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).