatus amurensis Hand-list Japanese Birds, 3d ed., 1942, p. 204 (Babelthuap, Koror); Mayr, Birds Southwest Pacific, 1945, p. 302 (Palau).

Geographic range.—Breeds in northeastern Asia, China, Japan, Bonins. Winters south to Philippines and Malaysia. In Micronesia: Palau Islands—Babelthuap, Koror.

Specimens examined.—Total number, 2 females, from Palau Islands, AMNH—exact locality not given (Nov. 13, Dec. 17-18).

Remarks.—The Amur Green Heron has been recorded as a winter visitor to the Palau Islands. Two females taken by Coultas in November and December, 1931, are immature. He comments (field notes) that he saw, in all, three birds in taro patch and mangrove swamp habitat.

Bubulcus ibis coromandus (Boddaert)

Cattle Egret

Cancroma Coromanda Boddaert, Table Pl. enlum., 1783, p. 54. (Type locality, Coromandel.)

Ardeola ibis coromanda Hand-list Japanese Birds, rev., 1932, p. 183 (Koror).

Bubulcus ibis coromandus Hand-list Japanese Birds, 3d ed., 1942, p. 204 (Koror, Babelthuap); Mayr, Birds Southwest Pacific, 1945, p. 302 (Palau).

Geographic range.—India, Ceylon, east to China and Japan and south to Malaysia. In Micronesia: Palau Islands—Babelthuap, Koror.

Remarks.—The Japanese ornithologists have recorded the Cattle Egret from Babelthuap and Koror in the Palau Islands. It is a winter migrant.

Egretta intermedia intermedia (Wagler)

Plumed Egret

Ardea intermedia Wagler, Isis, 1829, p. 659. (Type locality, Java.)

Egretta intermedia intermedia Hand-list Japanese Birds, rev., 1932, p. 183 (Koror); Hand-list Japanese Birds, 3d ed., 1942, p. 203 (Koror); Mayr, Birds Southwest Pacific, 1945, p. 302 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 42 (Rota, Guam, Peleliu, Angaur, Ulithi).

Egretta intermedia Wharton and Hardcastle, Journ. Parasitology, 32, 1946, pp. 306, 310 (Ulithi); Baker, Ecol. Monogr., 16, 1946, p. 408 (Guam).

Geographic range.—India and Ceylon east to Malaysia, Philippines, China and Japan. In Micronesia: Mariana Islands—Saipan, Rota, Guam; Palau Islands—Koror, Peleliu, Angaur; Caroline Islands—Ulithi.

Characters.—Adult: A large white heron with green facial skin; black legs, feet and toes. In breeding plumage: Head with crest; neck and back with ornamental plumes; bill black. Winter plumage: Without crest or plumes; bill yellow with blackish tip. Immature: Resembles adult in winter plumage, but feathers soft and downy.

Measurements.—Five males from Saipan, Rota, Guam, and Angaur measure: wing, 295-321 (308); tail, 112-127 (119); culmen, 85-87 (87); tarsus, 111-118 (114); three females from Saipan, Ulithi, Angaur: wing, 294-301 (297); tail, 101-116 (110); culmen, 77-83 (80); tarsus, 108-115 (107).

Weights.—The author (1948:43) records the weights of two males from Guam as 445 and 463.

Specimens examined.—Total number, 8 (5 males, 3 females), as follows: Mariana Islands, USNM—Saipan, 2 (Sept. 29, Oct. 2)—Rota, 1 (Oct. 31)—Guam, 2 (June 13); Palau Islands, USNM—Angaur, 2 (Sept. 21); Caroline Islands, USNM—Ulithi, 1 (Aug. 15).

Food habits.—The NAMRU2 party found grasshoppers, other insects, spiders and lizards in the stomachs of egrets taken at Guam, Ulithi, and Angaur.

Parasites.—Wharton and Hardcastle (1946:306, 310) obtained the chiggers (Acarina), Neoschöngastia egretta and N. ewingi, from this egret from Ulithi.

Remarks.—The NAMRU2 party obtained Plumed Egrets at Rota, Guam, Ulithi, and Angaur in 1945. Previously, the only known record was from Koror, as reported in the Hand-list of Japanese Birds (Hachisuka et al., 1932:183). In addition, in 1945, Joe T. Marshall, Jr., obtained two birds at Saipan, and Gleise (1945:220) reported seeing "white herons" at Tinian, which probably were egrets. Gleise estimated the number of these birds at Tinian to be fifty; he found them in swampy areas. At Rota, the NAMRU2 party found a flock of sixteen birds in a cultivated field on October 31. At Guam, egrets were first observed on February 25, 1945, when a flock of fourteen was found in a fallow rice paddy near Piti. This flock remained in this area and were seen occasionally until as late as June 13, when two were taken as specimens. A short time later (June 30) the entire area was cleared for military use and the birds were seen no more. At Agfayan Bay a flock of sixteen birds was found on the beach on July 24 and on August 6. These birds kept apart from Reef Herons which were also in the area. In June, 1946, M. Dale Arvey observed egrets in swamps along the Ylig River at Guam. At Ulithi Atoll, three egrets were seen on August 15 at Potangeras Island, feeding in grassy areas adjacent to the beach. In the southern Palaus, the NAMRU2 party found egrets in August and September on tidal flats and open grasslands at Peleliu and Angaur. At Peleliu, a flock of twenty-five birds was seen on September 8 and a flock of eight birds on September 16. At Angaur approximately twenty birds were seen in groups of five or more on September 21. These birds, unlike the Reef Herons, preferred grasslands to beach areas for feeding and were usually seen in sizeable flocks.

There was no evidence of breeding; specimens examined were either immatures or adults in winter plumage, since they had yellow bills tipped with black and slight or no development of ornamental plumes. Birds taken at Guam in June and at Angaur in September had no ornamental plumes, while birds taken at Ulithi in August, at Saipan in September and October, and at Rota in late October show some development of the back plumes. Wharton and Hardcastle (1946:306) found the same species of chigger on Plumed Egrets from Ulithi and from Okinawa in the Riu Kiu Islands. The NAMRU2 party observed the birds in Micronesia from February until October in 1945, and although the Plumed Egret may be considered as merely a visitor to Micronesia, it would not be surprising to find nests there. The fact that several new distributional records were obtained for Micronesia in 1945 may indicate that the birds have been overlooked by ornithologists in the past or that the birds are increasing the breadth of their winter (or breeding?) range.

Demigretta sacra sacra (Gmelin)

Reef Heron

Ardea sacra Gmelin, Syst. Nat., 1, pt. 2, 1789, p. 640. (Type locality, Tahiti.)

Ardea jugularis Kittlitz, Observ. Zool., in Lutké, Voy. "Le Séniavine," 3, 1836, pp. 286, 299, 304 (Ualan, Lougounor, Guahan); Hartlaub, Journ. f. Ornith., 1854, p. 167 (Mariannen); Kittlitz, Denkw. Reise russ. Amer. Micron. und Kamchat., 2, 1858, p. 63 (Ualan); Pelzeln, Reise "Novara," Vögel, 1865, pp. 118, 162, 120, 121 (Puynipet, Ualan).

Ardea (Herodias) atra Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 48 (Ladrone or Marian Islands, Caroline Islands).

Ardea sacra Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 831 (Matelotas Islands); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 8, 118 (Pelews); Finsch and Hartlaub, Journ. f. Ornith., 1870, p. 137 (Pelews, Matelotas); Gray, Hand-list Birds, 3, 1871, p. 28 (Marian, Carolines, Pelews, Matelotas); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 104 (Pelew, Uap, Ualan); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 123 (Yap); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 32 (Palau); idem, Journ. Mus. Godeffroy, 12, 1876, pp. 18, 38 (Ponapé, Ualan); idem, Proc. Zool. Soc. London, 1877 (1878), p. 781 (Ponapé); idem, Journ. f. Ornith., 1880, pp. 294, 306 (Ponapé, Kuschai); idem, Ibis, 1880, pp. 220, 330, 332 (Taluit); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); idem, Ibis, 1881, pp. 105, 106, 109, 115 (Kushai, Ponapé); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, pp. 299, 353 (Mortlocks, Ruk); Finsch, Mitth. Ornith. Ver. Wien, 1884, p. 51 (Jaluit, Kuschai); Oustalet, Le Nat., 1889, p. 261 (Mariannes); Wiglesworth, Ibis, 1893, p. 211 (Marshalls); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 36 (Guam, Marshalls, Palaos, Carolines); Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall-Inseln).

Demiegretta sacra Salvadori, Ornith. Papuasia, 3, 1882, p. 348 (Marshalls, Ualan, Ponapé, Ruck, Pelew, Mariannis); Wiglesworth, Abhandl. Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 67 (Marianne, Pelews, Luganor, Ruk, Ponapé, Ualan, Taluit); Hartert, Novit. Zool., 5, 1898, p. 64 (Saipan); Sharpe, Cat. Birds British Mus., 26, 1898, p. 137 (Pelew, Carolines, Marshalls); Hartert, Novit. Zool., 7, 1900, p. 11 (Ruk); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 29 (Guam); Safford, Osprey, 1902, p. 67 (Marianas); idem, The Plant World, 7, 1904, p. 266 (Guam); Kuroda, Avifauna Riu Kiu, 1925, p. 129 (Micronesia); Bryan, Guam, Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Bequaert, Occ. Papers Bernice P. Bishop Mus., 16, 1941, p. 266 (Kusaie).

Demigretta sacra Safford, Contr. U. S. Nat. Herb., 9, 1905, p. 79 (Guam); Prowazek, Die deutschen Marianen, 1913, p. 101 (Saipan, Tinian); Cox, Island of Guam, 1917, p. 21 (Guam); Bequaert, Mushi, 12, 1939, p. 81 (Kusaie); Warton, Ecol. Monogr., 16, 1946, p. 175 (Guam); Warton and Hardcastle, Journ. Parasitology, 32, 1946, pp. 306, 316 (Ulithi, Guam).

Demiegretta jugularis Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Truk, Ponapé, Pelew).

Demiegretta jugularis grayi Uchida, Annot. Zool. Japon., 9, 1918, pp. 484, 488, 490 (Ponapé).

Demiegretta sacra sacra Kuroda, in Momiyama, Birds Micronesia, 1922, p. 36 (Guam, Saipan, Angaur, Luganor, Yap, Ngoli, Ruk, Ponapé, Kusaie, Taluit).

Demigretta sacra sacra Wetmore, in Townsend and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, p. 171 (Kusaie); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 198 (Carolines); Yamashina, Tori, 7, 1932, p. 406 (Ponapé); Hand-list Japanese Birds, rev., 1932, p. 183 (Saipan, Guam, Babelthuap, Peliliu, Angaur, Ngulu, Yap, Truk, Lukunor, Ponapé, Kusaie, Jaluit, Majuro); Mayr and Amadon, Amer. Mus. Novit., no. 1144, 1941, p. 10 (Guam, Saipan, Palau, Ponapé, Kusaie, Ruk, Tah); Hand-list Japanese Birds, 3d ed., 1942, p. 203 (Saipan, Rota, Babelthuap, Peliliu, Angaur, Ngulu, Yap, Ulithi, Truk, Lukunor, Ponapé, Kusaie, Jaluit, Arhno, Majuro, Moloclab, Wotze, Likieb, Ailuk); Mayr, Birds Southwest Pacific, 1945, pp. 51, 284 (Micronesia); Downs, Trans. Kansas Acad. Sci., 49, 1946, p. 90 (Tinian); Strophlet, Auk, 63, 1946, p. 535 (Guam); Borror, Auk, 64, 1947, p. 417 (Agrihan); Stott, Auk, 64, 1947, p. 524 (Saipan); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 42 (Rota, Guam, Peleliu, Ulithi, Truk).

Demigretta sacra micronesiae Momiyama, Tori, 5, no. 22, 1926, p. 110 (Type locality, Caroline Islands; Pelew, Yap, Truk, Ponapé, Kusaie).

Geographic range.—Coasts of Asia and adjacent islands from Korea and Japan south to Malaysia, Australia, Melanesia, Polynesia and Micronesia. In Micronesia: Mariana Islands—Agrigan, Tinian, Saipan, Rota, Guam; Palau Islands—Babelthuap, Koror, Garakayo, Ngesebus, Peleliu, Ngabad, Anguar; Caroline Islands—Ulithi, Yap, Ngulu, Truk, Lukunor, Ponapé, Kusaie; Marshall Islands—Jaluit, Arhno, Majuro, Maloclab, Wotze, Likieb, Ailuk, Bikini, Eniwetok, Kwajalein.

Characters.—A medium-sized heron with three color phases: in gray phase color of body varies from "deep blackish-slate" to light bluish-slate, particularly on the breast, with a white gular stripe; wear and fading causes the color of the body to change to brownish-slate; bluish-gray ornamental plumes may be present on adult; in white phase color of body is pure white in adult stage; plumage of immature may be mottled; in mottled phase there may be a variable amount of gray and white (for complete study of plumages of Demigretta sacra see Mayr and Amadon, 1941:4).

Measurements.—Mayr and Amadon (1941:1) record the length of the wing of thirty adults from the Marianas and Carolines as 268-309 (284). Seven adult males obtained by the NAMRU2 party at Rota, Guam and Peleliu measure: wing, 287-307 (294); tail, 95-114 (101); culmen, 91-101 (96); tarsus, 78-87 (82); seven adult females, from Rota and Guam: wing, 265-285 (275); tail, 87-96 (91); culmen, 86-92 (89); tarsus, 72-79 (76).

Weights.—The author (1948:42) lists the following weights: four adult males from Guam (gray phase) 590-667 (614); two adult males from Guam (white phase) 600 and 662; five adult females from Guam and Rota (gray phase) 477-553 (506).

Specimens examined.—Total number, 80 (38 males, 40 females, 2 unsexed) as follows: Mariana Islands, USNM—Rota, 3 (Oct. 18, Nov. 2, 5)—Guam, 21 (May 11, June 6, 18, July 6, 8, 16, 24, 27, Aug. 6, 8, 27); AMNH—Saipan, 2 (July 22)—Guam, 9 (Feb. 11, Mar. 6, 7, April 11, Aug. 15, Sept. 14, 16, Nov. 27, Dec. 20); Palau Islands, USNM—Peleliu, 3 (Sept. 10, 16); AMNH—exact locality not given, 5 (Nov. 8, 21, 23); Caroline Islands, USNM—Ulithi, 1 (Aug. 15)—Kusaie, 1 (Feb. 8); AMNH—Truk, 3 (Feb. 18, May 20, Nov. 5)—Tah, 2 (Oct. 18)—Ponapé, 2 (Nov. 21, undated)—Kusaie, 26 (Jan. 25, 26, Feb., Mar. 10-20, 20-30, April 1-10, 18); Marshall Islands, USNM—Bikini, 2 (March 29, April 2).

Nesting.—The Reef Heron apparently nests on most of the islands in Micronesia. The eggs are laid in a nest of grass and twigs on or near the ground. Hartert (1898:64) records a nest found in grass at Saipan on July 28, 1895. Yamashina (1932a:406) reports on one egg taken at Ponapé on July 23, 1931. Marshall (1949:219, fig. 37) found a breeding bird in April at Tinian. Coultas (field notes) learned from the natives at Ponapé that the Reef Heron builds a nest of small sticks near the ground in the mangrove thickets. Two or three eggs are laid, and nests can be found at various times of the year. Mayr and Amadon (1941:4) comment on the prolonged breeding season and report six sets of eggs from Polynesia taken in January, March, April, September, October, and November.

Food habits.—The author (1948:42) found fish and crabs in the stomachs of birds taken at Guam, Ulithi and Peleliu.

Parasites.—Uchida (1918:484, 488, 490) found the following bird lice (Mallophaga) on the Reef Heron at Ponapé: Nirmus orarius, Colpocephalum importunum, and Myrsidea teraokai. Bequaert (1939:81 and 1941:266) found the fly (Hippoboscidae), Ornithoctona plicata, on the heron at Kusaie. Wharton (1946:175) and Wharton and Hardcastle (1946:306, 316) obtained chiggers (Acarina), Neoschöngastia egretta and N. carveri, from the Reef Heron at Guam and Ulithi.

Remarks.—The species Demigretta sacra contains two subspecies, the widespread D. s. sacra and a larger form, D. s. albolineata (Gray), known from New Caledonia and the Loyalty Islands. The latter subspecies is surrounded by the former, a distribution which closely parallels that in each of the species Phalacrocorax melanoleucus and Gygis alba of Oceania. Recently Delacour (in Delacour and Mayr, 1945b:105) has dropped the name Demigretta placing all of the forms of this genus in Egretta. He says, "We cannot accept the genus Demigretta, which is based on the more extended feathering of the tibia, the different length and texture of the feathers of the trains, the shortness of the tarsus and the presence of a dark gray color phase. The latter exists in the Madagascan and African subspecies of Egretta garzetta."

The Reef Heron is a conspicuous member of the bird life of Micronesia, being recorded from most of the island groups. It prefers the placid and shallow waters of the lagoons and tidal beaches where it obtains the littoral animal life as food. The birds are seldom seen inland and usually frequent the beaches and rocky coasts. In this respect there is little opportunity for competition with the migratory Plumed Egret, which prefers the grassy upland and marsh areas and inland ponds. The Reef Heron is a quiet, usually solitary, and retiring bird, being exceedingly difficult to approach, especially when found on the open tidal flats.

The problem of plumages and color phases in the Reef Heron has been treated by Mayr and Amadon (1941:4-10). Specimens which they examined from Micronesia were found to be 54 percent gray, 40 percent white, and 6 percent mottled. Of the birds obtained by NAMRU2 field parties, fewer than 40 percent were white. Field counts showed a considerable variation in the ratio of grays to whites: Guam—6 grays to 4 whites; Ulithi—4 grays, 6 whites, 1 mottled; Palau—equal number of grays and whites; Truk—2 whites, 1 gray, 1 mottled. For some unknown reason, the gray birds were more easily approached than the white birds. Gleise and Genelly (1945:221) saw one white Reef Heron at Eniwetok. Wallace (field notes) found white herons more numerous than gray ones at Kwajalein in 1944 and 1945. Borror (1947:417) observed gray birds at Agrigan. Stott (1947:524) saw one blue heron on December 24, at Saipan. The 150 birds seen by him at Lake Susupe in December probably were Plumed Egrets.

In discussing the variation in the color phases of the Reef Heron throughout its range, Mayr (1924b:237) suggests that the reduced variability of small populations may not be due to accidental gene loss, but instead to the population having descended from a single pair or from one fertilized female. The descendents would naturally possess only those characters provided for in the genetic make-up of the parents. Reef Herons on New Zealand and in the Marquesas Islands all are gray, while at other island groups different proportions of gray and white individuals occur; such phenomena may result because of the genetic constitution of the "founders."

Nycticorax nycticorax nycticorax (Linnaeus)

Black-crowned Night Heron

Ardes Nycticorax Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 142. (Type locality, Southern Europe.)

Nycticorax griseus Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 105 (Uap); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 123 (Yap); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 69 (Uap).

Nycticorax nycticorax Sharpe, Cat. Birds British Mus., 26, 1898, p. 146 (Yap).

Nycticorax nycticorax nycticorax Kuroda, in Momiyama, Birds Micronesia, 1922, p. 36 (Mackenzie, Yap); Hand-list Japanese Birds, rev., 1932, p. 183 (Yap, Uluthi); Hand-list Japanese Birds, 3d ed., 1942, p. 204 (Yap, Uluthi); Mayr, Birds Southwest Pacific, 1945, p. 302 (Marianas, Yap).

Geographic range.—Europe and Africa east to Japan and Malaysia. In Micronesia: Mariana Islands—Tinian; Palau Islands—Koror; Caroline Islands—Yap, Ulithi, Truk.

Specimens examined.—Total number, 2 immature females, as follows: Palau Islands, USNM—Koror, 1 (Nov. 27); Caroline Islands, AMNH—Truk, 1 (June 18).

Remarks.—The Black-crowned Night Heron is a winter visitor to western Micronesia. Marshall (1949:221) records six of these birds on Tinian on April 4, 1945, and one on Koror on November 27.

Nycticorax caledonicus pelewensis Mathews

Rufous Night Heron

Nycticorax caledonicus pelewensis Mathews, Bull. British Ornith. Club, 46, 1926, p. 60. (Type locality, Pelew Islands.)

Nycticorax caledonicus Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 117, 118 (Pelew); Sharpe, Cat. Birds British Mus., 26, 1898, p. 158 (Pelew); Hartert, Novit. Zool., 7, 1900, p. 10 (Ruk); Reichenow, Die Vögel, 1, 1913, p. 255 (Palauinseln); Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Pelew); Uchida, Annot. Zool. Japon., 9, 1918, p. 486 (Palau); Wetmore, in Towsend and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, p. 172 (Uala, Truk Atoll); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 37 (Pelew, Ruk).

Nycticorax manillensis Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 105 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 33 (Palau); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 353 (Ruk); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 69 (Pelew, Ruk).

Nycticorax caledonicus pelewensis Mathews, Syst. Avium Australasianarum, 1, 1927, p. 200 (Pelew, Carolines); Peters, Proc. Boston Soc. Nat. Hist., 39, 1930, p. 271 (Pelew, Carolines); Peters, Check-list Birds World, 1, 1931, p. 115 (Pelew); Hand-list Japanese Birds, rev., 1932, p. 183 (Palau, Truk); Hand-list Japanese Birds, 3d ed., 1942, p. 204 (Babelthuap, Koror, Coracel, Truk); Amadon, Amer. Mus. Novit., no. 1175, 1942, p. 6 (Palau, Ruk); Mayr, Birds Southwest Pacific, 1945, p. 285 (Palau, Truk); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 43 (Angaur, Peleliu, Garakayo, Truk).

Geographic range.—Micronesia: Palau Islands—Babelthuap, Koror, Coracel, Garakayo, Peleliu, Ngabad, Angaur; Caroline Islands—Truk.

Characters.—Adult: Size medium; head and nape dark slaty-black; occipital plumes white with dark tips and shafts; back dark reddish-brown, lighter on sides of neck, wings, wing coverts, rump, and tail; under parts whitish with light reddish-brown on sides of neck extending to throat and upper breast; tibia with some brownish feathers; underwing pinkish; feet yellowish-brown; bill black.

Immature: Resembles adult, but upper parts mottled black with reddish-brown; underparts with lighter streaks of brown and whitish on breast; feet yellowish; bill black above, yellowish below.

Adult resembles N. c. manillensis Vigors, but is duller above.

Measurements.—Two adult males from Peleliu measure: wing, 293, 299; tail, 105, 107; culmen, 82, 89; tarsus, 79, 81; seven adult females from Peleliu: wing, 269-286 (280); tail, 101-106 (104); culmen, 76-84 (80); tarsus, 78-83 (80); one adult female from Truk: wing, 280; tail, 97; culmen, 83; tarsus, 79.

Specimens examined.—Total number, 27 (5 males, 18 females, 4 unsexed), as follows: Palau Islands, USNM—Peleliu, 9 (Aug. 31, Sept. 1, 5, 6, 8, Dec. 6); AMNH—exact locality not given, 16 (Nov. 7, 8, 13, 23, 25, Dec. 1, undated); Caroline Islands, USNM—Truk, 1 (Feb. 16); AMNH—Truk, 1 (May 25).

Nesting.—The NAMRU2 party observed a nesting colony of these night herons at Peleliu on August 29, 1945. Approximately eight nests were observed in a grove of saplinglike trees at the edge of a mangrove swamp. These nests were 15 to 20 feet above the ground; most of them contained one or two nestling birds. Two subadults and three nestlings in postnatal molt were obtained; no eggs were found. Marshall (1948:219) records breeding in August, September and December.

Food habits.—Baker (1948:43) reports that stomachs of night herons obtained by the NAMRU2 party at Peleliu contained a great variety of animal foods, including eels, fish, lizards (skinks), crabs, shrimp, and insects. The stomach of one adult contained 14 large grasshoppers and four fish, totaling about 15 cc. in volume. The nestlings had eels, skinks, and insects in their stomachs.

Parasites.—Uchida (1918:486) found the bird louse (Mallophaga), Lipeurus baculus, on the night heron at Palau.

Remarks.—Amadon (1942:4-8) has made the most recent study of the species Nycticorax caledonicus and recognizes eight subspecies from Australia and New Calendonia north to the Caroline and Bonin islands. This is one of the few tropical and subtropical species which has extended its range to the Bonin islands. The discontinuous distributions of this species prevents an accurate estimation of the route by which it reached the Bonins. The presence of the bird at Palau and at Truk makes it difficult to account for its absence at Yap and other intervening, and seemingly suitable, islands. Populations at Palau and Truk appear to be similar and are placed in the same subspecies, but when adequate material is available from Truk, further study may reveal that the populations on the two islands (Truk and Palau) are recognizably different.

At the southern Palau Islands, night herons were found by the NAMRU2 party in mangrove swamps, lagoons and on beaches. I found them to be inactive during the daytime; the birds were usually perched singly in trees or at the edge of the water. The birds appeared to have special roosting places and were observed sitting in the same place on several different occasions. McElroy of the NAMRU2 party reported seeing three night herons at Truk in December, 1945.

Gorsachius goisagi (Temminck)

Japanese Bittern

Nycticorax goisagi Temminck, Pl. Col., livr. 98, 1835, pl. 582. (Type locality, Japan.)

Gorsakius goisagi Hand-list Japanese Birds, rev., 1932, p. 184 (Koror); Hand-list Japanese Birds, 3d ed., 1942, p. 204 (Koror); Mayr, Birds Southwest Pacific, 1945, p. 302 (Palau).

Geographic range.—Eastern China, Japan, Riu Kius, Formosa, and Philippine Islands. In Micronesia: Palau Islands—Koror.

Remarks.—Gorsachius goisagi has been recorded from Koror in the Palau Islands. It may be classed as a rare migrant to western Micronesia.

Gorsachius melanolophus melanolophus (Raffles)

Malay Bittern

Ardea melanolopha Raffles, Trans. Linn. Soc. London, 13, 1822, p. 326. (Type locality, Western Sumatra.)

Nycticorax goisagi Hartlaub and Finsch, Proc. Zool. London, 1868, pp. 8, 118 (Pelew); idem, Proc. Zool. Soc. London, 1872, p. 89 (Pelew); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 68 (Pelew).

Nycticorax melanolophus Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 35 (Palau).

Gorsachius melanolophus Sharpe, Cat. Birds Brit. Mus., 26, 1898, p. 166 (Pelew).

Gorsahius melanolophus melanolophus Hand-list Japanese Birds, rev., 1932, p. 184 (Pelew); Hand-list Japanese Birds, 3d ed., 1942, p. 204 (Palau); Mayr, Birds Southwest Pacific, 1945, p. 302 (Palau).

Gorsachius melanolophus melanolophus Mathews, Syst. Avium Australasianarum, 1, 1927, p. 200 (Pelew).

Geographic range.—India, Ceylon, southern China, Formosa, Indochina, Malaysia. In Micronesia: Palau Islands—exact locality unknown.

Remarks.—Captain Tetens obtained a specimen of this bittern at the Palau Islands which was reported on by Hartlaub and Finsch (1868a:8, 1868b:118). It is probably a rare straggler to western Micronesia. The specimen has not been seen by me; it may be of the subspecies G. m. kutteri (Cabanis), which is known from the Philippine Islands.

Ixobrychus sinensis (Gmelin)

Chinese Least Bittern

Ardea Sinensis Gmelin, Syst. Nat., 1, pt. 2, 1789, p. 642. (Type locality, China.)

Ardea lepida Lesson, Traité d'Ornith., 1831, p. 573 (Marianne); Hartlaub, Journ. f. Ornith., 1854, p. 167 (Mariannen).

Ardea sinensis Kittlitz, Obser. Zool., in Lutké, Voy. "Le Séniavine," 3, 1836, p. 305 (Guahan); Gray, Hand-list Birds, 3, 1871, p. 31 (Marian); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 105 (Uap); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 123 (Yap); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 33 (Palau, Yap); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 353 (Ruk).

Ardea (Ardetta) sinensis Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 49 (Ladrone or Marian Islands).

Ardetta Sinensis Salvadori, Ornith. Papuasia, 3, 1882, p. 364 (Pelew, Carolines, Mariannis); Oustalet, Le Nat., 1889, p. 261 (Mariannes); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 68 (Marianne, Uap, Ruk, Pelew); Oustalet, Nouv. Arch, Mus. Hist. Nat. Paris, (3), 8, 1896, pp. 38, 39 (Guam, Saypan, Ponapi, Ruk, Palaos); Hartert, Novit. Zool., 5, 1898, p. 65 (Guam); Sharpe, Cat. Birds British Mus., 26, 1898, p. 227 (Marianne, Carolines, Pelew); Hartert, Novit. Zool., 7, 1900, p. 11 (Ruk); Safford, Contr. U. S. Nat. Herb., 9, 1905, p. 79 (Guam); Prowazek, Die deutschen Marianan, 1913, p. 100 (Saipan); Cox, Island of Guam, 1917, p. 21 (Guam).

Ardetta bryani Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 27 (Type locality, Guam); Safford, Osprey, 1902, p. 66 (Guam); idem, The Plant World, p. 266 (Guam).

Ardetta sinensis sinensis Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Ruk, Pelew).

Ixobrychus sinensis bryani Wetmore, in Townsend and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, pp. 173, 175 (Guam); Kuroda, in Momoyama, Birds Micronesia, 1922, p. 37 (Guam,?Yap,?Mackenzie,?Pelew); idem, Avifauna Riu Kiu, 1925, p. 134 (Guam,?Yap,?Pelew); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 202 (Guam,?Pelew); Peters, Check-list Birds World, 1, 1931, p. 121 (Guam); Hand-list Japanese Birds, rev., 1932, p. 184 (Saipan, Tinian, Rota, Guam); Oberholser, Bull. U. S. Nat. Mus., 159, 1932, p. 18 (Guam); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Hand-list Japanese Birds, 3d ed., 1942, p. 205 (Saipan, Tinian, Rota, Guam); Amadon, Bull. Bernice P. Bishop Mus., 186, 1945, p. 25 (Guam); Stott, Auk, 64, 1947, p. 525 (Saipan); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 44 (Rota, Guam).

Ixobrychus sinensis moorei Wetmore, in Townsend and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, p. 173 (Type locality, Uala, Truk group); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 38 (Ruk); Kuroda, Avifauna Riu Kiu, 1925, p. 134 (Ruk); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 202 (Middle Carolines); Peters, Check-list Birds World, 1, 1931, p. 121 (Truk); Hand-list Japanese Birds, rev., 1932, p. 184 (Palaus, Yap, Truk); Oberholser, Bull. U. S. Nat. Mus., 159, 1932, p. 17 (Carolines, ?Pelews); Hand-list Japanese Birds, 3d ed., 1942, p. 205 (Babelthuap, Koror, Yap, Truk); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 44 (Truk, Peleliu).

Ixobrychus sinensis Hartert, Vogel pal. Fauna, 10, 1920, p. 1260 (Truk, Palau, Guam); Mayr, Birds Southwest Pacific, 1945, p. 285 (Marianas, Palau, Yap, Truk); Watson, The Raven, 17, 1946, p. 41 (Guam); Downs, Trans. Kansas Acad. Sci., 49, 1946, p. 91 (Tinian); Wharton, Ecol. Monogr., 16, 1946, p. 174 (Guam); Delacour and Mayr, Birds Philippines, 1946, p. 29 (Guam); Strophlet, Auk, 63, 1946, p. 536, (Guam); Baker, Condor, 49, 1947, p. 125 (Guam).

Ixobrychus sinensis sinensis Hachisuka, Birds Philippines, 1, 1932, p. 365 (Guam, Truk); Robinson and Chasen, Birds Malay Peninsula, 3, 1936, p. 195 (Marianne).

Ixobrychus sinensis palewensis Momiyama, Bull. Biogeogr. Soc. Japan, 2, 1932, p. 333 (Type locality, Pelew); Mathews, Ibis, 1933, p. 88 (Pelew).

Ixobrychus sinensis yapensis Momiyama, Bull. Biogeogr. Soc. Japan, 2, 1932, p. 333 (Type locality, Yap); Mathews, Ibis, 1933, p. 89 (Yap).

Geographic range.—Northeastern China and Japan south to Micronesia, Malaysia, Burma, India and Ceylon. Winter visitor to Papuan region. In Micronesia: Mariana Islands—Saipan, Tinian, Rota, Guam; Palau Islands—Babelthuap, Koror, Peleliu; Caroline Islands—Yap, Truk.

Characters.—Adult male: A small bittern with crown and short occipital crest slaty-black; mantle light buffy-brown; back and rump gray; tail black; wing-coverts brownish-buff; primaries and secondaries slaty-black; underparts yellowish buff; chin and throat whitish; sides of head and neck and a line of feathers across chest blackish edged with buff; bill yellowish green; feet greenish yellow.

Adult female: Resembles adult male, but with upper parts mottled brown and golden chestnut; underparts deep buff streaked with pale brown on neck.

Immature: Resembles adult, with upper parts heavily streaked with blackish-brown, and underparts streaked with chestnut and dark brown.

Measurements.—Measurements of specimens from Micronesia are given in [table 16].

Table 16. Measurements of Ixobrychus sinensis From Micronesia

Table 16. Measurements of Ixobrychus sinensis From Micronesia

Weights.—The author (1948: 44) records the weights of eight adult males from Guam as 82-103 (92) and eight adult females from Guam as 84-109 (95).

Specimens examined.—Total number, 69 (34 males, 27 females, 8 unsexed), as follows: Mariana Islands, USNM—Saipan, 1 (Sept. 30)—Tinian, 1 (Oct. 13)—Guam, 29 (May 16, June 4, 6, 7, 8, 14, 18, 19, July 10, 16, 18, 24, 27, Aug. 4); AMNH—Saipan, 1 (Aug. 6)—Tinian, 3 (Sept. 13)—Guam, 14 (Feb. 1, Mar. 13, 29, July 11, 13, 25, Aug. 1, 7, 13, Sept. 4, 10, Dec. 8); Palau Islands, AMNH—exact locality not given, 6 (Nov. 19, 21, 23, 25, Dec. 1, 18); Caroline Islands, USNM—Truk, 1 (Feb. 16); AMNH—Yap, 1 (not dated)—Truk, 12 (Feb. 9, Mar. 5, 17, May 7, June 13, 14, 15, Oct. 3, Nov. 1, 5, Dec. 20).

Nesting.—The author (1948:44) records a nest found by the NAMRU2 party near Achang Bay on Guam on June 6, 1945. It was found in a cane thicket at the edge of a fallow rice paddy, approximately four feet from the ground and was constructed of about three quarts of reeds and cane. Two eggs found in the nest are oval, white with a greenish cast and measure 33 by 24 and 34 by 24. On February 1, 1945, the writer found two recently occupied nests of the Chinese Least Bittern at Oca Point, Guam. These nests were in dense inkberry brush approximately five feet above the ground. The area was not marshy, the nearest water being at the beach some 300 yards away. Nearby one of the nests was found a young bittern, which apparently had only recently left the nest. The pin feathers were growing. A parent bird remained in the vicinity with the young bird until it left the area after March 9.

Food habits.—The Chinese Least Bittern feeds on animal foods obtained along waterways, marshes and beaches as well as in forests and fields. The NAMRU2 party observed several types of insects in the stomachs of birds taken at Guam. Seale (1901:27) found black crickets in stomachs of bitterns taken at Guam. Coultas (field notes) learned from the natives of the Palau Islands that the bittern feeds on land mollusks.

Parasites.—Wharton (1946:174) obtained the chigger (Acarina), Trombicula acuscutellaris, from the Chinese Least Bittern at Guam.

Remarks.—The Chinese Least Bittern has been regarded by many workers as consisting of several geographic races; as many as eight have been recognized. Other workers have concluded that I. sinensis is made up of highly variable populations and that it lacks well-fined geographic variation. Hartert (1920:1260), Hachisuka (1932:365), and Mayr (1945a:285) have reached the latter conclusion. As yet this problem has not been satisfactorily solved; a thorough study is needed, but may not be possible until additional material, especially from the continental areas, can be obtained. In coloration there appears to be little difference between birds from the various localities in Micronesia. These birds may average slightly paler than populations from the continental areas, but on this basis I doubt that a person could recognize the Micronesian birds in a group of skins from many other localities. Birds in fresh plumage may show geographic differences better than slightly worn specimens. Measurements made by the author offer no clear-cut differences either.

I. sinensis was first recorded in Micronesia by Quoy and Gaimard (1824:536), whose ship, the "Uranie," stopped at Guam. They called the bird "Petit Héron aux ailes noires." Most of the ornithological collectors in the years following Quoy and Gaimard obtained this bittern in Micronesia. At Guam, its abundance and the ease with which it may be approached and shot is attested by the large series obtained by collectors: Seale (1901:27) took eight birds; Marche (Oustalet, 1896:36) took eighteen skins; the NAMRU2 party took twenty-nine skins.

The Chinese Least Bittern is found in habitats associated with both salt water and fresh water, as well as in upland habitat in Micronesia. The bird appears to be well adapted to areas of open forest and coconut groves. Coultas (field notes) found the birds in taro patches in the Palaus. Although a considerable amount of field observing was done in the southern Palaus, the NAMRU2 party saw only one bird (September 13, 1945, at Peleliu). Perhaps the birds prefer Babelthuap and other large islands farther north in the chain. McElroy found bitterns in taro patches at Truk in December, 1945. The NAMRU2 party did not find any birds at Rota in October and November, 1945. Downs (1946:91) found the birds in upland sugar cane and beach habitats on Tinian.

Regarding the bittern in the Palaus, Coultas (field notes) writes, "Always found alone, never a pair. A bird that is not easily frightened. In the heat of the day, one finds it standing in the shade of a taro leaf quietly viewing the intruder and very reluctant about moving. I have tossed pieces of earth and sticks at the bird to encourage him to fly so that I would not blow him to pieces when I shot, but my efforts at dislodgement have been rewarded by harsh scolding squawks. It became necessary for me to move into proper gun range. I have also found them perched in low trees at the edge of taro swamps. In flight they are atrociously awkward. They can't keep a course and their legs dangle every-which way. Their jerky, slow flight usually ends abruptly when the bird becomes entangled in weeds or the branches of trees. Extracting himself from his predicament he is soon in another and invariably resorts to blasphemy."

Ixobrychus eurhythmus (Swinhoe)

Schrenck's Least Bittern

Ardetta eurhythma Swinhoe, Ibis, 1873, p. 74, pl. 2. (Type locality, Amoy Shanghai.)

Ixobrychus eurythmus Mayr, Birds Southwest Pacific, 1945, p. 302 (Palau).

Geographic range.—Southeastern Siberia and Japan south to India and Malaysia. In Micronesia: Palau Islands—exact locality unknown.

Specimens examined.—Total number, 3 (2 males, 1 female), from Palau Islands, AMNH—exact locality not given (Nov. 19, 21, Dec. 3).

Remarks.—Coultas obtained three immature specimens at Palau in November and December, 1931.

Dupetor flavicollis flavicollis (Latham)

Black Bittern

Ardea flavicollis Latham, Ind. Ornith., 2, 1790, p. 701. (Type locality, India.)

Dupetor flavicollis Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 26 (Guam); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam).

Dupetor f. flavicollis Mayr, Birds Southwest Pacific, 1945, p. 302 (Guam).

Geographic range.—Central China south to Malaysia and India. In Micronesia: Mariana Islands—Guam.

Remarks.—Seale (1901:26) records a female shot at the Agaña River on Guam on June 11, 1900. The skin probably is in the Bernice P. Bishop Museum in Honolulu.

Anas oustaleti Salvadori

Marianas Mallard

Anas oustaleti Salvadori, Bull. British Ornith. Club, 4, 1894, p. 1. (Type locality, Mariannis Islands.)

Anas oustaleti Salvadori, Cat. Birds British Mus., 27, 1895, p. 189 (Guaham); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 49 (Guam); Hartert, Novit. Zool., 5, 1898, p. 66 (Guam, Saipan); Wheeler, Report Island of Guam, 1900, p. 13 (Guam); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 25 (Guam, Saipan); Matschie, Journ. f. Ornith., 1901, pp. 110, 113 (Guam, Saipan); Safford, Osprey, 1902, p. 66 (Mariannas); idem, Amer. Anthro., 4, 1902, p. 711 (Guam); idem, The Plant World, 7, 1904, p. 267 (Guam); Dubois, Syn. Avium, 2, 1904, p. 990 (Mariannes); Safford, Contr. U. S. Nat. Herb., 9, 1905, pp. 80, 126 (Guam); Prowazek, Die deutschen Marianen, 1913, pp. 47, 100 (Marianen); Cox, Island of Guam, 1917, p. 22 (Guam); Phillips, Nat. Hist. Ducks, 2, 1923, p. 53 (Guam, Saipan); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 214 (Guam, Saipan); Berlioz, Bull. Mus. Hist. Nat. Paris, 2d ser., 1, 1929, p. 67 (Guam); Peters, Check-list Birds World, 1, 1931, p. 159 (Guam, Tinian, Saipan); Hand-list Japanese Birds, rev., 1932, p. 184 (Guam, Tinian, Saipan); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Kuroda, Tori, 11, 1941-42, pp. 99, 443 (Marianas); Hand-list Japanese Birds, 3d ed., 1942, p. 205 (Guam, Tinian, Saipan); Amadon, Amer. Mus. Novit., no. 1237, 1943, p. 1 (Marianne); Mayr, Birds Southwest Pacific, 1945, p. 285 (Marianas); idem, Audubon Mag., 47, 1945, p. 282 (Marianas); Baker, Trans. 11th N. Amer. Wildlife Conf., 1946, p. 208 (Guam); Stott, Auk. 64, 1947, p. 525 (Saipan); Baker, Smithson, Misc. Coll., vol. 107, no. 15, 1948, p. 45 (Saipan, Tinian); Momiyama, Pacific Science, 2, 1948, p. 121 (Saipan, Tinian, Guam).

Polionetta oustaleti Kuroda, in Momiyama, Birds Micronesia, 1922, p. 39 (Guam, Saipan).

Anas superciliosa oustaleti Hartert, Novit. Zool., 36, 1930, p. 112 (Guam, Saipan).

Anas platyrhynchos oustaleti Delacour and Mayr, Wilson Bull., 57, 1945, pp. 21, 39 (Marianas).

Geographic range.—Micronesia: Mariana Islands—Guam, Tinian, Saipan.

Characters.—From study of a large series of specimens of Anas oustaleti, Yamashina (1948) described two types of plumages: one type resembles that of A. platyrhynchos and another type resembles that of A. poecilorhyncha. He based his conclusions on both a study of prepared skins and observations of the molt of living specimens as reported by Kuroda (1941-1942). The following descriptions are quoted from Yamashina (1948:122).

Adult male in nuptial plumage of A. platyrhynchos type: "Whole head is dark green, except at the sides where buff feathers are plentifully intermingled, a dark brown streak through the eye, and faint white ring on the lower neck. Feathers on scapulars and sides of body are as those of Anas poecilorhyncha. Sides of body are vermiculated but some brown feathers are found even in the full nuptial plumage. Upper breast is dark reddish chestnut with dusky spots. Upper and under tail-coverts are as in Anas platyrhynchos. Speculum is as that of Anas platyrhynchos, but the tips of the greater coverts are buff instead of white. Central tail feathers are more or less curled upward. Base of bill is black, tip is olive color. Iris is dark brown. Feet, reddish-orange, webs darker." Eclipse plumage of adult male resembles that of A. platyrhynchos.

Adult male in nuptial plumage of A. poecilorhyncha type: "Resembles Anas poecilorhyncha pelewensis from the Palau Islands and Truk Island, but sides of head are browner, superciliary stripes and ground color of cheeks are more buffy. Feathers on upper breast and sides of body are more broadly edged with brown. Speculum is usually violet-purple as in the platyrhynchos type, but in two specimens from Saipan and Tinian, respectively, it is dark green as in Anas poecilorhyncha pelewensis. Tips of the secondaries are usually white, but sometimes very faint as in Anas poecilorhyncha pelewensis, and in one specimen from Saipan they are buffy. Bill is olive color with a black spot in the center of the upper mandible. Iris, dark brown. Feet, dark orange, darker in joints and webs." Eclipse plumage of adult male resembles the nuptial plumage.

Measurements.—Measurements of nine ducks from Guam and Saipan are: wing, 238-266 (252); tail, 75-84 (81); exposed culmen, 49-53 (51); tarsus, 41-43 (42).

Specimens examined.—Total number, 9 (5 males, 2 females, 2 unsexed), as follows: Mariana Islands, USNM—Saipan, 2 (Oct. 2, 3)—Guam, 1 (June 6); AMNH—Saipan, 2 (Aug. 7, 11)—Guam, 4 (Jan. 10, April 6, Dec. 11, 16).

Nesting.—At Guam, Seale (1901:25) found nests of the Marianas Mallard "among the reedy swamps and streams of the island." He obtained two downy young in June. Kuroda (1941-1942) reports nesting at Lake Challankanoa, Saipan, in July. He writes that nests contained 7 to 12 eggs. Ducklings and incubated eggs were obtained in June and July, but he is of the opinion that the breeding season may be longer. He notes that adults exhibit both nuptial plumage and eclipse plumage at the same time, suggesting that breeding may occur at various times in the year. A nest with seven eggs taken on July 4, 1941, at Hagoi Lake, Tinian, is described by Kuroda as having been found among rushes and constructed of dead leaves, stems, and roots and lined with down. He describes the eggs as being grayish-white with a pale greenish tinge, and measuring 61.6 by 38.9. Marshall (1949:202) saw a family of ducklings in April.

Remarks.—The Marianas Mallard is rare; probably it never has been very abundant in the small chain of islands to which it is restricted, because fresh water marshes and swamps are not extensive. The bird was first recorded by Bonaparte as Anas boschas a. Freycineti in 1865. This name was a nomen nudum and later the same specimen in the Paris Museum was named by Salvadori (1894) as Anas oustaleti. In 1888, Marche obtained six specimens at Guam; these were reported on by Oustalet (1896:49). Later collecting showed that the duck inhabited also the islands of Saipan and Tinian. There have been no records of this duck in the more northern islands of the Marianas. According to Yamashina (1948:121) in the period from 1931 to 1940, the Japanese obtained 38 specimens of the Marianas Mallard at Tinian and Saipan. In 1940, four birds from Tinian were shipped alive to Japan and kept in an aviary by Kuroda. At Tinian in 1940, one of the collectors observed two flocks of A. oustaleti, each containing 50 or 60 individuals. The Japanese took specimens at a lagoon area and at fresh water lakes. Yamashina describes one of the localities, Lake Hagoi on Tinian, as "a small body of fresh water surrounded by about 40 acres of marsh." During the war, servicemen reported the presence of the Marianas Mallard at both Saipan and Tinian. Moran (1946:261) counted twelve ducks at Saipan. Stott (1947:525) saw seven birds at Lake Susupe on Saipan in December, 1945. He writes that the birds were gentle and easily approached and that they preferred winding channels in reed beds to open water. Marshall obtained two ducks at Lake Susupe in early October, 1945. These specimens are in the United States National Museum. He (1949:202) found ducks at both Saipan and Tinian; twelve was the greatest number seen at any one time. Gleise (1945:220) estimated that there were twelve birds on Tinian in 1945, remarking that their habitat was swamp area.

At Guam and Rota, the NAMRU2 party failed to obtain any specimens but received reports of the presence of ducks on both islands. At Guam, reports were obtained of ducks of unknown species at a fallow rice paddy in August, 1944, and in a marsh near Agat on June 13, 1945. The presence of Japanese soldiers in the interior of Guam made it inadvisable to investigate marshes and swamps of the interior and the upper courses of streams. H. G. Hornbostel, as quoted by Phillips (1923:54), reported that ducks were found at Guam only in the Tolofofo River Valley. The NAMRU2 field parties investigated the lower reaches of this valley and found no evidence of the ducks. The upper part of this valley was used as an artillery range in 1945. Probably the firing of field guns was a disturbing influence to any birds that might have been there. If the ducks were on Guam at that time, they must have been secretive and restricted in their movements. At Rota, two ducks which might have been A. oustaleti were seen by the NAMRU2 party on October 20, 1945, in a cultivated field.

These recent reports indicate that the Marianas Mallard is secure for the present on the islands of Saipan and Tinian, but thoughtful conservation practices need to be placed in operation to insure its survival in the future.

Evolutionary history of Anas oustaleti.—In the past, most of the studies have pointed to a northern ancestry for A. oustaleti. Bryan (1941:187) has noted a relationship between A. oustaleti and the Laysan Duck (A. laysanensis Rothschild) and the Hawaiian Duck (A. wyvilliana Sclater). Amadon (1943:1) suggests that these three species of ducks are rather recent derivatives of the Common Mallard (A. platyrhynchos) and postulates the evolution of A. wyvilliana from migrants from North America. He further states that A. laysanensis and A. oustaleti may have been derived from A. wyvilliana or may represent independent colonizations. Delacour and Mayr (1945:21) go a step further and make these forms subspecies of A. platyrhynchos, saying that they are "dull-colored editions" of the Common Mallard, that because of isolation they have become reduced in size and have lost many of the characteristics of their ancestors. Recently, however, Yamashina (1948) has concluded that the Marianas Mallard has evolved as the result of hybridization between the two species, A. platyrhynchos and A. poecilorhyncha. His conclusions are based on a study of a large number of specimens, both museum skins and captive birds, in which he has been able to detect plumages of the A. platyrhynchos type and of the A. poecilorhyncha type (see Characters). He has noted specimens which have ninety percent of the characteristics of A. platyrhynchos and ten percent of the A. poecilorhyncha type. These percentages are reversed in specimens favoring the A. poecilorhyncha type. In his series of skins he finds the A. poecilorhyncha type of plumage most frequently, in forty-four specimens out of fifty examined, while only six specimens have the A. platyrhynchos type of plumage. Yamashina cites also as evidence favoring his conclusion that hybridization has taken place the results obtained from the crossing of captive A. platyrhynchos and A. poecilorhyncha. It is his assumption that there has been a resident form of A. poecilorhyncha in the Marianas, apparently resembling closely that which occurs in the Palaus and at Truk (A. p. pelewensis), and that stragglers of A. platyrhynchos from the north occasionally reach the Marianas where hybridization between the two species occurs. Yamashina remarks (1948:123): "The opportunity for hybridization should occur more rarely in the south, and thus more frequent back-crossing of the hybrid with the indigenous Anas poecilorhyncha on Tinian and Guam explains the superabundance there of the poecilorhyncha type. As the hybridization should have taken place more frequently to the north in Saipan, the ratio of the occurrence of the platyrhynchos type is logically higher there." The Common Mallard (A. p. platyrhynchos) has not been recorded in Micronesia, but according to Yamashina (1948:123) "winters frequently just north of the Marianas in the Bonin and Volcano Islands."

This remarkable explanation for the development of the Marianas Mallard is not questioned by this author, who feels that hybridization may be found to be the cause for other unusual forms of life in island habitats whose ancestry has not been explained. As Yamashina comments, the special environments of islands together with small and restricted populations of animals are factors which could favor such development.

Anas poecilorhyncha pelewensis Hartlaub and Finsch

Australian Gray Duck

Anas superciliosa var. pelewensis Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, p. 108. (Type locality, Pelew Islands.)

Anas superciliosa Hartlaub and Finsch, Proc. Zool. London, 1868, pp. 8, 118 (Pelew); Sclater, Proc. Zool. Soc. London, 1869, p. 659 (Pelew); Gray, Hand-list Birds, 3, 1871, p. 82 (Pelew); Salvadori, Ornith. Papuasia, 3, 1882, p. 395 (Pelew); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 70 (Pelew); Salvadori, Cat. Birds British Mus., 27, 1895, p. 206 (Pelew); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 50 (Palaos).

Anas superciliosa pelewensis Dubois, Syn. Avium, 2, 1904, p. 990 (Pelew); Mathews, Birds Australia, 4, 1915, p. 90 (Pelew); Phillips, Nat. Hist. Ducks, 2, 1923, p. 113 (Pelew); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 215 (Pelew); Hartert, Novit. Zool., 36, 1930, p. 112 (Pelew); Peters, Check-list Birds World, 1, 1931, p. 160 (Pelew); Hand-list Japanese Birds, rev., 1932, p. 184 (Palaus, Truk); Hand-list Japanese Birds, 3d ed., 1942, p. 205 (Babelthuap, Peliliu); Amadon, Amer. Mus. Novit., no. 1237, 1943, p. 3 (Palau); Mayr, Birds Southwest Pacific, 1945, p. 286 (Palaus, Truk); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 45 (Peleliu, Truk).

Anas pelewensis Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 40 (Palau); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 407 (Palau); Bolau, Mitteil. Naturhist. Mus. Hamburg, 1898, p. 71 (Palau).

Polionetta superciliosa pelewensis Kuroda, in Momiyama, Birds Micronesia, 1922, p. 38 (Pelew).

Anas superciliosa rukensis Kuroda, "Gan to Kamo" (Geese and Ducks), 1939, page not numbered, description between pls. 52 and 53 (Type locality, Ruk); Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Truk).

Anas poecilorhyncha superciliosa Delacour and Mayr, Wilson Bull., 57, 1945, pp. 21, 39 (no locality given); Yamashina, Pacific Science, 2, 1948, p. 122 (Palau, Truk).

Geographic range.—Islands of Micronesia, Polynesia, and Melanesia. In Micronesia: Palau Islands—Babelthuap, Peleliu; Caroline Islands—Truk.

Characters.—Adult: A medium-sized duck with upper parts dark brown, feathers edged with buff; top of head blackish merging into gray on hind neck with narrow buff line below; eye-stripe broad and blackish; lower parts uniformly dark brown to gray brown, feathers edged with buff; face, chin and throat light buff with some dark streakings; under wing white; speculum green; bill plumbeous with nail black; legs yellow-brown to yellowish, webs dusky. A. p. pelewensis resembles A. p. rogersi Mathews, but is smaller with a wing length averaging as much as 20 mm. shorter.

Measurements.—As given by Amadon (1943:4) seven unsexed skins from the Palaus, studied by Finsch (1875:40), have wing lengths of 207, 212, 212, 214, 223, 235, 230. For an adult male taken by Coultas at Palau, the exposed culmen measures 45 and the tarsus 37.

Specimens examined.—Total number, 3 males from Palau Islands, AMNH—exact locality not given (Oct. 26, Nov. 25).

Remarks.—A. p. pelewensis is apparently rare in the Palau Islands. Coultas, who visited the Palaus in October to December, 1931, writes (field notes) that he received reports that the birds were present and nested in numbers on fresh water lakes. He took specimens in taro patches and comments that the ducks probably feed at night and have retiring habits during the day. At Peleliu in 1945, the NAMRU2 party received several reports of ducks but failed to find the birds. At Truk, in December, 1945, McElroy of the NAMRU2 party found ducks to be fairly numerous in rice paddies, marshes, and swamps. He observed that the birds roosted at Moen Island at night but that they apparently flew to outlying islands to spend the day. Richards observed ducks on Moen Island on August 28 and 29, 1947, and again in the period from January 19 to February 10, 1948. He saw several flocks of ducks including one containing "about a dozen ducks" at ponds along a roadway and at an airstrip. Kuroda named the population at Truk as distinct in 1939. I have not been able to examine his description and no specimens are available for study, but if the birds at Truk represent an independent colonization (different from that of the birds at Palau) they might exhibit recognizable variation. Amadon (1943:5) has already pointed out that the shortness of the wing of specimens in the Palaus may merit subspecific status for the population. Delacour and Mayr (1945:21) propose that the Palau Gray Duck is a subspecies of A. poecilorhyncha; this treatment is followed in the present work.

Evolutionary history.—A. p. pelewensis, as Amadon (1943:1) has stated, represents a population of mallards which became separated from the ancestral stock in the Australian or Malayan area and when once differentiated, invaded New Zealand and other parts of Polynesia, Melanesia, and southwestern Micronesia. Amadon points out that its range in the Pacific islands is more or less complimentary to that of A. oustaleti in the Marianas and the Philippine Mallard (A. poecilorhyncha luzonica Fraser), as well as to the Hawaiian forms (A. wyvilliana Sclater and A. laysanensis Rothschild). The range of A. p. pelewensis gives one the impression that its present distribution may be only a stage in a gradual spreading of the species, for it certainly has not yet occupied all habitats suitable for it in southern Micronesia nor elsewhere in Oceania. As in the case of A. oustaleti, A. p. pelewensis appears to prefer areas of fresh, and possibly brackish, water on the larger islands.

A. p. luzonica is a near relative of A. p. pelewensis but has rufous-brown instead of buffy-brown coloring on the chin, throat, sides of head, and superciliary region. The underparts of the Philippine Mallard are much less mottled. The specula are similar. Both of these forms were probably derived from a mallard of the A. p. poecilorhyncha type.

Anas querquedula Linnaeus

Garganey Teal

Anas Querquedula Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 126. (Type locality, Europe, restricted to Sweden.)

Anas querquedula Marshall, Condor, 51, 1949, p. 221 (Tinian).

Geographic range.—Breeds in Europe and Asia. Winters from northern Africa to New Guinea. In Micronesia: Mariana Islands—Tinian.

Remarks.—Marshall (1949:221) obtained one of a pair of these ducks which he observed "daily in April on Lake Hagoi" at Tinian.

Anas crecca crecca Linnaeus

European Teal

Anas Crecca Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 126. (Type locality, Europe, restricted to Sweden.)

Querquedula crecca crecca Hand-list Japanese Birds, rev., 1932, p. 185 (Pagan).

Anas crecca crecca Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Pagan).

Anas crecca Mayr, Birds Southwest Pacific, 1945, p. 302 (Micronesia).

Geographic range.—Breeds in Iceland, northern Europe, Asia, and Aleutians. Winters south to northern Africa, Asia and Philippines. In Micronesia: Mariana Islands—Pagan.

Remarks.—The European Teal has been recorded by the Japanese at Pagan in the northern Marianas. It appears to be an uncommon winter visitor to Micronesia.

Anas crecca carolinensis Gmelin

Green-winged Teal

Anas carolinensis Gmelin, Syst. Nat., 1, pt. 2, 1789, p. 533. (Type locality, Carolina to Hudson Bay.)

Anas carolinensis Reichenow, Ornith. Monatsber., 1901, p. 17 (Jaluit); Schnee, Ornith. Monatsber., 1901, p. 131 (Marshalls); idem, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln); Phillips, Nat. Hist. Ducks, 2, 1923, p. 235 (Marshall Islands).

Querquedula crecca carolinensis Hand-list Japanese Birds, rev., 1932, p. 185 (Marshall Islands).

Anas crecca carolinensis Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Marshall Islands).

Geographic range.—Breeds in northwestern and northcentral North America. Winters to West Indies, Central America and Mexico. In Micronesia: Marshall Islands—Jaluit.

Remarks.—Reichenow (1901:17) and Schnee (1901:131) record the Green-wing Teal in the Marshall Islands. It is the only record known for Micronesia. Bryan and Greenway (1944:104) record the teal as a migrant to the Hawaiian Islands.

Anas acuta acuta Linnaeus

Pintail

Anas acuta Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 126. (Type locality, Europe, restricted to Sweden.)

Dafila acuta acuta Hand-list Japanese Birds, rev., 1932, p. 185 (Pagan).

Anas acuta acuta Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Pagan).

Anas acuta Mayr, Birds Southwest Pacific, 1945, p. 302 (Micronesia).

Geographic range.—Breeds in Iceland, northern Europe and Asia. Winters south to northern Africa, Asia and Philippines. In Micronesia: Mariana Islands—Pagan, Guam; Palau Islands—exact locality unknown.

Remarks.—The Pintail has been recorded from Pagan and Guam in the northern Marianas and from the Palau Islands and is thought to be an uncommon visitor to Micronesia. At Guam, Flavin (field notes) recorded one female on October 27, 1945, and three females and two drakes on January 19, 1946. Marshall (1949:221) saw a flock of fifteen Pintails at Saipan on February 7, 1945.

Anas acuta tzitzihoa Vieillot

Pintail

Anas tzitzihoa Vieillot, Nouv. Dict. Hist. Nat., 5, 1816, p. 163. (Type locality, Mexico, ex Hernandez.)

Anas acuta americana Reichenow, Ornith. Monatsber., 1901, p. 17 (Jaluit); Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln).

Anas acuta Schnee, Ornith. Monatsber., 1901, p. 131 (Marshalls); Phillips, Nat. Hist. Ducks, 2, 1923, p. 316 (Jaluit).

Anas acuta tzitzihoa Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Marshall Islands).

Geographic range.—Breeds in northwestern and northcentral North America. Winters south to West Indies, Panamá, and west to Hawaiian Islands. In Micronesia: Marshall Islands—Jaluit.

Remarks.—Reichenow (1901:17) and Schnee (1901:131) reported that flocks of ducks belonging to this and other American species were observed in the Marshall Islands in October, 1899, and May, 1900. This species may winter in the Hawaiian Islands, according to Peters (1931:167). If so it is not surprising that occasional visitors reach eastern Micronesia.

Anas penelope Linnaeus

Widgeon

Anas penelope Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 126. (Type locality, Europe, restricted to Sweden.)

Anas penelope Finsch, Ibis, 1880, pp. 332, 333 (Taluit); Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln); Phillips, Nat. Hist. Ducks, 2, 1923, p. 175 (Taluit); Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Tinian, Yap, Jaluit); Mayr, Birds Southwest Pacific, 1945, p. 302 (Micronesia).

Mareca penelope Finsch, Mitth. Ornith. Ver. Wien, 1884, p. 56 (Jaluit); Wiglesworth, Abhandl. und Ber Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 71 (Taluit); Finsch, Deut. Ver. zum Schultze der Vogelwelt, 18, 1893, p. 458 (Marshalls); Kuroda, in Momoyama, Birds Micronesia, 1922, p. 38 (Taluit); Hand-list Japanese Birds, rev., 1932, p. 185 (Tinian, Yap, Jaluit).

Geographic range.—Breeds in Iceland, northern Europe and Asia. Winters south to Africa, southern Asia and Philippines; casual to eastern North America. In Micronesia: Mariana Islands—Tinian; Caroline Islands—Yap; Marshall Islands—Jaluit.

Remarks.—The Widgeon may be an occasional winter visitor to Micronesia. The record at Jaluit in the Marshall Islands may be questioned.

Anas clypeata Linnaeus

Shoveller

Anas clypeata Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 124. (Type locality, Coasts of Europe, restricted to southern Sweden.)

Spatula clypeata Hand-list Japanese Birds, rev., 1932, p. 185 (Pagan); Yamashina, Tori, 10, 1940, p. 676 (Pingelap); Hand-list Japanese Birds, 3d ed., 1942, p. 206 (Pagan, Pingelap).

Anas clypeata Mayr, Birds Southwest Pacific, 1945, p. 302 (Micronesia).

Geographic range.—Breeds in northern Europe, Asia, North America and adjacent islands. Winters to northern Africa, southern Asia, Philippines, Hawaiians, southern United States to Central America. In Micronesia: Mariana Islands—Pagan, Tinian; Caroline Islands—Ponapé, Pingelap.

Specimens examined.—One female from Mariana Islands, USNM—Tinian (Oct. 12).

Remarks.—The Shoveller is known from localities in the Marianas and in the Carolines. In the collections of the American Museum of Natural History there is a female taken by Rollo Beck at Kauehi, Tuamotu Archipelago, on March 6, 1923. A specimen examined from Tinian was taken there by Joe T. Marshall, Jr., at Lake Hogoya on October 12, 1945. Richards obtained two Shovellers (one immature male and one immature female) at Ponapé on December 21, 1947, and January 6, 1948, respectively. He found them in a pond in a bomb crater. This duck appears to be a casual winter visitor to Micronesia and other parts of Oceania.

Aythya fuligula (Linnaeus)

Tufted Duck

Anas fuligula Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 128. (Type locality, Europe, restricted to Sweden.)

Fuligula cristata Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); idem, Proc. Zool. Soc. London, 1872, p. 90 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 40 (Palau); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 71 (Pelew); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 50 (Mariannes, Palaos).

Fuligula fuligula Salvadori, Cat. Birds British Mus., 27, 1895, p. 363 (Pelew); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 26 (Micronesia); Safford, Osprey, 1902, p. 70 (Mariannes); idem, The Plant World, 7, 1904, p. 268 (Guam); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 38 (Mariane, Pelew, Yap); idem, Avifauna Riu Kiu, 1925, p. 143 (Pelew, Marianne).

Marila fuligula McGregor, Man. Philippine Birds, 1909, p. 199 (Marianne, Pelew).

Nyroca fuligula Phillips, Nat. Hist. Ducks, 3, 1925, p. 234 (Guam); Hand-list Japanese Birds, rev., 1932, p. 185 (Pagan, Saipan, Palau, Yap); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Mayr, Birds Southwest Pacific, 1945, p. 302 (Micronesia).

Aytha fuligula Hand-list Japanese Birds, 3d ed., 1942, p. 207 (Pagan, Saipan, Tinian, Guam, Yap, Palau).

Geographic range.—Breeds in Iceland, Europe, northern Asia. Winters in Europe, Africa, Asia, Malaysia, and parts of Oceana. In Micronesia: Mariana Islands—Pagan, Saipan, Tinian, Guam; Palau—exact locality unknown; Caroline Islands—Yap.

Remarks.—The Tufted Duck is a winter migrant to western Micronesia. It has been recorded only a few times and may be an irregular visitor. Flavin observed a duck, which he thought to be of this species, at Guam on January 19, 1946. Marshall (1949:221) reports that two Tufted Ducks were seen at Lake Hagoi in April 1945.

Aythya valisineria (Wilson)

Canvasback

Anas valisineria Wilson, Amer. Ornith., 8, 1814, p. 103, pl. 70, f. 5. (Type locality, Eastern United States.)

Nyroca valilisineria Reichenow, Ornith. Monatsber., 1901, p. 17 (Jaluit); Schnee, Ornith. Monatsber., 1901, p. 131 (Marshalls); idem, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln).

Nyroca valisineria Phillips, Nat. Hist. Ducks, 3, 1923, p. 124 (Marshall Islands).

Aythya valisineria Hand-list Japanese Birds, 3d ed., 1942, p. 207 (Marshall Islands).

Geographic range.—Breeds in northwestern and northcentral North America. Winters south to Gulf States, Florida and Mexico. In Micronesia: Marshall Islands—Jaluit.

Remarks.—Reichenow (1901:17) and Schnee (1901:131) reported three species of American ducks (Aythya valisineria, Anas acuta tzitzihoa and Anas crecca carolinensis) in the Marshalls in October, 1899, and May, 1900. These species may be stragglers to eastern Micronesia.

Accipiter soloënsis (Horsfield)

Chinese Goshawk

Falco Soloënsis Horsfield, Trans. Linn. Soc. London, 13, 1821, p. 137. (Type locality, Java.)

Accipiter soloënsis Hand-list Japanese Birds, rev., 1932, p. 182 (Yap); Hand-list Japanese Birds, 3d ed., 1942, p. 203 (Yap, Rota); Mayr, Birds Southwest Pacific, 1945, p. 302 (Yap).

Geographic range.—Breeds in northern China south to Kwangtung. Winters to Malaysia. In Micronesia: Mariana Islands—Rota; Caroline Islands—Yap.

Remarks.—The Chinese Goshawk is a winter visitor to Micronesia and has been recorded at Rota and Yap. The NAMRU2 party saw several unidentified hawks in Micronesia in 1945. At Mt. Tenjo, Guam, Muennink saw a small hawk, resembling an accipiter, darting at swiftlets on June 8, 1945. At Angaur, the writer saw a small hawk flying through heavy vegetation along the rugged coast line on September 21, 1945. A hawk "Butio(?)" was reported at Saipan in 1945 by Moran (1946:262); this hawk may have been Butastur indicus (Gmelin). Marshall (1949:221) reports seeing "three kinds of hawks" on Palau in November, 1945. Obviously, further observations and collecting will increase our knowledge of the known number of kinds of hawks which visit Micronesia.

Accipiter virgatus gularis (Temminck and Schlegel)

Asiatic Sparrow Hawk

Astur (Nisus) gularis Temminck and Schlegel, in Siebold, Fauna Japon., Aves, 1845, p. 5, pl. 2. (Type locality, Japan.)

Accipiter nisoides Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 7, 1895, p. 166 (Guam); Hartert, Novit. Zool., 5, 1898, p. 51 (Marianne); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 44 (Guam); Safford, Osprey, 1902, p. 70 (Marianas).

Accipiter gularis Kuroda, in Momiyama, Birds Micronesia, 1922, p. 39 (Guam).

Accipiter virgatus gularis Hand-list Japanese Birds, rev., 1932, p. 182 (Guam); Hand-list Japanese Birds, 3d ed., 1942, p. 203 (Guam); Mayr, Birds Southwest Pacific, 1945, p. 302 (Micronesia).

Accipiter virgatus nisoides Bryan, Guam. Rec., vol. 13, no. 2, 1936, p. 15 (Guam).

Geographic range.—Breeds in Japan and northern China. Winters south to Philippines and Malaysia. In Micronesia: Mariana Islands—Guam.

Remarks.—Oustalet (1895:166) records a male bird shot by Marche at Guam in October, 1887. Seale (1901:44) records a specimen taken at Guam by Owston's Japanese collectors. These are the only records found for Micronesia, and the hawk may be classed as a casual winter visitor. Strophlet (1946:535) observed "a small light-throated" falcon at Guam on November 7, 1945, which may have been of this species.

Pandion haliaetus melvillensis Mathews

Osprey

Pandion haliaëtus melvillensis Mathews, Australian Avium Rec., 1, 1912, p. 34. (Type locality, Melville Island.)

Pandion leucocephalus Finsch, Journ. Mus. Godeffroy, 8, 1875, p. 49 (Palau).

Pandion haliaetus leucocephalus Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 1 (Pelew).

Pandion haliaëtus cristatus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 40 (Pelew); Hand-list Japanese Birds, rev., 1932, p. 182 (Pelew); Hand-list Japanese Birds, 3d ed., 1942, p. 203 (Palau).

Pandion haliaëtus melvillensis Mayr, Birds Southwest Pacific, 1945, pp. 55, 286 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 46 (Guam, Palau).

Geographic range.—Malaysia, northern Australia, Melanesia. In Micronesia: Mariana Islands—Guam; Palau Islands—Peleliu.

Remarks.—The Osprey was first recorded at Palau by Finsch (1875:49). The author (1948:46) cites records obtained by C. K. Dorsey at Peleliu in 1944 and 1945. Dorsey saw the Osprey on several occasions; the NAMRU2 party did not find the bird while on their stay there in August and September, 1945. B. V. Travis of NAMRU2 saw an Osprey at Agaña Bay, Guam, in December, 1945. He observed the bird to be carrying a fish in its talons. Flavin observed the Osprey at Guam on January 28, 1945, and on December 23, 1945. Mayr (1945a:286) says that the Osprey apparently breeds at Palau. The bird seen in the Marianas may have been P. h. haliaetus (Linnaeus), a visitor from Asia, which is known to winter in the Philippines and adjacent areas.

The Osprey is the only resident member of the order Falconiformes, and it is principally a fish eater. The few records of mammal and bird eating hawks in Micronesia indicate that predation on insular vertebrate populations from this source is at a minimum. The absence of this predation may have a pronounced effect on the resident land birds, particularly from the standpoint of the perpetuation of nonadaptive mutations, which might be "weeded out" under what might be considered as normal predatory pressure in continental bird populations.

Falco peregrinus japonensis Gmelin

Peregrine Falcon

Falco japonensis Gmelin, Syst. Nat., 1, pt. 1, 1788, p. 257. (Type locality, Off the coast of Japan.)

Falco peregrinus Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 90 (Mackenzie); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 122 (Yap); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 4, 8 (Palau); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 391 (Yap); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 1 (Yap, Pelew); Hand-list Japanese Birds, rev. 1932, p. 182 (Yap, Palau); Hand-list Japanese Birds, 3d ed., 1942, p. 202 (Yap, Palau); Mayr, Birds Southwest Pacific, 1945, p. 302 (Yap, Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 46 (Guam).

?Falco peregrinus calidus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 40 (Yap, Pelew).

Geographic range.—Breeds in northern Asia. Winters to southern Asia, Malaysia and Melanesia. In Micronesia: Mariana Islands—Guam; Palau Islands—exact locality unknown; Caroline Islands—Yap.

Remarks.—The Peregrine Falcon may be classed as a casual winter visitor to Micronesia. It has been recorded by Hartlaub and Finsch at Yap and Palau. A specimen from Yap was taken by Kubary in November, 1870. On November 2, 1945, at Guam as previously recorded (Baker, 1948:46) Irvin O. Buss saw a falcon alight on the superstructure of his ship. He watched it catch and eat a Common Noddy (Anous stolidus). As the ship approached the island, the bird flew to the rugged cliffs near Facpi Point. Strophlet (1946:535) saw a large falcon, "presumed to be a Duck Hawk," at Guam on November 16, 1945. Possibly these two observers saw the same bird. In July, 1945, Flavin observed a Peregrine Falcon at Guam. F. p. fruitii Momiyama, which is known from the Volcano Islands, may occur in Micronesia.

Megapodius lapérouse senex Hartlaub

Micronesian Megapode

Megapodius senex Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 820. (Type locality, Pelew Islands.)

Megapodius senex Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 7, 118 (Pelew); Gray, Hand-list Birds, 2, 1870, p. 256 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 103 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 29, pl. 5, fig. 2, 3 (Palau); Giebel, Thes. Ornith., 2, 1875, p. 547 (Pelew); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 407 (Palau); Oustalet, Ann. Sci. Nat., (6), art. 2, 1881, pp. 63, 140, 145, 171, 175 (Pelew); Tristram, Cat. Birds, 1889, p. 30 (Pelew); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 58 (Pelew); Oustalet, Ann. Sci. Nat. Zool., 11, 1891, p. 196 (Peleu); idem, Nouv. Arch Mus. Hist. Nat. Paris, (3), 8, 1896, p. 30 (Palaos); Ogilvie-Grant, Hand-book Game-birds, 2, 1897, p. 182 (Pelew); Hartert, Novit. Zool., 5, 1898, p. 62 (Pelew); Bolau, Mitteil, Naturhist. Mus. Hamburg, 1898, p. 69 (Palau); Finsch, Sammlung wissensch. Vorträge, 14 ser., 1900, p. 659 (Palau); Matschie, Journ. f. Ornith., 1901, p. 113 (Palau); Lister, Proc. Zool. Soc. London, 1911, p. 757 (Pelew).

Megapodius laperousii Ogilvie-Grant (part), Cat. Birds British Mus., 22, 1893, p. 460 (Pelew); Takastukasa and Kuroda, Tori, 1, 1915, p. 51 (Pelew); Kuroda, Dobutsu. Zasshi, 27, 1915, p. 390 (Pelew); idem, Dobutsu. Zasshi, 28, 1916, p. 69 (Pelew).

Megapodius laperousi Seale (part), Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 39 (Pelew); Safford (part), The Plant World, 7, 1904, p. 265 (Pelew); Uchida, Annot. Zool. Japon., 9, 1918, pp. 486, 487 (Palau).

Megapodius laperousii var. senex Dubois, Syn. Avium, 2, 1904, p. 787 (Pelew).

M[egapodius] lapeyrousei Reichenow (part), Die Vögel, 1, 1913, p. 273 (Palauinseln).

Megapodius laperousei senex Kuroda, in Momiyama, Birds Micronesia, 1922, p. 40 (Pelew).

Megapodius lapérouse senex Mathews, Syst. Avium Australasianarum, 1, 1927, p. 14 (Pelew); Takastukasa, Birds Nippon, vol. 1, pt. 1, 1932, p. 13, pl. 4, 5 (Pelew); Yamashina, Tori, 7, 1932, p. 412 (Ngesebus, Auror, Peliliu); Hand-list Japanese Birds, rev., 1932, p. 198 (Palau); Peters, Check-list Birds World, 2, 1934, p. 6 (Palau); Yamashina, Tori, 10, 1940, p. 679 (Gayangas, Arumidin); Amadon, Amer. Mus. Novit., no. 1175, 1942, p. 9 (Palau); Mayr, Birds Southwest Pacific, 1945, p. 286 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 46 (Garakayo, Peleliu, Ngabad).

Megapodius la pérouse senex Hand-list Japanese Birds, 3d ed., 1942, p. 223 (Babelthuap, Koror, Auror, Ngesebus, Peliliu, Gayangas, Arumidin).

Megapodius laperouse Wharton and Hardcastle, Journ. Parasitology, 32, 1946, p. 294 (Garakayo).

Geographic range.—Micronesia: Palau Islands—Babelthuap, Koror, Auror, Kayangel, Garakayo, Ngesebus, Peleliu, Ngabad, Gayangas, Arumidin.

Characters.—Adult: A small megapode with top of head near "mouse gray"; forehead, sides of face and neck, chin, and throat thinly covered with feathers of the same color; mantle and upper breast grayish-black becoming dark olive-brown on wings; lower back, rump and upper tail-coverts dark brown; tail blackish-brown; underparts grayish-brown, lighter on midline of belly; under wings dark brown; exposed skin of head reddish to yellowish-red; bill yellowish, basally blackish; legs yellowish; feet and claws black; iris tan.

Measurements.—Measurements of three adult males: wing, 178, 182, 188; tail, 55, 63; culmen, 22.7, 23.3; tarsus, 55, 56, 57; of seven adult females: wing, 171-189 (182); tail, 46-68 (58); culmen, 25-30 (27); tarsus, 45-60 (55). Takatsukasa (1932:14) lists the following measurements: males—wing, 176-181; tail, 59-67; culmen, 25.5-26.0; tarsus, 58-61; females—wing, 177-187; tail, 62-68; culmen, 24.0-26.0; tarsus, 55-58.

Specimens examined.—Total number, 23 (11 males, 8 females, 4 unsexed), as follows: Palau Islands, USNM—Koror, 1 (Nov. 28)—Garakayo, 5 (Sept. 17, 18, 19)—Peleliu, 2 (Aug. 31, Sept. 1)—Ngabad, 1 (Sept. 11); AMNH—Palau, 16 (Nov., Dec., not dated).

Nesting.—The megapodes do not incubate their eggs, but the female deposits them in a moundlike structure of sand, volcanic ash, and forest litter or some other type of soil in which there is warmth sufficient to hatch the eggs after an extended period (perhaps 40 days or more) without further attention from the parent bird. The young dig out and lead an independent existence. Several megapodes may utilize one nest site, which ordinarily is at a low elevation near a beach or lagoon.

The NAMRU2 party obtained two downy chicks at Gayakayo Island on September 18 and 19, 1945. A female taken on September 1 at Peleliu contained large eggs. Coultas obtained two chicks (one in postnatal molt) in November and December, 1931. Kubary, as quoted by Takatsukasa (1932:15), says that eggs may be found in the mounds throughout the year at Palau but are found most numerously in the south-east monsoon (April to November). Yamashina (1932a:412) reports on eggs taken in 1932 as follows: eight eggs from Auror Island on January 15; one egg from Ngesebus Island on January 16; and four eggs from Peleliu Island on January 16. Takatsukasa (1932:15) states that eggs are most numerous in the mounds in the months of May and June. The chicks obtained by NAMRU2 in September were of such a size as to suggest that they too had been laid in June.

Takatsukasa (1932:15) comments, "Whilst Dr. Yaichir[=o] Okada was in the Pelew Group, he found two nests on Kajangel Island, which is an uninhabited island about twelve sea-miles southeast of the island of Malacal. He says that he found two nests, one of which was obsolete and the other was in use.

The first one was oval in shape; the diameter of the largest part was twenty-four feet, and the smallest part was twenty feet, and it had a height of four feet. The second one was fan-shaped, as an obstacle existed at one side of the nest, and its diameter was twelve feet and the height was a little more than four feet, and the native whom he asked to dig out the eggs got three. One of the eggs contained a well-advanced embryo and the others were not so advanced as the first one. This distance from the top of the mound to the spot where the eggs were laid was about two and a half feet, and the natives made a great deal of effort to get these eggs. These nests were found in the bush by the natives." The NAMRU2 party observed a mound on Ngabad Island, a small islet near Peleliu, on September 11. It was much like those described by Takatsukasa, being approximately six feet high and some twelve or fifteen feet across. It was not excavated.

Molt.—Birds taken in August, September and November were molting body feathers. Birds taken in December were molting wing feathers.

Food habits.—Takatsukasa (1932:16) comments, "My collector reports to me that this bird diets on insects and tender shoots which it gets from under the soil by scratching with its large and powerful feet." According to Captain Tetens, as noted by Takatsukasa, the food of the bird consists of insects and berries. Birds taken by the NAMRU2 party had the following food items in their stomachs: adult female—2 cc. seeds, grit; adult female—3 cc. crab parts, grit; adult female—2 cc. seeds, sand; male chick—1 cc. ground food, grit; female chick—1 cc. ground food, grit, in crop 3 cc. small wood roaches (Blattidae).

Parasites.—Wharton and Hardcastle (1946:294) obtained the chigger (Acarina), Neoschöngastia yeomansi, from the megapode at Palau. Uchida (1918:486, 487) found the bird lice (Mallophaga), Goniocotes minor and Lipeurus sinuatus, on megapodes from the Palaus.

Remarks.—The NAMRU2 party arrived at the Palau Islands on August 23, 1945, with little notion that the megapode would be found on the war-torn island of Peleliu. As reported by the author (1946b:209 and 1948:46) we found birds in small numbers in the relatively undisturbed areas of rough coral covered by jungle and a few birds in the heavy matting of viny and brushy vegetation which was rapidly covering the battlefields. The finding of a higher population on the more isolated and relatively undisturbed offshore islets (Ngabad, Garakayo) by the NAMRU2 party was an observation similar to those of Takatsukasa (1932:15, 16) and Coultas (field notes). Takatsukasa (1932:16) remarks, "Dr. Finsch said that this Megapode frequents nearly all the islands of the Pelew Group ... but it is very noticeable that this bird has either disappeared, or only very rarely exists in the following islands: Koror, Ngarekobasanga, and especially the main island of Babelthuap." He quotes Otto Finsch as remarking that, "It seems that the bird occasionally moves from one island to another, as the bird is a good flier." Takatsukasa continues, "According to Tetens, this Megapode runs very swiftly among the bushes, and when it is startled it takes to the nearest tree.... Captain Wilson says nothing about the Megapode, but Dr. Finsch wrote that Captain Wilson is probably referring to the egg of this bird under 'Wild Fowls,' when he said that the natives of the Palaus do not eat the flesh of the birds, but they go to the woods and bring back the eggs; they do not appreciate the newly laid eggs, but they consider it as a delicacy to swallow the well advanced embryo."

The NAMRU2 party found the birds to prefer rough, coral jungle where there was considerable heavy undergrowth and ground litter. The birds were located by their loud screeches and cackles but were difficult to stalk. It was best to remain quiet and let them approach within shooting distance. Young chicks were extremely active and wild. One of the two chicks taken at Garakayo was obtained by a fortunate shot as the bird was flying rapidly through the brush. The natives use them as food, and I learned of one serviceman who had worked out a technique for trapping the birds. He traded the live birds to the natives for island souvenirs. As Wilson and Takatsukasa note, the natives apparently prefer the eggs to the adults as food, and in normal times of food abundance they probably do not molest the adults but hunt for their eggs. This seems logical, since if a determined trapping program were in operation by the natives, it should not take many decades to eliminate completely the entire population. On four islands visited by the NAMRU2 party in August and September, 1945, I estimated the following populations: Garakayo—20 to 30; Ngabad—5 to 10; Peleliu—10 to 20; Angaur—less than 10.

Megapodius lapérouse lapérouse Gaimard

Micronesian Megapode

Megapodius La Pérouse Gaimard, Bull. Gén. Univ. Annon. Nouv. Sci., 2, 1823, 451. (Type locality, Tinian, Archipel des Mariannes.)

Megapodius La Pérouse Quoy and Gaimard, Voy. "Uranie," Zool., 1824, pp. 127, 693, Atlas, pl. 33 (Tinian); idem, Ann. Sci. Nat. Paris, 6, 1825, p. 149 (Tinian).

Megapodius La Pérousii Quoy and Gaimard, Voy. "Uranie," Zool., 1824, p. 127, pl. 33 (Tinian); Wagler, Isis, 1829, p. 735 (Tinian, Guam, Rota); Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 46 (Tinian); Oustalet, Ann. Sci. Nat., (6), art. 2, 1881, pp. 63, 138, 140, 143, 171, 175, 176, 177 (Tinian); idem, Le Nat., 1889, p. 261 (Mariannes); idem, Ann. Sci. Nat., Zool., 11, 1891, p. 196 (Tinian, Seypan, Pagon).

Megapodius La Peyrouse Lesson, Man. d'Ornith., 2, 1828, p. 221 (Tinian); idem, Compl. de Buffon, 2d ed., 2, Ois., 1838, p. 255 and accompanying plate (Tinian).

Megapodius laperousii Lesson, Traité d'Ornith., 1831, p. 478 (Mariannes); Gray, Hand-list Birds, 2, 1870, p. 256 (Marian); Ogilvie-Grant, Hand-book Game-birds, 2, 1897, p. 183 (Marianne); Dubois, Syn. Avium, 2, 1904, p. 787 (Mariannes); Lister, Proc. Zool. Soc. London, 1911, p. 757 (Marianne).

Megapodius Lapeyrousii Hartlaub, Journ. f. Ornith., 1854, p. 167 (Mariannen).

Megapodius La Peyrousii Reichenbach, Tauben, 1861, p. 5 (Marianen).

Megapodius la-perousi Gray, Proc. Zool. Soc. London, 1864, p. 43 (Guam, Botta, Tinian).

Megapodius laperousi Giebel, Thes. Ornith., 2, 1875, p. 547 (Marianae); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 39 (Marianas); Safford; Osprey, 1902, p. 68 (Tinian); idem, The Plant World, 7, 1904, p. 265 (Tinian); idem, Contr. U. S. Nat. Herb., 9, 1905, p. 78 (Rota, Saipan, Pagan, Agrigan); Schnee, Zeitschr, f. Naturwisch., 82, 1912, p. 467 (Marianen); Prowazek, Die deutschen Marianen, 1913, pp. 47, 101 (Marianen); Linsley, Guam, Rec., vol. 12, no. 8, 1935, p. 249 (Rota, Saipan, Pagan, Agrigan).

Megapodius perousei Finsch, Journ. Mus. Godeffroy, 8, 1875, p. 30 (Marianen); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 58 (Guam, Botta, Tinian, Pagon).

Megapodius laperousii Ogilvie-Grant (part), Cat. Birds British Mus., 22, 1893, p. 460 (Marianne).

Megapodius la perousei Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 26 (Saypan, Pagan, Rota, Agrigan, Tinian).

Megapodius laperouse Hartert, Novit. Zool., 5, 1898, p. 61 (Saipan, Tinian, Rota, Guam).

Megapodius laperousei Finsch, Sammlung wissensch. Vorträge, 14 ser., 1900, p. 660 (Marianen); Prowazek, Die deutschen Marianen, 1913, p. 87 (Marianen).

Megapodius lapeyrouse Matschie, Journ. f. Ornith., 1901, p. 113 (Guam, Saipan).

M[egapodius] lapeyrousei Reichenow (part), Die Vögel, 1, 1913, p. 273 (Mariannen).

Megapodius laperousei laperousei Kuroda, in Momiyama, Birds Micronesia, 1922, p. 40 (Guam, Saipan, Rota, Tinian, Pagan, Agrigan).

Megapodius lapérouse lapérouse Mathews, Syst. Avium Australasianarum, 1, 1927, p. 16 (Marianas); Takatsukasa, Birds Nippon, vol. 1, pt. 1, 1932, p. 6, pl. 4, 5 (Marianne); Yamashina, Tori, 7, 1932, p. 411 (Pagan Agrigan); Hand-list Japanese Birds, rev., 1932, p. 198 (Marianas); Peters, Check-list Birds World, 2, 1934, p. 7 (Marianne Islands); Yamashina, Tori, 10, 1940, p. 679 (Assongsong); Amadon, Amer. Mus. Novit., no. 1175, 1942, p. 9 (Asuncion, Saipan, Guam); Mayr, Birds Southwest Pacific, 1945, p. 286 (Marianas).

Megapodius laperousi laperousi Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam).

Megapodius la pérouse la pérouse Hand-list Japanese Birds, 3d ed., 1942, p. 223 (Assongsong, Agrigan, Pagan, Almagan, Saipan, Tinian, Agiguan, Rota, Guam).

Geographic range.—Micronesia: Mariana Islands—Asuncion, Agrihan, Pagan, Almagan, Saipan, Tinian, Agiguan, Rota, Guam. Probably extinct on Saipan, Tinian, Rota, Guam.

Characters.—Adult: Resembles M. l. senex, but crown slightly darker gray; back, wing-coverts and scapulars more heavily washed with olivaceous-brown; mantle less slate; underparts paler and more brownish, especially belly. (Note—The specimens examined from the Marianas are old and rather worn in appearance.)

Measurements.—Two males measure: wing 180?, 182?; tail 62, 63; tarsus 55, 55; three females: wing 181?, 181?; tail 55, 59, 62; tarsus 54, 54, 56. Takatsukasa (1932: 10) lists the following measurements: males—wing, 155-169; tail, 54-62; culmen, 22.5-24; tarsus, 51-54; females—wing, 158-170; tail, 56-65; culmen, 23-25; tarsus, 50-55.

Specimens examined.—Total number, 10 (3 males, 4 females, 3 unsexed), as follows: Mariana Islands, AMNH—Guam, 1 (June 6)—Saipan, 6 (1895)—Asuncion, 3 (1904).

Nesting.—Concerning the nest of the Micronesian Megapode in the Marianas, Takatsukasa (1932:10) writes: "The nest is a large mound of sand mixed with grass and is made in the wooded land along the seashore. The mound is over one hundred feet in circumference and a few yards in height, and is built by the united efforts of the male and female, by scratching sand and grass with their large feet. The eggs are laid in this mound and they are hatched by the heat of the sun and that produced by the fermentation of the grass, and they are never hatched by the parent birds. The egg is of a pale brown, but always stained by nesting materials."

Takatsukasa (1932:11) quotes Oustalet as follows: "Specimens collected by Mr. Marche have proved that the breeding season of La Pérouse's Megapode is rather long, like the other species of the same family, it begins to breed in January or February and ends in June. Accordingly, in this period the eggs just laid, the chicks, the young and adult can be seen at one place, but Mr. Marche did not obtain any egg." Hartert (1898:61) records a chick taken on July 17. Yamashina (1932a: 411) records eggs taken in 1931 as follows: two eggs from Pagan, February 17; three eggs from Pagan, May 15; four eggs from Agrihan, June 24. The breeding season for both of the incubator birds, M. l. senex and M. l. lapérouse, is apparently from about January to August.

Remarks.—The Micronesian Megapode was first taken in the Marianas by the expedition of the Uranie. Bérard, a member of the expedition, obtained the bird at Tinian in December, 1820. Quoy and Gaimard (1824:27), who studied the birds of this expedition, reported that according to native tradition the species was in former times widely distributed in the Marianas and domesticated by the ancient people of the islands, but that in 1819 and 1820 the birds were not numerous on Tinian and not found on Guam and Rota. Marche (in Oustalet, 1896:27) obtained twenty-three birds at Saipan, one from Rota, two from Agrihan, and five from Pagan in 1887, 1888, and 1889; it is apparent that Quoy and Gaimard missed the bird at Rota. Marche was of the opinion that the megapodes were never domesticated and that they would probably not last much longer at Saipan and Rota owing to the incessant hunting for them by the natives. As in the Palaus, the natives apparently prefer the eggs to the adults. The latest collections of these birds in the Marianas were made by the Japanese. Yamashina (1932:411) obtained eggs in 1931 at Pagan and Agrihan, and again in 1940. He (1940:679) reported birds at Assongsong (Asuncion). Takatsukasa (1932:12) says, "A collector, working for Marquis Yamashina and myself, lately procured many specimens in Saipan and Pagan." Linsley (1935:249, 250) in searching for the megapode at Guam found little evidence of the birds. He interviewed people between the ages of forty-five and eighty and only two or three remembered seeing the bird. He said he saw one or two cross the road; but I suspect that they might have been rails (Rallus owstoni). Service personnel stationed at various islands in the Marianas during the late war have not reported the birds. The NAMRU2 party found no trace of the bird at Guam or Rota. Joe T. Marshall, Jr. (1949:203), did not find the bird at Saipan, Tinian, or Guam in 1945. Its status on Agiguan is unknown; isolated Japanese troops present on this small island from the time of the American invasion (1944) until the armistice (1945) may have used the birds for food and depleted the population seriously. At present the birds apparently still occur on islands in the northern Marianas. It seems that if these birds are to survive, they must be given some protection.

Evolutionary history.—The genus Megapodius consists, according to Peters (1934:1-7), of nine species which are distributed through the islands from the Philippines and Borneo to Australia and Melanesia. These have been redesignated under three specific names by Mayr (1938). Outlying forms occur in the Nicobar Group to the west and in Tonga (Niuafou Island) in the east and in the Palaus and Marianas to the extreme northeast. Lister (1911:757) is of the opinion that the megapodes may have reached these outlying islands by having been transported by the natives, by whom the eggs were highly valued as food. This idea is also maintained by Rutland (1896:29-30) and Christian (1926:260). Possibility and not factual evidence support this hypothesis. From their seeming ancestral stocks, M. pritchardii Gray of Niuafou Island and M. lapérouse of Micronesia are remarkably distinct which may indicate their early arrival at these islands and subsequent change from their ancestral stocks.

Like M. pritchardii, the Micronesian species is smaller than its relatives to the southwest and has short, rather rounded wings, although its feet are heavily built whereas those of M. pritchardii are lightly constructed. In comparing these birds with the species of megapode found in the Philippines, Celebes and Melanesia, it seems that both M. pritchardii and M. Lapérouse are closely related to the widespread species, M. freycinet, which may have been ancestral to both. The differences between M. prichardii and M. lapérouse indicate that they represent independent invasions. Nevertheless these megapodes may have had a wider range in Oceania in former times; man may have eliminated the birds from some islands by using their eggs. The eggs are laid in conspicuous mounds which are easily found by man.

M. lapérouse differs from M. freycinet of New Guinea and other parts of Melanesia and the Philippines; its small size, short wing and pearl gray head are distinctive characters. It shows greatest resemblance to the subspecies in Celebes (M. f. gilberti) in size and to the subspecies in the Moluccas (M. f. freycinet) in coloring; possibly M. lapérouse represents stock from one of these regions. Apparently the group as a whole evolved from a center of dispersal in the New Guinea area. Mayr (1942b:167) regarded all the species of Megapodius as belonging to one polytypic species, except M. lapérouse and M. pritchardii, which are allopatric species.

Coturnix chinensis lineata (Scopoli)

Painted Quail

Oriolus lineatus Scopoli, Del. Flor. et Faun. Insubr., fasc. 2, 1786, p. 87. (Type locality, Luzon, ex Sonnerat.)

Excalfactoria sinensis Hartert, Novit. Zool., 5, 1898, p. 61 (Guam); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 37 (Guam); Safford, Osprey, 1902, p. 68 (Guam); idem, Amer. Anthro., 4, 1902, p. 711 (Guam); idem, The Plant World, 7, 1904, p. 265 (Guam); idem, Contr. U. S. Nat. Herb., 9, 1905, p. 78 (Guam); Cox, Island of Guam, 1917, p. 21 (Guam); Nelson, Proc. 1st Pan-Pacific Sci. Conf., 1921, p. 273 (Guam).

Excalfactoria chinensis lineata Wetmore, in Townsend and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, p. 176 (Guam); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 41 (Guam); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 20 (Marianne); Hand-list Japanese Birds, rev., 1932, p. 198 (Guam); Peters, Check-list Birds World, 2, 1934, p. 96 (Guam); Bryan, Guam. Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Hand-list Japanese Birds, 3d ed., 1942, p. 223 (Guam); Mayr, Birds Southwest Pacific, 1945, p. 287 (Guam).

Excalfactoria chinensis Strophlet, Auk, 1946, p. 536 (Guam).

Coturnix chinensis lineata Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 47 (Guam).

Geographic range.—Philippines and parts of Malaysia. In Micronesia: Mariana Islands—Guam (introduced).

Characters.—Adult: A small quail with upper parts brown splotched with black and streaked with buff; males with face and throat black surrounded by white line, upper breast blue gray, lower breast, belly and under tail-coverts and tail near "burnt sienna"; females lighter than males, underparts pale brown, mottled with blackish on breast and sides of body; bill dark lead colored, feet yellow.

Measurements.—Three adult males from Guam measure: wing, 66, 67, 67; culmen, 9.2, 10.0, 10.3; tarsus, 18.1, 18.7, 22.6.

Weights.—Two adult males taken by NAMRU2 at Guam weigh 34.5 and 35.5 grams.

Specimens examined.—Total number, 3 males from Mariana Islands, USNM—Guam (Feb. 24, June 13, 28).

Remarks.—Seale (1901:37) writes that the Painted Quail was introduced to Guam from Manila, or the island of Luzon in the Philippine Islands, by Captain Pedro Duarty of the Spanish Army in 1894. It was a successful introduction; the bird is well adapted to the grasslands, open hillsides, and fallow rice paddies. The bird appears to offer no serious competition to native species, because there are few native birds which depend largely on this habitat. The NAMRU2 party obtained specimens at Mt. Santa Rosa and near Agat; others were seen as singles or pairs near Umatac and on Mount Tenjo. Strophlet (1946:536) observed the birds in the southern part of Guam in 1945. He found them as singles or pairs in the months of September, October and November. Wilfred Crabb reported a covey of seven birds in June, 1945. Two males taken in June had enlarged testes. Seale (1901:37) obtained a nest of seven eggs.

Gallus gallus (Linnaeus)

Red Jungle Fowl

Phasianus Gallus Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 158. (Type locality, "India orientali, Pouli condor etc.," restricted to Pulo Condor, off mouths of the Mekong.)

Phasianus Gallus Kittlitz, Obser. Zool., in Lutké, Voy. "Le Séniavine," 3, 1836, p. 284 (Ualan = Kusaie).

Gallus bankiva Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 103 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 29 (Palau); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, pp. 281, 298, 353 (Ponapé, Mortlock, Ruk); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 59 (Pelew, Caroline, Marianne, Marshall); Oustalet, Nouv. Arch. Mus. Hist. Nat., Paris, (3), 8, 1896, p. 25 (Saypan, Palaos, Marshall); Hartert, Novit. Zool., 5, 1898, p. 61 (Saipan); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 38 (Marianas); Safford, Osprey, 1902, p. 70 (Marianas).

Gallus ferrugineus Finsch, Proc. Zool. Soc. London, 1877 (1878), p. 780 (Ponapé); idem, Ibis, 1881, p. 114 (Ponapé, Kushai).

Gallus gallus bankiva Kuroda, in Momiyama, Birds Micronesia, 1922, p. 41 (Saipan, Pelew, Ponapé, Marshall).

Gallus gallus Mathews, Syst. Avium Australasianarum, 1, 1927, p. 21 (Micronesia); Cram, Bull. U. S. Nat. Mus., 140, 1927, pp. 238, 328 (Guam); Bequaert, Mushi, 12, 1939, p. 81 (Kusaie); idem, Occ. Papers Bernice P. Bishop Mus., 16, 1941, p. 266 (Kusaie); Mayr, Birds Southwest Pacific, 1945, pp. 57, 286 (Marianas, Carolines, Palaus); Wharton and Hardcastle, Journ. Parasitology, 32, 1946, pp. 294, 310 (Ulithi, Garakayo); Stott, Auk, 1947, p. 525 (Saipan).

Gallus gallus domesticus Hand-list Japanese Birds, rev., 1932, p. 198 (Marianas, Palaus, Carolines, Marshalls).

Gallus gallus micronesiae Hachisuka, Tori, 10, 1939 (1940), p. 600 (Type locality, Truk, also from Pelew, Rota, Yap, Ponapé); Hand-list Japanese Birds, 3d ed., 1942, p. 222 (Saipan, Rota, Babelthuap, Koror, Yap, Truk, Lukunor, Ponapé, Kusaie, Marshalls).

Gallus gallus gallus Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 47 (Peleliu, Ngabad, Garakayo, Ulithi, Truk).

Geographic range.—Southeastern Asia and Malaysia; introduced into many islands of Oceana. In Micronesia: Mariana Islands—Saipan, Rota; Palau Islands—Kayangel, Babelthuap, Koror, Garakayo, Peleliu, Ngabad, Angaur; Caroline Islands—Ulithi, Yap, Truk, Lukunor, Ponapé, Kusaie; Marshall Islands—exact locality not known.

Specimens examined.—Total number, 3 (1 male, 2 females) as follows: Palau Islands, USNM—Garakayo, 1 (Sept. 19)—Peleliu, 1 (Sept. 13)—Ngabad, 1 (Sept. 11).

Parasites.—Cram (1927:238, 328) found the round worms (Nematoda), Dispharnyx nasuta and Oxyspirura mansoni in birds from Guam. Bequaert (1939:81 and 1941:266) found the fly (Hippoboscidae) Ornithoctona plicata, on fowl from Kusaie. Wharton and Hardcastle (1946:294, 310) obtained the chiggers (Acarina), Neoschöngastia yeomansi and N. ewingi from fowl at Ulithi and Garakayo.

Remarks.—The Red Jungle Fowl has been introduced in Micronesia, as it has been in other parts of Oceania. It is found on many of the islands of Micronesia, including the volcanic islands and the atolls. The NAMRU2 party did not find feral fowl at Guam but found the wary birds at Ulithi and in the Palaus. The birds at Ulithi were small and of a mixed breed. At Palau some fine examples of typical jungle fowl were observed. Coultas obtained similar specimens at Ponapé and Kusaie. The natives have apparently allowed these birds to go wild, but catch them for food. These wild stocks may represent the earlier "liberations" while domestic fowl kept by natives at present appear to include several other breeds probably obtained from Europeans.

The committee that prepared the Hand-list of Japanese Birds (Hachisuka et al., 1942:222) points out that although many ornithologists believe the Red Jungle Fowl to be introduced in Micronesia and other parts of Oceania, it is their opinion (based on a series of more than 100 skins before them) that the population in Micronesia is racially distinct. They further comment, as did Hachisuka (1939b:600), that one may find hybrids between these birds and the domestic fowl belonging to the native peoples; this is commonly seen on the more populated islands such as Koror and Saipan. I have no doubt that these skins show distinct features; nevertheless, I am reluctant to recognize these by subspecific name, since the birds may be a mixture of domestic strains introduced by man at different times after the jungle fowl was first brought by the early Micronesians. It seems that the production of hybrids between the feral and domestic fowl, which we find there today, may have been going on ever since the European colonists arrived with their fancy breeds of chickens.

Phasianus colchicus Linnaeus

Ring-necked Pheasant

Phasianus colchicus Linnaeus, Syst. Nat., ed. 10, 1, 1758, p. 158. (Type locality, Africa, Asia = Rion.)

Phasianus torquatus Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 47 (Guam).

Geographic range.—Eastern China and northeastern Tonkin. Widely introduced into North America, Europe, and New Zealand. In Micronesia: Mariana Islands—Guam (introduced).

Remarks.—On July 4, 1945, fifty-seven Ring-necked Pheasants (sixteen cocks and forty-one hens) were liberated at Guam by personnel of the U. S. Navy. The birds were eleven weeks old when released, having been brought by plane from the hatcheries of the State Division of Game and Fish in California. Twenty-four birds were liberated at the site of CincPoa headquarters near Mt. Tenjo. Thirty-three were placed near the FEA dairy farm, approximately one and one-fourth miles west of Price School. One month after release the birds were present at the liberation sites, although there were reports that some had drifted as far away as a mile or more. The birds were not banded. This liberation has been reported on by Quinn (1946:32-33) and by the author (1946b:211 and 1948:47). In using the name P. colchicus, I am following Delacour (in McAtee, 1945:8) and the twenty-third supplement to the American Ornithologists' Union check-list of North American birds (Auk, 65, 1948:440).

Rallus philippensis pelewensis (Mayr)

Banded Rail

Hypotaenidia philippensis pelewensis Mayr, Amer. Mus. Novit., no. 609, 1933, p. 3. (Type locality, Palau Islands.)

Rallus philippensis Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 831 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 37 (Palau); idem, Proc. Zool. Soc. London, 1877, p. 587 (Palau); Wiglesworth (part), Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 59 (Pelew); Finsch, Deut. Ver. zum Schulze der Vogelwelt, 18, 1893, p. 459, Palau).

Rallus pectoralis Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 8, 117, 118 (Pelew); idem, Proc. Zool. Soc. London, 1872, pp. 89, 107 (Pelew).

Eulabeornis forsteri Gray (part), Hand-list Birds, 3, 1871, p. 57 (Pelew).

Hypotaenidia philippensis Salvadori (part), Ornith. Papuasia, 3, 1882, p. 261 (Pelew); Sharpe (part), Cat. Birds British Mus., 23, 1894, p. 39 (Pelew); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 42 (Pelew).

Eulabeornis philippensis? Mathews, Birds Australia, 1, 1910-1911, p. 199 (Pelew).

Hypotaenidia philippinensis philippensis Hand-list Japanese Birds, rev., 1932, p. 196 (Palau).

Rallus philippensis pelewensis Hand-list Japanese Birds, 3d ed., 1942, p. 220 (Babelthuap, Koror); Mayr, Birds Southwest Pacific, 1945, p. 287 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 48 (Peleliu, Garakayo).

Geographic range.—Micronesia: Palau Islands—Babelthuap, Koror, Arakabesan, Garakayo, Peleliu, Angaur.

Characters.—Adult: A large, slender rail with black crown streaked with brown; superciliary stripe ashy-gray, lighter toward bill; eye stripe brown becoming more rufous behind eye and on nape; chin ashy-gray; throat near "mouse gray" tinged with olive especially toward breast; breast, belly and sides barred with black and white, with a broad "tawny" band on breast; posterior part of belly and vent buffy with some barring; under tail-coverts barred with black, white, and buff; mantle black with feathers subterminally barred with white; back, scapulars, inner wing-coverts, and rump black with white spotting and feathers edged with olive brown; outer wing-coverts, secondaries, and primaries barred with black and rufous with some buffy-white on outer webs; under wing barred black and white with some brownish markings; tail with both bars and blotches of black, white, and buffy-rufous; maxilla horn-colored; mandible yellowish; feet light brown.

R. p. pelewensis resembles R. p. philippensis Linnaeus of the Philippines, but is darker with nape more rufous-brown; upper parts marked with narrower and darker edgings to feathers and with pronounced whitish spotting.

Resembles R. p. chandleri (Mathews) of Celebes, but with wing shorter; more pronounced band on breast; bird darker above and below; rump and upper tail-coverts less spotted.

Measurements.—Specimens in the collection of the United States National Museum measure as follows: four adult males—wing, 130-134 (132); tail, 59-63 (61); full culmen, 30-37 (34); tarsus, 38-45 (43); four adult females—wing, 125-130 (127); tail, 54-61 (58); full culmen, 29-35 (32); tarsus, 38-42 (40). Mayr (1933c:4) lists the following measurements: twelve adult males—127-143 (134.6); tail, 54-65 (60); exposed bill, 25-28 (27.7); tarsus, 41-46 (43.5); three adult females—wing, 129, 136, 136; tail, 56, 57, 58; exposed bill, 23, 24, 25; tarsus, 40, 41, 42.

Specimens examined.—Total number, 27 (18 males, 9 females), as follows: Palau Islands, USNM—Garakayo, 4 (Sept. 18, 19, 20)—Peleliu, 4 (Aug. 27, 28, Sept. 16)—Arakabesan, 1 (Nov. 26); AMNH—exact locality not given, 18 (Oct., Nov., Dec.).

Nesting.—The condition of the gonads in specimens obtained indicates that the breeding season is principally in the fall and winter. Of adult rails taken by Coultas in October, November and December, 1931, 6 of 12 males and 3 or 4 females had enlarged gonads. In September, 1945, the NAMRU2 party obtained two adult males with swollen testes. Marshall (1949:219) recorded breeding in September and November.

Food habits.—Stomachs of rails obtained by the NAMRU2 party contained insects, seeds and small mollusks. Coultas (field notes) notes that the birds eat snails, roots and other vegetable matter.

Remarks.—Rallus philippensis is geographically widespread, being found from Tasmania and Australia north to Malaysia and the Philippines west to Cocos Keeling Island east to Melanesia and western Polynesia and north to the Palau Islands. The species is divisible into several subspecies. The one in the Palaus, although distinctive, does not appear to have undergone a higher degree of differentiation (even though isolated as a small population) than any of the subspecies in Malaysia or Melanesia. Perhaps the form on Palau as well as the relatively undifferentiated Poliolimnas cinereus are rather recent invaders of Micronesia, as compared with Rallus owstoni and Aphanolimnas monasa.

The Banded Rail is less secretive in habits than Rallus owstoni of Guam, and neither was seen to fly. At Angaur, Peleliu and Garakayo, the NAMRU2 party found the rail in areas of swamp and marsh as well as in the rocky uplands; it probably prefers the former habitats. Several rails were observed and shot in open places, but they probably prefer to remain in dense cover. Coultas found the birds at taro patches and swamps. I watched a rail feeding along an open trail on Garakayo. The bird was eating small mollusks and other items which were in the open area. Being a true skulker, the bird would make a quick dash to the feeding place, remain only a few moments, hurriedly return to the protective cover, and then repeat the process. The best means that I found of obtaining these birds was using traps baited with peanut butter and oatmeal. The traps had to be visited frequently or the ants made short work of the captured birds.

Rallus owstoni (Rothschild)

Guam Rail

Hypotaenidia owstoni Rothschild, Novit. Zool., 2, 1895, p. 481. (Type locality, Guam.)

?Rallus philippinus Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 51 (Marian or Ladrone Is.).

Rallus pectoralis Finsch and Hartlaub, Fauna Centralpolynesiens, 1867, p. 157 (Guam).

Eulabeornis forsteri Gray (part), Hand-list Birds, 3, 1871, p. 57 (Marian).

Hypotaenidia philippensis Pelzeln, Ibis, 1873, p. 41 (Marianne Isl.); Salvadori (part), Ornith. Papuasia, 3, 1882, p. 261 (Marianas); Sharpe (part), Cat. Birds British Mus., 23, 1894, p. 39 (Guam).

Rallus philippinus Wiglesworth (part), Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 59 (Guam).

Hypotaenidia owstoni Hartert, Novit. Zool., 5, 1898, p. 62 (Guam); Safford, Osprey, 1902, pp. 41, 67 (Guam); idem, The Plant World, 7, 1904, p. 265 (Guam); Dubois, Syn. Avium, 2, 1904, p. 961 (Mariannes); Safford, Contr. U. S. Nat. Herb., 9, 1905, p. 79 (Guam); Cox, Island of Guam, 1917, p. 21 (Guam); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 42 (Guam); Hartert, Novit. Zool., 34, 1927, p. 22 (Guam); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 84 (Guam); Hand-list Japanese Birds, rev., 1932, p. 196 (Guam).

Hypotaenidia marchei Oustalet, Nouv. Arch. Mus. Hist. Nat., Paris, (3), 8, 1896, p. 32 (Type locality, Guam).

Hypotaenidia oustini Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 30 (Guam).

Rallus owstoni Peters, Check-list Birds World, 2, 1934, p. 166 (Guam); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Hand-list Japanese Birds, 3d ed., 1942, p. 220 (Guam); Mayr, Birds Southwest Pacific, 1945, p. 287 (Guam); idem, Audubon Mag., 47, 1945, p. 279 (Guam); Watson, Raven, 17, 1946, p. 41 (Guam); Strophlet, Auk, 1946, p. 536 (Guam); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 48 (Guam).

Geographic range.—Micronesia: Mariana Islands—Guam.

Characters.—Adult: A large rail with head, neck, and eye stripe near "mummy brown" with feathers on sides of neck tipped with "russet"; superciliary stripe to back of neck, throat and upper breast near "mouse gray"; mantle, back, scapulars, and some upper wing-coverts dark olive-brown becoming browner on rump and upper tail-coverts; wings dark with brownish spots and barred with white; lower breast, abdomen, under tail-coverts, and tail blackish with white barrings; bill lead colored; feet dark brown; tibia brown; iris red.

Measurements.—Four adult males measure: wing, 120-123 (121); tail, 46-54 (50); full culmen, 37-43 (41); tarsus, 47-51 (50); six adult females measure: wing, 108-118 (112); tail, 38-46 (42); full culmen, 36-39 (37); tarsus, 43-47 (45).

Weights.—The NAMRU2 party obtained specimens with the following weights: two adult males 256, 257; four females 147, 153, 210, 252 grams.

Specimens examined.—Total number, 13 (5 males, 6 females, 2 unsexed), from Mariana Islands, USNM—Guam (Jan. 29, May 8, June 19, 20, 23, 28, 30, July 14, 19, 23, Sept. 8).

Nesting.—A nest was found by McElroy of the NAMRU2 party at Guam on October 24, 1945, in dense grass on a hillside near Mount Santa Rosa. The nest contained three eggs, which the author (1948:48) describes as "white with a pinkish cast and a scattering of small spots of colors near 'russet' and near 'pear blue' which are concentrated at the large ends. They measure 37.5 by 29.1, 39.1 by 28.0, and 40.7 by 29.0." Downey, black chicks were found on April 1, May 16, and May 26. M. Dale Arvey found a chick on August 2, 1946, near Tumon Bay. A parent bird with young ones was seen near Merizo on October 2. A male taken on January 26 had enlarged gonads. Seale (1901:30) obtained a black chick in June or July. On the basis of the above observations it seems that the nesting season extends from spring to fall, although Marshall (1949:219) assumes that this rail breeds the year around.

Remarks.—The Guam Rail was first reported by Quoy and Gaimard who called it "Ralê tiklin," but was not described as new until 1895 by Rothschild. It appears to be equally at home in upland grassy areas and in jungle areas. The species was not seen frequently by the NAMRU2 party, although birds were occasionally observed crossing the roads. Few birds were shot; most of the specimens were taken in rat traps, which may be the most satisfactory method of obtaining them. Coultas took his specimens with the aid of a dog. On June 19, 1945, a small patch of woodland was being removed by a bulldozer. Four rails, which were hiding in this thicket, were surrounded and three were captured by hand. These birds tried to escape over the cleared ground by running with wings flapping but made no effort to fly. I am inclined to believe, as the natives do, that these birds are virtually incapable of actual flight.

The Guam Rail usually appeared to be a quiet bird, but at Tarague Point on July 12, 1945, I heard its loud penetrating cry; it was a series of rapid screeches. At the same time rapid movement made considerable noise in the undercover. The bird making the call suddenly appeared, either rapidly chasing, or being chased by, another rail. The birds had abandoned their usual skulking habits and had little concern for the observer. I took this to be breeding behavior, comparable to that of some of the North American rails during the mating period.

The Guam Rail is probably not in serious danger of extermination. It is utilized by the natives as food; they capture the bird, using dogs and trail snares. Its skulking habits and ability to inhabit most types of cover on the island should insure its existence for a long time to come.

Evolutionary history.—Rallus owstoni is endemic to the island of Guam with no closely related forms nearby. It is one of the several rails found in the Pacific which live on isolated islands. In comparison with other species in the region, it has some resemblance to both R. torquatus and R. philippensis. In general, the underparts of R. owstoni resemble those of the R. philippensis group, although the upper parts resemble somewhat those of R. torquatus. Certain specimens of R. owstoni have a slight indication of a pale pectoral band. The bill is shorter and heavier than that of R. torquatus, possibly more like that of R. philippensis. The short rounded wing is a distinctive character. The bird came from an ancestral stock possibly resembling R. philippensis and probably originated in the Philippine or Papuan areas. It may have invaded Micronesia at an early date and may have had a wider distribution in the islands in former times. Perhaps this same invasion resulted in the establishment of R. wakensis (Rothschild) at Wake. The supposed route of colonization is shown in [figure 9].