AUTUMN MIGRATION IN BRITISH AREA 261 



the young. This grand autumn movement, however, is 

 most conspicuous amongst species that either winter in 

 the British Islands or pass over them to more southerly- 

 latitudes. Among our common Summer Migrants, it is 

 much more difficult to detect migration ; they disappear 

 one after the other from their accustomed haunts, and 

 rarely can we give the exact moment of their departure. 

 Owing also to the impossibility of distinguishing between 

 individuals, we cannot readily mark the passage south 

 of a portion of any species that onl}'' crosses our area 

 on migration. Sometimes, however, as I have repeatedly 

 observed, our regular breeding individuals will all dis- 

 appear, and perhaps a week or so after the species will 

 again frequent the district, this time represented by 

 coasting migrants. These remarks apply most closely 

 to inland migration ; along the coast the autumn pas- 

 sage is much more distinct and noticeable. We remark 

 precisely the same difficulties in spring. 



The autumn migration of birds begins to be apparent 

 in an average season in July. As we might also natur- 

 ally expect, the first signs of the great Southern Flight 

 are given by birds that breed in the highest latitudes, or 

 colder north-eastern continental areas. These species or 

 individuals experience the advent of winter much sooner 

 than others inhabiting more southern and western areas. 

 Autumn migration, therefore, begins not only from the 

 north, but from the north-east. Among the first 

 Passerine birds to make their appearance in our area 

 in July are the Wheatear, the Swallow, the House 

 Martin, the Pied Wagtail, the Song Thrush, the Robin, 

 the Goldcrest, the Wren, and the Starling ; among 

 other birds the Cuckoo, the Corn Crake, and the 

 Dotterel. All the birds that range far north or north- 



