A MONTH ON KENTISH KNOCK LIGHTSHH* 17 



great and small, that came under observation during 

 these great 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 

 east-to-west movements is : Whence came these vast 

 hosts of autumn migrants — Continental emigrants ? I 

 was somewhat uncertain 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, 

 and other considerations. These migrants, I 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 may lie far away in the interior of Europe. 

 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 rem.arkable 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, 

 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. 



II. B 



