(2191) Fregata andrewsi.
The Christmas Island Frigate-bird.
Fregata andrewsi Mathews, Austral Av. Record, ii, p. 110 (1914) Christmas Is.). Fregata artel Blanf. & Oates, iv, p. 338.
Vernacular names. None recorded.
Description. - Male. Whole plumage black, the feathers of the head, back and mantle very long, lanceolate and strongly glossed with metallic green ; anterior abdomen and flanks white; lesser wing-coverts edged with pale brown.
Colours of soft parts. Iris red; bill bluish-grey; gular skin, legs and feet red.
Measurements. culmen 127 to 180 mm.; wing 600 to 625 mm.; tail 375 to 400 mm.; middle toe 54 to 60 mm.; culmen 137 to 145 mm.; wing 635 to 643 mm.; tail 430 to 450 mm.; middle toe 60 mm.
Female differs from the male only in having the breast, abdomen and flanks pure white. Judging from the sexed specimens in the British Museum the wings of males and females have the measurements alike.
Young birds have the upper parts blackish, the centre of the back duller brown ; the feathers are short and rounded and have no gloss; the whole head, neck and breast are white, much suffused with rufous; there is a broad band of brown below the breast; abdomen white; vent, thigh-coverts and under tail-coverts black.
Distribution. Indian Ocean; breeding on Christmas Island, whilst immature specimens have been obtained on Assamba Island and Cocos Keeling Island.
Nidification. The Christmas Island Frigate-bird breeds in large colonies, making a rough nest of sticks and weeds, which it places either actually on the ground, or within a few inches of it in the scrubby growth on the shores above high-water mark. The eggs number one or two and are all pure white, in shape like those of the Gannet but without any chalky covering and decidedly more fragile. They measure about 70.4 x 50.4 mm. but a larger series than mine would probably give much smaller measurements.
The breeding-season seems to be April.
The birds sit very close and snap at anyone disturbing them but do not eject fluid in the unpleasant way the Petrels do.
Habits. Frigate-birds in their manner of feeding resemble the Skuas, bullying Gulls and Terns and making them give up freshly-caught fish and disgorge those they have swallowed, catching the rejected article before it has time to fall into the sea. At other times they evidently feed themselves, as their stomachs have been found to contain the remains of crabs, Crustacea of other kinds arid certain food on which their victims do not normally feed. Their power of flight is wonderful and it is but seldom they are seen to rest on land or sea. though, of course, they are fine swimmers when necessary. Their ordinary call is a loud, fierce croak.