84 STUDIES IN BIRD-]MIGRATION 



either on passage to lands beyond our shores, or are 

 bent on passing the winter with us. Day after day in 

 late September, and throughout October, this stream of 

 migration, which is often of great volume, is observed 

 sweeping past the numerous lightships stationed off the 

 coast between the Straits of Dover and the Wash, 

 towards the coasts of Kent, Essex, Suffolk, and 

 Norfolk. It has its centre on the Essex coast and 

 at the mouth of the Thames, and towards these the 

 migrants proceed by a direct westerly course. Off the 

 Suffolk and Norfolk shores the stream is observed 

 moving in a north-westerly or north-north-westerly 

 direction ; . while off the Kentish coast the course is 

 south-westerly or south-south-westerly. 



These lines of flight across the North Sea seem to 

 be rigidly adhered to. The voluminous observations 

 made at the lightships clearly indicate that the birds are 

 not making for the nearest land, but are steadily 

 pursuing definite courses. This is an important and 

 significant fact, and it is fair to draw the conclusion that 

 the courses have been steadily maintained across the 

 North Sea. If this be so, and I see no reason to doubt 

 it, then this vast stream of migration flows from the 

 mouths of the rivers Maas, Schelde, and Rhine. These 

 great rivers, too, are probably the highways along 

 which this feathered stream passes to reach the Dutch 

 coast in the autumn (and up which it proceeds in the 

 spring) from wide areas in Western Central Europe. 

 The species travelling along this route also lend coun- 

 tenance to this view, for there do not appear to be 

 any essentially northern birds among them : all are 

 typical natives of Central Europe — Grey Crows, Rooks, 

 Jackdaws, Starlings, Chaffinches, Greenfinches, Tree 



