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 Farde 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 
