GULLS AND TERNS. 17 



dispersal of others is just as remarkably restricted. 

 For instance, the Glaucous Gull has a circumpolar 

 habitat, and the Black-headed Gull ranges from 

 the Faroe Islands to Japan ; but, on the other hand, 

 Larus fuliginosus is said to be peculiar to the 

 Galapagos Islands and Larus bulleri to New 

 Zealand. Three out of the four species of Arctic 

 Skuas are circumpolar in their distribution ; the 

 fourth may possibly be so. 



In adult plumage the Gulls are not remarkable 

 for any great diversity of colour. French gray 

 predominates upon the upper parts ; the under parts 

 are white, often suffused with a delicate rosy tint ; 

 the primaries are usually dark gray, brown, or 

 black, in many species spotted and tipped with 

 white. Some species assume (by a change of 

 colour and not by a moult) a sooty-brown or black 

 head or hood during the breeding season ; Ross's 

 Gull dons a black narrow collar at that period. 

 The wings are ample, long, and pointed ; the tail is 

 even, except in Ross's Gull in which it is wedge- 

 shaped, and in Sabine's Gull in which it is forked. 

 The legs are comparatively short, and the feet are 

 webbed. 



Gulls moult twice in the year. When first 

 hatched young Gulls are covered with down. 

 Young, in first plumage of the Black -headed 

 group of Gulls, have the feathers of the mantle, 

 the scapulars, and the innermost secondaries, brown 

 with pale margins ; the crown, nape, and ear-coverts 



B 



