66 THE MIGRATION OF BRITISH BIRDS 



There seems little doubt that the species mentioned 

 in this table were able to live during these last cold 

 periods of the Glacial Epoch on our southern coasts — 

 then extending much further south towards the Bay of 

 Biscay — or in suitable inland districts as far north as 

 our first Refuge Area extended. Many of these species, 

 it will be seen, were aquatic birds, able apparcntl)- to 

 subsist anywhere near to open water ; whilst the others 

 were hardy species living on Arctic berries, seeds, shoots, 

 and buds, and on their smaller and more helpless com- 

 panions, as well as on the various animals that we know 

 also survived the glacial invasion of the land. Trees 

 were entirely absent from the British or most northern 

 portion of this Refuge Area, or were too small and 

 stunted for the requirements of Woodpeckers (Piciike) 

 and other arboreal species. Hence the non-migratory 

 habits of these birds. It may be remarked that every 

 one of the birds included in this table could have lived 

 in winter in such an area ; if they could not they 

 would assuredly have vanished for ever, as we have 

 uncontrovertible evidence to show that the food on 

 which they are known now to subsist was then actually 

 obtainable. 



As further confirmation that these birds formed the 

 avifauna of this area during the Ice Age, we may men- 

 tion that not a single species is represented in the south 

 by an allied race. Broadly speaking, then, not one of 

 these species dwelt south of our first Refuge Area, for 

 not one down to the present day normally wanders 

 south of that area, and not one is represented south of 

 it by a closely allied form which would indicate a 

 southern Range Base and contraction of range by ex- 



