The Avifauna of Micronesia, Its Origin, Evolution, and Distribution

by Rollin H. Baker

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).