xxxiv INTRODUCTION. 



when returning to their winter quarters to the south of our 

 Islands. The winter visitors are chiefly individuals from the 

 ranks of certain species of the birds of passage which winter in 

 the British area, and emigrate to the north-east in the spring. 



In the autumn these numerous migrants cross the North 

 Sea and arrive on the east shores of Britain at points between 

 the Shetland Isles and the Humber or the northern seaboard 

 of Norfolk. All the movements do not cover this stretch of 

 coast-line, but not infrequently such is the case, and as a 

 rule they are recorded from the greater part of the region 

 indicated. Observations prove that these migrants pass to 

 the northward or westward of the Outer Dowsing Lightship, 

 which is situated 38 miles E.S.E. of the mouth of the 

 Humber. 



After long and careful study it is decided that these im- 

 migrants and emigrants from and to Northern Europe pass 

 and repass between this portion of the Continent and Britain 

 by crossing the North Sea in autumn in a south-westerly 

 direction, and in spring in a north-easterly one,* and that 

 while the limit of their flight in the north is the Shetland Isles, 

 that on the south extends to the coast of Norfolk.! 



It is to be remarked, also, as bearing upon this point, 

 that all the species occur on migration in the Orkney and 

 Shetland Islands, but not in the Faroes. J And, further, 

 all the British birds of passage to Northern Europe are either 

 summer visitors to Scandinavia or are regular migrants along 

 the western shores of that peninsula. 



After arriving on our eastern shores, these immigrants from 



* The direction varies. It is probably more westerly (in autumn) 

 or easterly (in spring) at the most northern British stations, and south- 

 south-westerly (in autumn) or north-north-easterly (in spring) at the 

 stations on the east coast of England. 



t The formation adopted by the migrants during passage would 

 seem to be an extended line — perhaps a series of lines — whose right 

 wing extends to the Northern Islands and its left wing to the coast of 

 Norfolk. 



X A few species occur in the Faroes on migration, but they are also 

 summer visitors to those Islands and to Iceland. 



