MIGRATION. 47 



migration ; migration, that is, on a large scale, where the birds 

 leave the country entirely, and also on that limited scale, which 

 we call in England ' partial ' migration. I am obliged to speak 

 with hesitation on this subject, as it has been of course impos- 

 sible for me to make any observations on it myself. But as I 

 feel convinced that the very difficult question of migration on a 

 large scale will be eventually explained by careful attention to 

 the facts of migration on a small scale, which is constantly going 

 on unnoticed around us, I believe that Switzerland will some 

 day win the attention of the ornithologists as being one of 

 the best of all European countries to serve as a centre of ob- 

 servation. We wiU pause for a moment to glance at it in this 

 light. 



We need hardly look at the map to see that the huge mass of 

 the Alps lies directly in the path of the great yearly migration 

 of birds fi-om south and east into northern Europe. The 

 question arises at once, does this immense mountain range, with 

 its icy peaks and wind-swept passes, act as an obstacle to the 

 travelling birds, or do they rise to it and cross it, without going 

 round, into the plains of North Switzerland and Germany] I con- 

 fess that I should like to be able to answer this question with 

 greater certainty: but I believe the right answer, in the rough, to 

 be as follows. In the first place a large number of species never 

 attempt to cross the mountains, but remain in the great basin of 

 the Po, and in southern France, the whole summer, thus making 

 the avi-fauna of Lombardy distinct in many points from that of 

 Switzerland. If we look through the works of Dresser, Gould, 

 or Bree, on European birds, with the object of learning some- 



