64 BULLETIN 115, UNITED STATES NATIONAL MUSEUM. 



Food. — The feeding habits of the Iceland gull are similar to those 

 of the glaucous and herring gulls. They are ever on the alert to pick 

 up dead fish, Crustacea, or other edible substance from the surface 

 of the water and from the beaches. About Eskimo encampments 

 seal and fish refuse are eagerly sought. Hagerup (1891) states that 

 in Greenland the young feed on the berries of Empetrum nigrum* 

 He also says: 



For a while after leaving the nests they are accompanied by one of the 

 parents, or by both, and these give warning in a wise and unmistakable manner ; 

 " Don't go near those treacherous boats," they seem to cry. Later on the young 

 mingle with the young of the glaucous gull, but not with young kittlwakes. In 

 voice and habits the young birds quite resemble young glaucous gulls. 



Behavior. — Like other gulls and terns the Iceland gull is some- 

 times of value to man in indicating the presence of fish. Baird^ 

 Brewer, and Ridgway (1884) quote from Faber a statement that in 

 1821 " on the 1st of March the shore was full of sea gulls ; but early 

 on the 2d the air was filled with numbers of this species which had 

 arrived during the night. The Icelanders concluded from the sud- 

 den appearance of the birds that shoals of codfish must have arrived 

 on the coast, and it was soon found that this conjecture was correct." 

 He adds that these gulls " would indicate to the seal shooters in the 

 fiord where the seals were to be looked for, by following their track 

 to the sea and hovering over them in flocks with incessant cries." 

 In both cases it is probable that the larger creatures stirred up the 

 water so that the smaller food of the gulls could be obtained. In 

 the same way flocks of terns follow whales, not with any expecta- 

 tions of feeding on the whale, but on the smaller marine life stirred 

 up by the whale and on which both feed. 



Winter. — Iceland gulls, as well as glaucous and Kumlien gulls, 

 visit the New England seacoast more in some than in other winters, 

 dependent, no doubt, on the amount of open water and on the suffi- 

 cient or insufficient food supply in the north. In the winter of 1907 

 and 1908 we were favored with an unusually large number of these 

 northern birds in the vicinity of Boston. F. H. Allen (1908) re- 

 ported one or two Iceland gulls in immature plumage in Charles 

 River Basin and in Boston Harbor, at least three at Swampscott, 

 and one at Lynn and Marblehead. 



DISTRIBUTION. 



Breeding range. — Portions of the Arctic regions; from Victoria 

 Land (Cambridge Bay), Boothia Peninsula, and west-central Green- 

 land east probably to Nova Zembla ; southern limits not well defined. 

 Said to breed in Hudson Bay. Mackenzie Bay and other western 

 records are not well established and should be discredited. 



