NON-INDIGENOUS BRITISH BIRDS. 287 



Family LARID.-E. Genus Larus. 



Sub-family LARIN^:. 



ICELAND GULL. 



Larus leucopterus, Faber. 



(British : Rare nomadic autumn and winter migrant.) 



Single Brooded. Laying season, June and early July, 



Breeding area : Northern Nearctic region. The 

 Iceland Gull is only known to breed in Greenland, and 

 probably across Arctic America to Alaska and the 

 Aleutian Islands. 



Breeding habits : The Iceland Gull is another 

 species that wanders but a short distance south of open 

 water during winter, and retires to its breeding haunts 

 as soon as the adjoining seas are free from ice. This 

 Gull breeds more or less in colonies, and its favourite 

 nesting places are either the lofty cliffs above the Arctic 

 Ocean or the sandy beaches at the mouths of rivers that 

 fall into that sea ; in some districts small islands appear 

 to be preferred. Of the pairing habits of this Gull I 

 find nothing recorded. The only nests of this species 

 that appear to have been described are those found by 

 Dall on the banks of the Yukon in Alaska. These were 

 merely shallow hollows in the sand. 



Range of egg colouration and measurement : 

 The eggs of the Iceland Gull are two or three in 

 number. They vary in ground colour from pale grayish- 

 buff to dark buff and olive, blotched and spotted with 

 dark brown and pale brown, and with underlying 

 markings of lilac-gray. The markings are seldom large, 

 and either uniformly distributed over the surface of the 

 ^<g^ or mostly confined to the major half, where they 

 not unfrequcntly form a zone. The gray underlying 



