_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