Carrion Crows. 187 



in the winter, and the white species seldom ; but 

 as to what becomes of them I am unable as yet to 

 be sure. Perhaps they simply move down the 

 river into the lower and warmer districts of western 

 and northern Switzerland ; just as in England 

 also there is a general movement of Wagtails 

 in the autumn from the more mountainous dis- 

 tricts into the regions of plain and meadow. 



Another unusual sight was the vast assembly of 

 Carrion Crows, which gathered in the evening, 

 first to drink (not in the rushing Aar, but in a 

 stream quiet enough to give me a momentary view 

 of a Kingfisher) ; then to perch on a number of 

 small fruit-trees, and finally to wheel" round and 

 round among the pines and precipices, until they 

 settled down to roost for the night. But for their 

 voices and their black bills, it was hard to believe 

 that they were not rooks ; but no rook was visible, 

 and this bird seems almost unknown in the valley. 

 After seeing this strange sight, I find it hard to 

 assent to the universally accepted proposition, that 

 the Crow is never, strictly speaking, a gregarious 

 bird. So constant is their habit here of roosting 

 together, that Anderegg told me that he had more 



