NOMADIC MIGRATION. 163 



shoots, and pine-needles. I have known the Red 

 Grouse make similar nomadic movements during 

 heavy snowstorms, wandering miles from the moors, 

 and even visiting farmyards and towns. Again, 

 many of the Crossbills {Loxia) are typical nomadic 

 migrants, having no regular season of passage or 

 route of flight, wandering up and down as it were 

 on the fringe of winter, now north, now south, in 

 sympathy with each recurring change. Various 

 species of Arctic Ducks (Axatid.e) and Gulls 

 (Larid^) are also good examples of this nomadic 

 migration. Many of these birds never wander 

 much south of open water during winter, unless 

 compelled to do so by violent gales, ice-floes, and 

 snowstorms. Steller's Eider (Somateria stelleri) and 

 the King Eider {Somateria spectabi/is) breed on the 

 coasts of the Arctic Ocean, and the adult birds 

 rarely come further south than where they can find 

 open water during the long Polar winter ; young 

 birds, however, as is customary, wander further 

 south, but never more than in a nomadic fashion. 

 The Ivory Gull {Fagophila eburnea), the Snow Bird 

 of the Arctic navigator, is another of the few 

 resident species in the Polar zone, and its nomadic 

 migrations are short, irregular, and uncertain. It 

 lives amongst the eternal ice, and its omnivorous 

 tastes enable it to pick up a sustenance in regions 

 where most other creatures would inevitably perish. 

 The Litde Auk {Mergidus alle) is very similar in 

 its movements. Its grand head-quarters are the 

 dreary coasts of Spitzbergen (although it breeds in 



