"Immature in first plumage.--Entire plumage above and below brown, lighter on breast and belly; primaries and secondaries and their coverts like those of the adult, but the inner webs of the secondaries black. Cutting edges of the mandible sometimes serrated, and the inner margin of the middle claw pectinate. Bill bluish pink, the latter predominating toward the base; naked skin round eye dark leaden hue; gular pouch flesh-colored. "More adult specimens (perhaps in the plumage of the second year) head, neck, and under parts white; back, wings, and tail brown as in the immature; middle tail-feathers dark, brownish gray toward the base, shading into white toward the extremity. "A still more adult bird has a large amount of white or partially white feathers mixed with the brown of the back and wings. "I should imagine that the fully adult plumage is not attained until the third or perhaps the fourth year. This species may be recognized in all stages of plumage by the hoary gray appearance on the outer webs of the quills." (Grant.) 169. SULA LEUCOGASTRA (Boddaert). BROWN BOOBY. Pelecanus leucogaster Boddaert, Tabl. Pl. Enl. (1783), 57. Sula sula Grant, Cat. Birds Brit. Mus. (1898), 26, 436; Sharpe, Hand-List (1899), 1, 237; McGregor and Worcester, Hand-List (1906), 40; Oates, Cat. Birds' Eggs (1902), 2, 212; Worcester, Phil. Jour. Sci. (1907), 2, sec. A, 275. pl. 1 (Didicas Rocks). Sula leucogaster Blanford, Fauna Brit. Ind. Bds. (1898), 4, 346, fig. 80 (head). Sula leucogastra A. O. U. Committee, Auk (1908), 25, 359. Batan (McGregor); Calayan (McGregor); Didicas Rocks (Worcester); Dinagat (Everett); Luzon (McGregor); Mindanao (Cuming, Everett). Tropical Atlantic, Indian, Australian, and Pacific Oceans. "Adult.--Head, neck, chest, entire upper parts, wings, and tail dark sooty brown; breast, rest of the under parts, axillars and under wing-coverts of the secondaries pure white. Tail composed of 14 feathers. Iris silvery white, white, or gray; bill whitish green or greenish blue, becoming flesh-colored or bluish at the base; naked skin on sides of face and gular pouch bluish, greenish, or yellowish; legs and feet pale green or lead-green, sometimes inclining to yellowish. "Adult male.--Length, about 711; culmen from feathers on forehead, 100; wing, 389 to 396; tail, 190 to 195; tarsus, 46 to 48. "Adult female.--Length, about 711; culmen from feathers on forehead, 100; wing, 389 to 396; tail, 190 to 195; tarsus, 46 to 48. "Immature in first plumage.--Differs in having the head, neck, chest, entire upper parts, wings and tail brown, much lighter than in the adult; breast, belly, and under parts still paler brown, the feathers fringed with whitish brown, and generally sharply defined from the darker chest; axillars and secondary under wing-coverts mixed with smoky brown.