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.
"More mature birds (? plumage of the second year).--Breast, belly,
and under parts largely mixed with white, only the subterminal portion
of each feather smoky brown.
"Still more mature bird (? plumage of the third year).--Head, neck,
chest, and upper parts darker brown, and more like those of the adult;
the breast and belly thickly mixed with the pure white feathers of the
adult. These appear to be entirely attained by molt, many half-grown
ones being concealed beneath the plumage." (Grant.)
This gannet is quite abundant about the small islands north of Luzon
and it probably finds nesting places on some of the more isolated
rocks. Gannets lay their chalky white eggs in the sand or construct
flat nests of sticks which they place in bushes or trees. One or two
eggs are deposited in a nest.
Family FREGATIDÆ.
Bill long and strongly hooked, both mandibles decurved at tip; lateral
grooves deep; nostrils situated in the grooves and practically closed;
a large naked and brightly colored gular pouch; wings pointed and
extremely long; first primary longest; tail long and very deeply
forked; feet absurdly small and weak for so large a bird; claw of
middle toe pectinate; tarsus very short; plumage black with beautiful
green and purple gloss.
Genus FREGATA Lacépède, 1799.
Characters same as those given for the Family.
Species.
a1. Breast and sides black (males).
b1. Larger; culmen, 92 to 112 mm.; wing, 520 to 655; no white patch
on flank. ... aquila (p. 206)
b2. Smaller; culmen, 58 to 89 mm.; wing, 488 to 533; a white patch
on each flank. ... ariel (p. 207)
a2. Breast and sides white (females).
b1. Larger; culmen, 109 to 132 mm.; wing, 612 to 678; no white
collar round back of neck. ... aquila (p. 206)
b2. Smaller; culmen, 81 to 91 mm.; wing, 510 to 528; a white collar
round back of neck. ... ariel (p. 207)