BULLETIN OF THE UNITED STATES FISH COMMISSION. 
798 
At French Frigate Shoals we saw a number of them, and on Necker Island the species breeds but 
is not at all abundant. The two eggs are laid on a level place, where there happens to be a little soil, 
upon a shelf of the rock. We also found rather large young in white down, and all intergradations 
between these and the egg. Frequently both birds sit by the nest, and they did not appear particu- 
larly suspicious. As in the case of Sulci cyanops, only one young appears to be reared, although two 
eggs are laid. Of those eggs collected one of a set was fresh and the other much incubated. The eggs 
are either ovate or elliptical ovate and an average specimen measures 58 by 40 millimeters. 
Sula sula breeds on Bird Island, and prefers the brink of the escarpment of rock on the south 
side. In August we saw numbers of young birds, wholly brown. 
FREGATID^. 
Freg-ata aquila. Man-6’ -war Bird. 
Pelecanus aquilus Linn., Syst. Nat., ed. 10, I, 1758, p. 133. 
The man-o’-war bird proved scarcely less entertaining than the albatrosses. The curious and 
excessively bizarre appearance of the male at this season of the year compels attention. His antics 
are as extraordinary as his looks, and when engrossed in the task of making himself attractive his 
self-absorption and apparent vanity are highly diverting. During the courting period the gular pouch 
of the male is enlarged, and before the brooding cares have begun he inflates it to a large size, and at 
the same time it becomes a bright red color. The bird looks as if there were a balloon, such as children 
dangle on a string, fastened to its throat. 
The pouch is apparently a large air-sac, connected only indirectly with the lungs, which can not 
be emptied readily nor inflated instantly. It varies in the intensity of its carmine or crimson, and 
catching on its surface the sheen of the sky, shows at times bluish hues, or, becoming somewhat 
collapsed, turns a translucent orange about the sides. It is no uncommon occurrence to see a male bird 
sitting on the nest with the sac blown out, obscuring the whole front of the creature, only the bill and 
eyes appearing over the top. For hours he sits on a newly-made nest without once leaving or scarcely 
altering this position. But if the female appears somewhere overhead, sailing to and fro, he suddenly 
arouses himself from the lethargy, and as she passes he rises partially from a sitting posture, throws 
back his head, spreads his wings, and protruding the brilliant pouch, shakes his head from side to 
side, uttering a hoarse cackle. Occasionally, when the female alights near, he waves his pouch from 
side to side, the head being thrown well back and the wings partially spread. At the same time 
the long, greenish, iridescent, scapular feathers are fluffed up and the creature presents a most unusual 
and absurd appearance. In this posture he chuckles again and again, and rubs his pouch against his 
mate, who usually ignores him completely and flies away. These performances take place before the 
egg is laid; afterwards, the male ceases to inflate his sac. (Figs. 39, 40.) 
At Laysan the birds live in colonies, varying from a few pairs to many, and the nests are always 
built on the tops of low bushes, sometimes very. close together. The species has congregated almost 
entirely on the eastern half of the island, and their villages are spread over the inner slope of the old 
atoll basin. The nests, which are sometimes so old that they have become mere masses of filth, are 
scarcely more Than platforms of sticks, not entirely devoid of leaves, woven together loosely with 
morning-glory ( Ipomcea ; insularis) vines. There is <• one pure white glossless egg, and we observed a 
very few newly hatched, almost naked, young. The eggs do not vary nearly so much as those of 
Sula, either in size or shape. A rather blunt ovate is the usual contour, though some are elliptical 
ovate and others approach short ovate. A fairly average specimen measures 72 by 50 millimeters. 
In some of the eggs the limy outer coating is piade, apparent by the egg having been scratched when 
newly laid; but the inner layer is white, not pale blue as in Sula. 
Both parents take turns in covering the egg, which is a necessity, for if the nest were left without 
an occupant other frigate birds would quickly appropriate its material, especially if the nest were new. 
Consequently, even before the egg is laid, either bird holds down the property, as it were, against 
marauding neighbors. After the nestling is out this vigilance is all the more necessary, for if left 
unprotected a young bird would very likely serve as food for some watchful reprobate of the vicinity. 
Mr. Snyder saw an old frigate bird snatch up and fly away with a young of the same species, whose 
parent had been frightened off the nest. According to Henry Palmer « who visited the island a few 
a Avifauna of 
