124 Mr. W. Eagle Clarke — Bird-migration 



It is a fact worthy of mention that each of the flocks, great 

 and small, that came under observation during these great 

 cross-sea movements was composed of a single species. I never 

 saw a flock or party consisting of mixed species — each kind 

 kept strictly to itself, even when passing simultaneously with 

 others and moving in the same direction. 



An interesting problem in connection with these E. to W. 

 movements is : Whence came these vast hosts of autumn 

 migrants — continental emigrants ? 1 was somewhat uucer- 

 tain when I prepared the "Digest" in 1896. Now I am 

 decidedly of opinion that they are birds of Central (Western) 

 European origin. I have little doubt of this from their 

 lines of flight, from their species, &c. These migrants, 

 1 believe, quit the Dutch coast at the mouths of the Maas, 

 Rhine, and Schelde, which they have reached mainly by 

 pouring down the courses of these great rivers from inland 

 districts, some of which lie far away. This would account for 

 the vastness of their numbers. 



The extraordinary persistency with which these hosts 

 follow definite lines of flight during their passage across the 

 North Sea is very remarkable and also bears out my view. 

 Thus at lightships lying only a few miles off the coast, and 

 well within sight of land, the birds are not recorded as 

 making for the nearest points of the land, though they must 

 be tired after their long passage, but as persistently following 

 particular lines of flight. It is quite reasonable to suppose 

 that the same definite course has been maintained during 

 the entire journey ; and if we trace such lines back to the 

 shores of the Continent, we shall find, whether the observation 

 be made off the coast of Lincolnshire or Kent, that they 

 have their origin on that section of the coast of Holland 

 which I have indicated. 



The night-movements were of a varied and interesting 

 nature and occasionally of considerable magnitude. Some 

 of them were not difficult to interpret, while others were 

 problematical. 



I may say at once that, so far as direct observation was 



