70 BUIiETIN 113, UNITED STATES NATIONAL MUSEUM. 



molt. I do not think that primaries with the apical white spots of the adult 

 bird are ever developed until a year later, but in some birds there is a fore- 

 shadowing of the white spots on the first primary. The third winter plumage, 

 that of the adult, is the result of the second post-nuptial molt, after which 

 very few birds can be found, showing traces of immaturity. The new primaries 

 are slaty, and white tipped, the first and sometimes the second with subapical 

 or sometimes terminal white " mirrors," quite unlike the unpatterned feathers 

 of glwucus or the smaller leucopterus. The mantle varies from cinereous to 

 plumbeous gray, the color running over into the primaries, which become de- 

 cidedly slaty toward their apices. The white of the head and neck is still 

 clouded, the dusky markings being characteristic of winter plumages until the 

 birds are quite advanced in age. At prenuptial molts, as in the other species, 

 these feathers are replaced by white ones. 



Food. — These, like other large gulls, are useful scavengers all along 

 the coast and are practically omnivorous. They were constantly fol- 

 lowing our ship in search of small scraps that might be picked up, 

 and, while we were at anchor at Ketchikan and Unalaska, they were 

 especially numerous and always in sight, eagerly waiting for the 

 garbage to be thrown overboard. They are abundant, in winter, in 

 the harbors of nearly all the large cities on the Pacific coast as far 

 south as southern California, where they feed largely on refuse and 

 seem to fill the place occupied by the herring gull on the Atlantic coast. 

 They are particularly numerous about the garbage heaps which are 

 dumped on the shore to be washed away by the advancing tides. In 

 such places they appear to realize that they are protected and are 

 very tame. In their eagerness to secure the choice morsels of food 

 they seem to forget all about the presence of human beings, even 

 within a few feet. At other times it is difficult for a man to walk 

 up within gunshot distance of them. They become much excited 

 and clamorous in their scramble for food, competing at close quar- 

 ters with other species of gulls, with dogs, and with the lazy Indians. 

 They are none too particular in their choice of food and will eat 

 almost anything that is edible. 



During the summer they frequent the vicinity of the salmon can- 

 neries, where they gorge themselves on the refuse from the factories 

 or fishing vessels and on the bodies of dead salmon along the shores. 

 As a result they become very fat. On the Pribilof Islands they 

 regularly visit the killing grounds to feast on the entrails and other 

 waste portions of the slaughtered seals, which furnish an abundant 

 food supply. Among the Aleutian Islands, where sea urchins are 

 abundant, we found numerous broken shells of these creatures on the 

 rocky heights frequented by the gulls. Evidently they had been 

 dropped on the rocks to break the shells. In the colonies, where they 

 were nesting with other species, we saw no evidence to prove that they 

 feed on the eggs or young of their neighbors, though they may, 

 perhaps, do so occasionally. On Walrus Island we kept some of the 



