Bird-catching on the Alps. 181 



easier) to the point where the Rhine curves round 

 to the north at Chur, the northern barrier of the 

 trench offers only these three passages to the 

 ordinary human traveller. The southern rampart, 

 though for the most part broader, and including 

 the highest European peaks, admits the traveller 

 southward at several points, and is pierced by two 

 excellent carriage roads, those of the Simplon and 

 the St. Gotthard. 



During the summer, the parts of Switzerland 

 north of the trench and its two barriers, are 

 occupied by countless fragile birds, which have 

 come from Africa over Italy, and must return 

 there in the autumn. How do they come, and 

 how do they return ? Of their arrival I have had 

 no personal experience, and shall therefore say 

 nothing ; for it does not follow that birds always 

 come and go in exactly the same manner and by 

 exactly the same route. But of the departure of 

 some of them I can now tell something, having 

 had the evidence of my own eyes that a double 

 barrier such as I have described is not a fatal 

 obstacle to their progress. The main facts of the 

 migration have indeed been long known, and only 



