126 BRITISH SEA BIRDS. 



web-footed birds, with no hind toe, with the 

 legs placed far back, and the bill subject to 

 great variation in size, and in some species 

 presenting considerable change in appearance 

 according to season. All the Auks have com- 

 paratively short and narrow wings ; in the recently 

 extinct Great Auk these were incapable of support- 

 ing the bird in the air ; and the tail is remarkably 

 short, in some species being scarcely perceptible 

 under ordinary circumstances. The Auks are 

 exclusively confined to the north temperate and 

 polar regions of the Northern Hemisphere : and 

 by far the greater number of species inhabit 

 the Northern Pacific. They number some thirty 

 species. The prevailing colours of the Auks 

 are black and white ; none of them are showy 

 birds ; but some species are remarkable for their 

 eccentric nuptial plumes, and for the brilliancy 

 of colour of the bill. The Auks are thoroughly 

 aquatic, and not adapted in any way for a 

 terrestrial existence. They swim well, dive with 

 marvellous skill, and save during the incubation 

 period, pass most of their time on the sea. 

 None of the species are remarkable for any 

 great migration flights ; as a rule they wander 

 little from their high northern homes. They are 

 all gregarious birds, breeding in companies wherever 

 possible. Some species undergo but little change 

 in their appearance between summer or winter 

 plumage ; others are more remarkable in this 



