8o The Alps in J\ 



line. 



Black Redstart, the Citril Finch, and some of the 

 hardier warblers, seem to desire a cool climate to 

 breed in, and doubtless come across the passes to 

 inhabit the Alpine pastures during the whole of 

 the summer. How far this is also the case with 

 the vast number of more delicate birds, such as 

 the various Reed- and Willow-warblers, who live 

 by the rivers and lakes during the summer, I 

 'cannot undertake to say ; and it is a mere guess 

 on my part if I hazard an opinion that many of 

 these must come into Switzerland by way of 

 France and Austria. Ancleregg sent me word 

 last autumn that he had noticed the Swallows 

 leaving Meiringen, not southwards over the 

 Grimsel pass towards Italy, but westwards, as if 

 they were seeking to turn the vast mountain 

 barrier. Yet it is a known fact that on some of 

 the passes birds are watched and killed in their 

 passage. 



But I have still to speak of partial or internal 

 migration in Switzerland ; and this is what, if I 

 am not mistaken, will prove a very fertile source 

 of ornithological knowledge when thoroughly 

 understood. As I said before, the agents which 



