LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 95 



are comparatively rare, it may be that these are merely backward 

 or less vigorous birds, and that normally vigorous birds acquire 

 their fully adult plumage when 3 years old. I am inclined to think 

 that this is so, but, as I am not sure of it, I have given what seem 

 to be the facts in the case. The seasonal molts of the adult consist 

 of a complete postnuptial molt in the summer and a partial molt 

 about the head and neck in the spring. In spite of statements in 

 some of the books to the contrary, adults have the heads streaked 

 with dusky in the fall, which markings disappear by wear or fading, 

 or perhaps by molt, before spring. 



Food. — Before the encroachments of civilization gave the western 

 gull an easy way of earning its living as a scavenger, its principal 

 food supply was gleaned from the sea; it followed the schools of 

 small fish in flocks, hovering, screaming, and struggling for its prey 

 in strenuous competition. When its appetite was satisfied a game of 

 tag sometimes ensued, such as Mr. J. H. Bowles (1909) described as 

 follows : 



One catches a herring, and instead of eating it flies with the fish hanging 

 from its bill, past three or four comrades. These accept the challenge and rush 

 madly after, while the pursued goes through all sorts of evolutions in seeking 

 to elude them. If overtaken, the order of chase is reversed, and the game 

 goes merrily on until all are tired. The fish, or tag trophy, is not eaten but is 

 dropped upon the playground in a condition decidedly the worse for wear. 



Although fish still form a large part of its food, especially about 

 its breeding grounds, it is primarily a scavenger, like the other 

 large gulls, and has learned to frequent harbors and populated 

 shores, where it can easily gorge itself on the garbage dumping 

 grounds, pick up unsavory morsels at the outlets of sewers, and feed 

 on whatever refuse it can find scattered along the beaches. It also 

 follows vessels to pick up whatever scraps of food are thrown over- 

 board. It feeds at low tide on the sand flats, mud banks, river 

 shores, and mussel beds, where it finds dead fish, clams, seaworms, 

 dead rats, or any kind of fresh animal food or carrion. It under- 

 stands how to break the shells of a clam or a sea urchin by flying up 

 into the air with it and dropping it on hard ground or on a rock, 

 sometimes making several attempts before succeeding. 



Mr. Walter E. Bryant (1888) says of its feeding habits: 



The gulls are indiscriminate feeders; in addition to their usual articles of 

 diet, they subsist largely upon eggs during the summer. They do not eat the 

 eggs of their own species, nor do they trouble the cormorants after the murres 

 have commenced laying. Sea-urchins, crabs, young murres, and rabbits, and 

 fish stolen from the cormorants' nests are eaten. Not being quick enough to 

 swoop upon the rabbits they catch them by patient watching at their burrows, 

 and will patiently try for 15 minutes to swallow a squealing young rabbit, and 

 finally fly away with the hind feet protruding. The dead bodies of murres are 

 also eaten; they detach pieces of flesh by backing away and dragging the 

 body, meanwhile shaking their heads, till a piece breaks off. 



