46 ANNALS OF BIRD LIFE. 



season. On the other hand, such species as the 

 Hoopoe, the Avocet, and the Spoonbill, which 

 were once regular visitors to our shores, do not 

 migrate exceptionally late. These facts seem to 

 confirm the theory that those species, individuals 

 of which are purely accidental visitors in spring, 

 have only extended their range into latitudes as 

 far north as the United Kingdom since our 

 islands were detached from the Continent. They 

 were the last birds to push north again after 

 the glacial ice receded, and were evidently dis- 

 inclined to cross the waters of the English 

 Channel, which to them was a strange and un- 

 known sea. All Arctic birds are the latest of 

 migrants, tarrying in their winter quarters long 

 after birds of temperate climes have hastened 

 away, waiting for the summer, which spreads 

 rapidly over their far northern haunts with but 

 few warning signs of spring. The Great Reed 

 Warbler and the Barred Warbler do not visit us, 

 not because there are no haunts in this country 

 suited to their requirements, but because they have 

 never learnt the way across the Channel which 

 divides us now from the Continent ; the Reed 

 Warbler and the Blackcap do visit us because it 

 has been their custom to do so ever since the 

 glacial period passed away, and when this country 

 was probably a peninsula of Western Europe. 

 The following table of specific characters will en- 

 able the reader to identify any of these strangers 

 of the spring in their breeding plumage : 



