REMARKS ON BEEBE’S ‘TROPICAL WILD LIFE.’
BY THOMAS E. PENARD.
In a previous number of ‘The Auk’ (1918, XXXV, p. 91), Dr. Witmer Stone reviewed briefly this interesting volume published by the New York Zoölogical Society, presenting the first season’s work at the tropical research station, established in British Guiana under the direction of Mr. William Beebe. The results obtained by Mr. Beebe and his associates are of such interest and importance, and the work in general so deserving of the reviewer’s praise, that I feel rather reluctant in offering a few slight corrections. My observations are not intended as criticisms, and I would hardly have thought it worth while to express them, were it not for the fact that the very excellence and authoritative character of Mr. Beebe’s book might perhaps have the effect of creating a few misleading impressions in regard to some minor matters with which it deals.
In Chapter VIII Mr. Beebe gives a list of the birds of the Bartica District, in which, for the sake of completeness, he includes some species collected by Whitely at the same place, and listed by Salvin in ‘The Ibis’ for 1885 and 1886. Twenty-two species are starred to indicate that they are new to the Colony of British Guiana. Of this number, however, at least eighteen have been previously recorded from various localities in the Colony as follows:
Columba plumbea plumbea Vieillot. Listed by Salvin (Ibis, 1886, p. 173) from Bartica Grove and Camacusa. Percival (Birds of the Botanic Gardens, 1893, Argosy reprint, p. 6) says that it is “unfrequent in Gardens, though a common species.” Dawson (Hand-list of the Birds of British Guiana, 1916, p. 51) lists it as a Colonial species. Some of these records may, however, apply to Œnœnas purpureotincta (Ridgway). The form inhabiting British Guiana is Œnœnas plumbea locutrix (Max.).
Ibycter americanus (Boddaert). Bonson (P. Z. S., 1851, p. 56) records it from Br. Guiana under the name of “Red-headed Carracarra.” It is listed by Salvin (l. c., 1886, p. 77) from Bartica Grove and Camacusa; by Quelch (Timehri, 1890, p. 102 and p. 334) from Demerara Falls and Upper Berbice; by Chubb (The Birds of British Guiana, 1916, i., p. 216, McConnell coll.) from Kamakabra River, etc., giving range in Br. Guiana; and by Dawson (l. c., p. 7).
Urochroma batavica (Boddaert). —Lloyd (Timehri, 1895, p. 272, sub nom. Urochroma cingulata) mentions it as formerly very plentiful in the neighborhood of “Groete Creek,” and (l. c., p. 278) gives local range as Essequibo River and N. W. District; F. P. and A. P. Penard (De Vögels van Guyana, 1908, i, p. 523) say these birds are not unfrequently seen in Surinam and Demerara during the Dry Season; Chubb (l. c., p. 336, sub nom. Touit batavica) records specimens from Supenaam River and other localities, and gives range in Br. Guiana; and Dawson (l. c., p. 20) lists it as the “Black-winged Parakeet.”
Ceryle americana americana (Gmelin). Recorded by Salvin (l. c., 1886, p. 60) from Bartica Grove and other localities; by Sharpe (Cat. Birds Br. Mus., 1892, xvii, p. 139) from Demerara River; by Chubb (l. c., p. 348) from Bonasika River, etc., giving range in Br. Guiana; and by Dawson (l. c., p. 16).
Cypseloides fumigatus Streubel. —F. P. and A. P. Penard (l. c., 1910, ii, p. 95) state that there are specimens in the Georgetown Museum, and Dawson (l. c., p. 34) lists it as a Colonial species.
Tapera nævia (Linné).—Schomburgk (Reis. 1848, iii., p. 713, sub nom. Diplopterus galeritus) says that it is abundant in coast regions. Quelch (Timehri, 1891, p. 95; Reprint, p. 27) speaks of it as common in Georgetown; and Percival (l. c., p. 9) states that its frequent plaintive note “Wife-sick” is one of the most familiar garden sounds. It has also been recorded by Salvin (l. c., 1886, p. 64) from Bartica Grove and Roraima; by Shelley (Cat. Birds Br. Mus., 1891, xix, p. 423) from Georgetown; by Chubb (l. c., p. 443) from Ituribisi River, etc., giving range in Br. Guiana; and by Dawson (l. c., p. 23). The Br. Guiana form stands, Tapera nævia nævia (Linné).
Pteroglossus aracari aracari (Linné). —Schomburgk (l. c., p. 720) states that the species is tolerably abundant in Br. Guiana. It has been recorded by Salvin (l. c., 1886, p. 65) from Bartica Grove; by Sclater (Cat. Birds Br. Mus. 1891, xix, p. 138) from Demerara; by Chubb (l. c., p. 458, sub nom. Pteroglossus roraimæ) from Roraima etc., giving range in Br. Guiana; and by Dawson (l. c., p. 22). The form inhabiting Br. Guiana is P. a. atricollis (P. L. S. Müller)—see Bangs and Penard (Bull. M. C. Z., 1918, p. 55).
Chloronerpes rubiginosus (Swainson). —Schomburgk (l. c., p. 715) says he found it throughout Br. Guiana. It has been recorded by Salvin (l. c., 1886, p. 59) from Bartica Grove, Merumé Mountains, and Roraima; by Chubb (l. c., p. 483) from Anarika River, etc., giving range in Br. Guiana; and by Dawson (l. c., p. 24).
Thamnophilus amazonicus Sclater. —Schomburgk (l. c., p. 687) states that it inhabits the low bushes of the coast woods. It has been recorded by Salvin (l. c., 1885, p. 423) from Bartica Grove and Camacusa; by Sclater (Cat. Birds Br. Mus., 1890, xv, p. 199) from Takutu River (Salvin-Godman coll.); by Quelch (Animal Life in Br. Guiana, 1901, p. 182); and by Dawson (l. c., p. 26), who stars the species, indicating that there are no representatives in the Museum at Georgetown. All these authors, except Sclater, refer to this species as Thamnophilus ruficollis [= amazonicus ♀].
Dysithamnus schistaceus (d’Orbigny). F. P. and A. P. Penard (l. c., 1910, ii, p. 308) state that there are specimens in the Museum at Georgetown. Dawson (l. c., p. 26)lists it as a Colonial species.
Automolus infuscatus Sclater. —Recorded by Salvin (l. c., 1885, p. 420, sub nom. Automolus sclateri), from Bartica Grove, stating that the specimens are rather smaller than those from the type locality, with faint indication of striation on the throat; and by Sclater (Cat. Birds Br. Mus. 1890, xv, p. 95, sub nom. Automolus sclateri) from Camacusa and Bartica Grove. Automolus sclateri (Pelzeln) is a pure synonym of Automolus infuscatus Sclater, having been proposed by Pelzeln (Orn. Bras., 1867, i. p. 41) on the assumption that the name Automolus infuscatus was preoccupied by Anabates infuscatus Bonaparte, which, however, proves to be a nomen nudum (Cf. Hellmayr, Nov. Zool., 1905, xii, p. 279). Mr. Beebe lists both infuscatus and cervicalis, apparently considering them two distinct species, the former only being starred as new to the Colony. Hellmayr (Nov. Zool., 1906, xiii, p. 335) says that “the specimens of Automolus sclateri from British Guiana in the British Museum are absolutely identical with the type of P. cervicalis,” and states that the type of P. cervicalis is an immature bird. He lists the Guiana form, which differs from true infuscatus, as Automolus infuscatus cervicalis (Sclater), type locality “Camacusa and Bartica Grove.”
Apparently, then, records of A. infuscatus, A. sclateri, and A. cervicalis, in Br. Guiana, apply to the same bird.
Sclerurus rufigularis Pelzeln. —Hellmayr (Nov. Zool., 1906, xiii, p. 364) mentions an immature bird from Takutu River, Br. Guiana, and says (l. c., p. 365) that there is a specimen in the British Museum collected by Whitely at Bartica Grove. He also says that the Br. Guiana Museum has a ♂ from Ourumee.
Xiphorhynchus guttatoides (Lafresnaye). The form guttatoides of Colombia, is a subspecies of Xiphorhynchus guttatus Lichtenstein, of which the race inhabiting Br. Guiana is X. g. sororius (Berlepsch and Hartert), type locality Perico, Orinoco River. Berlepsch and Hartert (Nov. Zool., 1902, ix, p. 63), who originally described this form as Dendrornis rostripallens sororia, mention a specimen from Quonja, Br. Guiana, coll. Whitely, agreeing with birds from Perico. Schomburgk (l. c., p. 690, sub nom. Dendrocolaptes guttatus) says he found it throughout Br. Guiana; Salvin (l. c., 1885, p. 422), referring to it as Dendrornis guttatoides, records a specimen from Bartica Grove; and Dawson (l. c., p. 29) lists it under the same name. Quelch (Animal Life in Br. Guiana, 1901, p. 177), speaking of Dendrornis pardalotus and Dendrornis guttatoides, says that one or both of these species will invariably be found in collections made in the forest districts.
Elænia guianensis Berlepsch.—The type locality of this species is Camacusa, British Guiana. It has been recorded by Salvin (l. c., 1885, p. 295) as Elainea elegans, from Bartica Grove, Camacusa, etc.; by Sclater (Cat. Birds Br. Mus., 1888, xiv, p. 150) as Elainea gaimardi, from Roraima; and by Dawson (l. c., p. 13) as Myiopagis gaimardi. The Br. Guiana form now stands, Myiopagis gaimardii guianensis (Berlepsch).
Empidochanes fuscatus cabanisi Léotaud. —Recorded by Salvin (l. c., 1885, p. 297, sub nom. Empidochanes olivus) from Bartica Grove; and by Sclater (Cat. Birds Br. Mus., 1888, xiv, p. 224, sub nom. Empidonax oliva), who states that this is the northern form of E. bimaculatus (d’Orb. and Lafr.), adding that he was doubtful whether it was really entitled to the name oliva. The type locality of cabanisi is Trinidad. The form inhabiting Cayenne is Empidochanes fuscatus fumosus Berlepsch, to which we suppose the Surinam bird also belongs.
Riparia riparia (Linné). -Recorded by Salvin (l. c., 1885, p. 206) as Cotile riparia, from Bartica Grove.
Sporophila bouvronides (Lesson). —Brabourne and Chubb (Birds of South America, 1912, i, p. 367) refer S. ocellata (Scl. and Salv.) to this species, and give the type locality Trinidad. References to S. ocellata in Guiana probably apply to the same bird which Mr. Beebe had in hand. Mr. Beebe also lists S. lineola (Linn.). Sharpe (Cat. Birds Br. Mus., 1888, xii, p. 130) lists S. ocellata from Carimang River, Br. Guiana. Dawson (l. c., p. 48) mentions both ocellata and lineola.
Thraupis palmarum palmarum (Wied). Schomburgk (l. c., p. 670, sub nom. Tanagra olivascens) states that it is abundant at the coast. It has been recorded by Salvin (l. c., 1885, p. 210) from Bartica Grove and Roraima; by Quelch (Timehri, 1891, p. 81; Reprint, p. 13) who says it is common in Georgetown, mentioning the species again later (Animal Life in Br. Guiana, 1901, p. 113); by Price (Timehri, 1891, p. 63) who describes the eggs; by Percival (l. c., p. 16) who states that it is “not very often seen in the Gardens, though common among the innumerable cocoanut palms in and about town,” where the writer also has seen it; and by Dawson (l. c., p. 46; and Timehri, 1911, p. 272). The type locality of palmarum is Bahia, and judging from material examined, I would say that birds from Cayenne, Surinam, and Br. Guiana, differ distinctly from true palmarum, and are more nearly allied to, if not indistinguishable from, the Eastern Peruvian race, Thraupis palmarum melanoptera (Sclater).
Saucerottia erythronota (Lesson). —With reference to this species also marked with a star, we do not find in Mr. Beebe’s list Agyrtrina fimbriata fimbriata (Gmelin), which is common in Br. Guiana, and which has been recorded from Bartica by Chubb (l. c., p. 395). This bird has sometimes been confused with Saucerottia erythronota (Cf. Salvin, Cat. Birds Br. Mus., 1892, xvi, p. 187) and has been listed from Bartica by Salvin (Ibis, 1885, p. 435) under the name Agyrtrina tobaci of which erythronota, type locality Trinidad, is a subspecies.
A longer stay at Bartica, no doubt would have augmented Mr. Beebe’s list considerably. For instance, Mr. Chubb, in his work on the birds of British Guiana, records twenty-seven species in the McConnell Collection, which are not included in Mr. Beebe’s list.
In Chapter XIII we find an account of the author’s ornithological discoveries, pertaining mostly to nests and eggs, with excellent photographic illustrations. Some of these discoveries, however, are by no means entirely new, reliable information on nests and eggs having been published in regard to at least twelve of the seventeen species discussed. Attention is called to the following records:
Chæmepelia talpacoti (Temminck and Knip). —Dalgleish (Proc. Roy. Phys. Soc. Edinburgh, 1889, x, p. 86) describes two nests, each containing two eggs, found Nov. 20, 1886, in Paraguay. Nehrkorn (Kat. Eiersamm, 1899, p. 184) lists eggs from Paraguay, 23 × 18 mm. Euler (Rev. Mus. Paulista, 1900, iv, p. 98) describes nests and eggs, 22.5 × 18 mm. Ihering (Rev. Mus. Paulista, 1900, iv, p. 282) describes nest and eggs, and says that he found a nest built upon the deserted nest of another bird, containing two eggs, 22 × 17 mm. F. P. and A. P. Penard (l. c., 1908, i, p. 340) describe habits, nests, and eggs under C. rufipennis, assuming talpacoti and rufipennis identical in Surinam, judging from specimens which had been identified for them in England as rufipennis. Apparently there is some confusion here, and the bird identified as rufipennis was probably the newly described Chæmepelia arthuri Bangs and Penard, (Bull. M. C. Z. 1917, p. 45).
Geotrygon [= Oreopelia] montana (Linné). —Eggs listed by Nehrkorn (l. c., p. 186) from Rio Grande, Mexico, and Porto Rico, brownish, 27 × 21 mm. F. P. and A. P. Penard (l. c., 1908, i, p. 347) say that the nest is very much like that of Leptoptila, placed on low branches of trees and in bushes; eggs, short-elliptical, brownish cream-color, 27 × 21.5 mm.; breeds in the Dry Season. Site, nest, and eggs, have also been described by Lawrence (Proc. U. S. N. M., 1879, i, p. 276), by Wells (Ibid., 1887, p. 625), and by Scott (Auk, 1892, ix, p. 124, quoting Taylor).
Porzana albicollis (Vieillot). —Nehrkorn (l. c., p. 202) describes eggs from Surinam, meas. 35 × 26 mm. Ihering (l. c., p. 286) describes eggs received from Iguape, meas. 35-26 × 27-28; he says that the eggs described by Euler (l. c., p. 102) undoubtedly belong to another species. F. P. and A. P. Penard (l. c., 1908, i, p. 206) describe habits, site, nest, and eggs, meas. 35 × 27 mm.
Creciscus viridis (P. L. S. Müller). —Nehrkorn (l. c., p. 203) describes eggs from “Guyana,” meas. 32 × 23 mm. F. P. and A. P. Penard (l. c., 1908, i, p. 210) describe habits, nest, and site fully; eggs two, rarely three, usually oval, pure white, almost without gloss, meas. 32 × 26 mm.; they say further that the eggs do not vary much, some having a few black-brown spots at the large end; in the nests are often found infertile and abnormal eggs.
Caprimulgus [= Nyctipolus] nigrescens Cabanis.—Nehrkorn (l. c., p. 156) lists eggs from Amazonia, meas. 23.5 × 18.5 mm. F. P. and A. P. Penard (l. c., 1910, ii, p. 78) describe eggs, one or two, barely glossy, elliptical, pale yellowish-rose, distinctly spotted and blotched with chocolate-brown and purple-gray, meas. 25 × 18.5 mm. The eggs described by Schomburgk (l. c., p. 711) must have belonged to another species.
Empidonomus varius varius (Vieillot). —Mr. Beebe (l. c., p. 225) states that “although the eggs of this species have been collected no description of the nest has been given.” We would call attention to description of a nest by Ihering (Rev. Mus. Paulista, 1914, ix, p. 443 and p. 482); the nest was collected by Garbe near Joazeiro, Bahia, in November, 1913.
Pipra aureola aureola (Linné). —F. P. and A. P. Penard (l. c., 1910, ii, p. 188) describe site and nest fully, giving measurements; the eggs are described as two, dull brownish gray, with numerous dark-brown spots, streaks, and dots, over the entire surface, but usually, on one of the eggs of a clutch, forming a wreath at the middle; meas. 21 × 15.5 mm.
Cyanerpes cyaneus cyaneus (Linné). —F. P. and A. P. Penard (l. c., 1910, ii, p. 475) say that the nests and eggs, 20 × 14 mm., do not differ much from those of C. cærulea, under which name they give full descriptions of nests and eggs. The eggs are described as two in number, oval, almost without gloss, black or purplish black-brown. The nest is described as made of little black roots, pear-shaped or shoe-shaped, with entrance low down at the side, measuring 16 cm. high and 9 cm. across, suspended like the nest of Todirostrum from twigs two to five feet from ground. J. A. Allen (Bull. Am. Mus. Nat. Hist., 1891, iii, p. 348) under the name Arbelorhina cyanea describes an egg collected by H. H. Smith, “taken with parents, Oct. 13, 1882,” in Matto Grosso, Brazil, but judging from the description, it must have belonged to some other species.
Under the general heading of “Seed eaters” Mr. Beebe (l. c., p. 237), speaking of Oryzoborus angolensis brevirostris, Oryzoborus crassirostris, and Sporophila castaneiventris, says, “Familiarity breeds contempt. There could be no truer saying than where these little finches were concerned. In spite of diligent search through all the few reports and excerpts on the subject, no description of the home or eggs of these birds could be found, and yet, in April and May, their nests were everywhere.” H. Lloyd Price, in his paper on “The Nests and Eggs of some common Guiana Birds” (Timehri, 1891, p. 64), says in a general way, “Various species of small finches or grass birds (Spermophila, etc.), build tiny nests in the long grass growing at the sides of the trenches; they are generally made of dry grass, and occasionally of dry sticks. The eggs, two in number, are of a grayish white spotted with either red, brown or grey, and of various sizes.” Much more definite information in regard to the breeding habits, nests, and eggs of the seed-eaters will be found in the works of F. P. and A. P. Penard, Ihering, Euler, and Nehrkorn. We would call attention to the following accounts pertaining to the species mentioned by Mr. Beebe:
Oryzoborus angolensis brevirostris Berlepsch. —Nehrkorn (l. c., p. 105) describes eggs from Brazil. Ihering (Rev. Mus. Paulista, 1900, iv, p. 213) describes nest and eggs. F. P. and A. P. Penard (l. c., 1910, ii, p. 388) says that the nest is smaller than that of O. crassirostris; the eggs are fully described. All these authors deal with this species under the name O. torridus.
Sporophila castaneiventris Cabanis. —Nehrkorn (l. c., p. 105) describes eggs from Amazonia. F. P. and A. P. Penard (l. c., 1910, ii, p. 389) describe habits, nest, and eggs fully. They add the following interesting remarks (translated): “The examples vary very much in form and color as well as in measurements. In many the markings form a distinct wreath about the larger end, others being uniformly covered with gray-brown or brown. Those with wreathed ends are usually of a more oval shape than the evenly covered eggs, but both types are often found together in the same nest. It is thought [by the natives] that the more pointed egg hatches the male, and the browner egg the female. Eggs of a more spherical shape are less common with this species than with the next [S. minuta].”
Oryzoborus crassirostris crassirostris (Gmelin). —F. P. and A. P. Penard (l. c., 1910, ii, p. 387) describe habits, nest, and eggs fully, with similar remarks in regard to variations in shape and coloration of eggs, both types sometimes being found in the same nest.
Sporophila bouvronides (Lesson). F. P. and A. P. Penard (l. c., 1910, ii, p. 392, sub nom. S. ocellata) compare nest to that of S. minuta, and eggs with those of S. castaneiventris, but say that the eggs of this species average a little longer and also a little grayer, with remarks in regard to the two types of eggs.
In another chapter the author gives much interesting information regarding the habits of Tinamous. By an ingenious experiment he is led to the discovery that birds of the genus Tinamus sleep at night in trees, while those of the genus Crypturus always pass the night upon the ground. He accordingly correlates this difference in habits to the character of the back of the tarsus, which in Tinamus is rough, and in Crypturus quite smooth. He goes on to say (l. c., p. 255):
“These two distinctions have been recognized for many years—Tinamus for more than one hundred and thirty, and Crypturus for a hundred and six years, and during all this time ornithologists have accepted this character without thought or question.”
I may say that the roosting habits of Tinamous are well known to hunters in Surinam, and according to Mr. Beebe himself they were not unknown to his Akawai hunter, Nupee, in whose statements, however, Mr. Beebe seemed disposed to place less confidence than in his own experiment, notwithstanding the fact that in either case conclusive evidence could only be sought in actual observation in the field.
Nearly one hundred years ago Charles Waterton (Wanderings in South America, 1825, p. 286) called attention to these habits and suggested that the state of the tarsus might have some bearing upon them. These are his words:
“There is something remarkable in the great Tinamou, which I suspect has hitherto escaped notice. It invariably roosts in trees; but the feet are so very small in proportion to the body of this bulky bird, that they can be of no use to it in grasping the branch; and, moreover, the hind toe is so short, that it does not touch the ground when the bird is walking. The back part of the leg, just below the knee, is quite flat, and somewhat concave. On it are strong pointed scales, which are very rough, and catch your finger as you move it along from the knee to the toe. Now, by means of these scales, and the particular flatness of that part of the leg, the bird is enabled to sleep in safety upon the branch of a tree.”
In regard to the “small Tinamou,” Waterton (Ibid., p. 287) says, “The foot of this bird is very small in proportion, but the back part of the leg bears no resemblance to that of the larger Tinamou; hence one might conclude that it sleeps on the ground.”
Here then, we have at least one naturalist to whom “the casual, nominal affair between Hermann and Illiger versus Tinamus and Crypturus” was not all.
But Waterton was not the only writer who has mentioned these things. Schomburgk, (l. c., p. 749) under the name Trachypelmus subcristatus [= Tinamus major (Gmel.)], speaks of the relation of the rough tarsus to the bird’s habit of roosting in trees, but under Crypturus variegatus (Wagler) (Ibid., p. 748) says that he does not know whether that species also passes the night in trees. More recently F. P. and A. P. Penard, under the names Tinamus subcristatus (l. c. 1908, i, p. 318) and Crypturus variegatus (Ibid., p. 322) definitely state the bearing of the construction of the tarsi in these two genera upon the dissimilarity in roosting habits.
Mr. Beebe’s discoveries in regard to the homes of Toucans, also, are extremely interesting, although the state of affairs regarding our knowledge of the life history of Toucans was really not so scanty as conveyed by the few words of Levaillant which the author quotes. It may be of interest to call attention here to a Toucan egg said to be of Ramphastos ariel Vigors, collected by Krone at Iguape, and recorded by Ihering (Rev. Mus. Paulista, 1900, iv, p. 262). It is described as oval, measuring 37 × 28 mm., white, with deep pits on the surface. Schomburgk, Burmeister, and others from time to time, have mentioned Toucan eggs, but beyond saying that the eggs were white, two in number, laid in holes in trees, they did not give much information.
In concluding I wish to emphasize that I appreciate fully Mr. Beebe’s good work at the research station in British Guiana, and my remarks should not be construed as having been made with the purpose of depreciating the excellent publication, of which I have discussed, after all, only some very unimportant details.
PROBLEMS SUGGESTED BY NESTS OF WARBLERS
OF THE GENUS DENDROICA.
BY JOHN TREADWELL NICHOLS.
The genus Dendroica with center of abundance in eastern North America, containing numerous closely related birds, inhabiting in a general way the same region and boldly contrasted the one from the other in plumage, constitutes a striking natural phenomenon calling for explanation.[18]
First what advantage to the race can there be in the evolution of so many species of similar habits? Probably though in the main not unlike, a careful comparative study of the species will show that sufficient difference of habit accompanies each to make it fit a slightly different niche in the environment. I mention a single phase, the construction of the nest. For my data on warbler nests I am indebted to Mr. P. B. Philipp of New York, who possesses a very complete personally collected series of these. In his collection we have together verified interesting points that he has learned, and also worked out other matters.
The nests of different species of Dendroica, even when found in the same country, are remarkably distinct and can usually be recognized at a glance. In Northumberland County, New Brunswick, a locality with which Mr. Philipp is particularly familiar, Cape May, Yellow, Black-throated Blue, Myrtle, Magnolia, Baybreasted, Blackpoll, Blackburnian, Black-throated Green, and Yellow Palm Warblers all breed, and he has found the nests of all but the Blackburnian placed in spruces at different heights. The nest of the Blackburnian has not been found here, but doubtless is placed high up in the spruces, as he has found it in such situations in Pennsylvania. The Yellow Palm Warbler usually nests on the ground in moss or dead ferns, but one nest was placed a few inches from the ground in a small spruce. Though a single nest of the Yellow Warbler was found in a spruce, that species may nest more commonly in the willows. Cape May, Myrtle, and Blackburnian Warblers nest high, the other species low.
The nest of the Black-throated Blue has a characteristically pale exterior, weed stems, pale bark, and rotten wood-chips being favorite materials for the bird to use in its construction. It is lined with black, hair-like, slightly crinkly substance, much used for that purpose by Warblers, the stem of a woodland ground-moss (the Cape May has been seen gathering this material). Occasionally horse-hair is substituted for it. In the Black-throated Green, spruce twigs and birch-bark whorls are characteristic of the exterior; hair and an occasional feather, of the interior. The Myrtle and Blackpoll both line the nest heavily with feathers; but the exterior is very different in the two,—in the Myrtle compact, of spruce twigs and fine dry grass, in the Blackpoll loose and bulky, rotten wood-chips, mosses, and a few twigs being used. The Magnolia lines its nest with horse-hair if it can get it, this material being present in Pennsylvania nests taken where it was obtainable, but will use other hair or “moss-stems.” One half or more of Mr. Phillipp’s nests are lined with horse-hair. The Magnolia’s nest is composed outside entirely or almost entirely of spruce twigs or grass and is a ragged looking nest. The Baybreast builds a ragged nest that looks like that of the Magnolia but is much larger; for lining it uses fine roots or “moss-stems.” The Cape May’s nest is thick-walled, rather flat, with fine sticks, a little grass and characteristic dried green moss on the outside, feathers and usually light colored hairs neatly molded down inside. A few “moss-stems” are used in construction, and outside, here and there are specks of very adhesive down. Mr. Phillipp has seen a Cape May gathering fur from a dead rabbit, and also apparently picking hair out of a brush-pile.
As regards other species, the Blackburnian builds a nest resembling the Magnolia’s but more compact and placed higher. The nest of the Yellow Warbler is smooth, very pale, of plant-down without, and fern-down within. The Yellow Palm Warbler’s nest, usually placed on the ground in moss at the foot of a small spruce, is bulky, fairly thick-walled, of grass lined with fine rootlets often combined with some porcupine and at times other hair, and with usually only a few feathers.
There is some variation in the typical location of the nests by species, and in general the nest is very inconspicuous in its location. The dried moss on the Cape May’s nest may be especially adapted to conceal it (from below) in the spruce tops from its enemy, the Red-Squirrel. The Baybreasts’ ragged nest, well out on a low limb, is almost transparent. The pale Black-throated Blue nest in New Brunswick spruces is placed close to the trunk where it is well concealed; nesting in the rhododendrons in Pennsylvania, the Black-throated Blue nest is well concealed by the glint of light on the rhododendron leaves.
The nest of a bird is one of the most notable products of its instinct. Obviously much precision is necessary in selecting the appropriate materials and fitting them together, for the attainment of a successful product. That to obtain the right materials is a problem to the individual bird is evidenced by the adoption of horse-hair by the Magnolia Warbler to supplant the very similar “moss-stems” which doubtless were its original material. The Chipping Sparrow must have substituted horse-hair for some pre-civilization material, and its habits are such that horse-hair is almost always obtainable by it and now almost the invariable nest-lining for the species. It is clear that to be successful the nest-building instinct of a given species must be pretty well fixed, that a bird must know what material it will use, also were all the Dendroicas dependent on,—let us say, feathers, horse-hair, or rabbit fur, there would be less of it for each, and specific differentiation is thus an advantage to the Dendroicine population as a whole.
Secondly, what advantage to the species is there in their contrasted plumages—in the writer’s opinion the colors of each act as a uniform, facilitating the recognition by a bird of its own kind just as they facilitate its recognition by a bird student.[19]
A varicolored group of animals such as Dendroica, where many related species occupy the same locality,—other such groups come to the writer’s mind, notably among tropical reef fishes,—should be considered in formulating or accepting theories on species formation. In many cases isolation and reinvasion are doubtless the succeeding steps in speciation, a process clearly indicated by work recently done by Taylor on the mammals of California.[20] There is no inherent impossibility of the many Dendroicas of eastern North America having been similarly evolved, but with them it would seem to have been a difficult and complicated process instead of a simple and easy one, as with sedentary mammals in a broken country, and may not the forms have arisen for biological advantage without these steps?