38 



A peculiar bird, half raptorial, half web-footed, also inhabits 

 the mountain plateaux, especially where they alternate with 

 marshes, and draws attention to itself by its odd habits. This 

 is the Buffon's Skua (Stercovarius parasiticus), which unlike its 

 relative in the belt of islands girding the coast, only makes its 

 appearance in a single plumage with' white abdomen, a black- 

 bellied phase being unknown. With a curious cry it approaches 

 the hunter, flaps about him in large circles, now and again 

 remains motionless in the air, exactly like a Kestrel, and at last 

 settles down upon a tussock to wait until the danger has passed 

 away. Its food is as varied as that of its relative, and especially 

 in the years in which the Lemmings undertake their mass 

 wanderings, it lives largely upon them and various species of 

 Arvicola, whilst it ordinarily persecutes young birds, and in times 

 of scarcity contents itself with berries and insects. 



Though animal life under ordinary circumstances seems to be 

 sparse upon these extensive wastes, it is otherwise in the years 

 in which, as above mentioned, the Lemming (Myodes lemmus) 

 multiplies beyond its normal number, and undertakes its emigra- 

 tions. This renowned little rodent, with its handsome yellow 

 and black pied skin and its hasty temper, lives as a rule a 

 little-noticed life among the tussocks and the willow-scrub upon 

 the high mountains, and as an essentially nocturnal animal one 

 sees under ordinary circumstances little or nothing of it. 



But in certain years, under conditions which are inexplicable 

 to us, there comes to pass their multiplication in an inordinate 

 degree, for their prolificness during these years is almost 

 incredible. Litter follows litter the whole summer through ; 

 young ones, which first saw the light in the spring, are already 

 breeding in the autumn, and the old individuals often produce a 

 new litter of young in the same nest, which the half-grown young 

 of the preceding litter have not yet left. Gradually, as they 

 over-run their native place, they set out upon their wanderings 

 over the sides of the mountain ; and in these great " Lemming- 

 years " they are therefore common everywhere, alike upon the 

 mountains and in the valleys, and by degrees reach far down 

 upon the lowlands, where they are otherwise entirely unknown. 

 They are now in motion at all hours of the day, they cross rivers 



