LIFE HISTORIES OF NORTH AMERICAN PETRELS AND PELICANS. 311 



molt, when the birds are a little over two years old, the adult plum- 

 ages of the male and female are assumed. The plumage of the male 

 is then entirely black, with its beautiful metallic luster and lanceolate 

 feathers on the upper parts ; and the flight feathers have reached their 

 fullest development; the bright red gular sac of the male is an 

 adornment of the nuptial season only. The female in full plumage 

 has the head and neck clear blackish brown and the breast and sides 

 pure white ; she is less glossy above than the male, there is more or 

 less brownish in the wing-coverts, and the feathers of the upper parts 

 are less lanceolate. 



Food. — The food of the man-o'-war bird consists largely of fish, 

 but it includes much of the varied bills of fare indulged in by the 

 various species of boobies, pelicans, cormorants, gulls, and terns on 

 which it makes its piratical raids. It is not wholly predatory in its 

 feeding habits and obtains much of its food by its own efforts from 

 the surface of the sea at which it is very skillful. Doctor Fisher 

 (1904Z>) says: 



Frigate birds glean a portion of their livelihood from the host of creatures 

 which live at the surface of the ocean — flying fishes, ctenophores, jelly fishes, 

 vellela, janthina, and in fact anything that may attract their fancy. I even 

 observed one bird aimlessly carrying a splinter of wood, uncertain of itg 

 utility, yet imwilling to release it. As they never alight on tlie water they 

 seize such bits of food by swooping down in a broad curve. They are able to 

 measure distance so accurately that no disturbance is created when the object 

 is grasped. 



Prof. William A. Bryan (1903) has given us an excellent account 

 of the frigate bird's attacks on the boobies of Marcus Island, as 

 follows : 



I have before referred to the large colonies of common brown boobies about 

 the north point of the island. It was in the vicinity of this colony that the 

 man-o'-war birds were most abundant. Here they would lie in ambush for the 

 old boobies and tropic birds as they returned from the sea heavily laden with 

 fresh food for their yoimg. Sitting quietly on the tree tops, or more often 

 wheeling high overhead industriously patrolling the island, out where the surf 

 broke on the reef, these birds would keep a sharp lookout to sea for a sight of 

 the returning fishing fleet of boobies. Sighting one (sometimes consisting of 

 one, sometimes of several individuals), as many as half a dozen hawks would 

 make for them under full sail, and without a moment's warning would engage 

 a helpless bird in battle. Swooping down upon it from every side, buffeting it 

 with their wings, snapping at it with their long hooked bills, flying now above, 

 now before, now below it, the hawks would so confuse their victims that 

 eventually, feeling that the only safety for its life lay in letting go part of its 

 store of supplies as a sop for its assailants to quarrel over, the booby would on 

 a sudden drop one of its fish, w^hereat a hawk would swoop down, more rapidly 

 than the eye could follow, and catch the food before it had touched the wave, 

 then taking it securely in its bill would fly majestically off to feed its own ever- 

 expectant offspring. The unfortunate booby meanwhile was farther pursued 

 by the less fortunate hawks until, reft of her quarry, she was allowed to 

 return to her young. 



