ROUTES OF MIGRATION 213 



Azores, and Jamaica. On the other hand, as an 

 example of past local southern breeding areas and 

 therefore present limited winter range, we have the 

 Rose-coloured Pastor, a species whose breeding range 

 now extends from Italy to Lake Saisan in Central Asia, 

 but whose winter quarters arc entirely confined to India. 



The southern limit of that ancient breeding range is 

 now marked in a great many cases by the southern 

 winter limits of a species. In other cases the southern 

 limit of the Glacial (and of course Pre-Glacial) breed- 

 ing range is marked by the area occupied by a 

 sedentary southern form or representative species, 

 whose segregation is often due to isolation from the 

 northern form during the non-breeding season of the 

 former. With the Inter-polar species such as the Knot, 

 Turnstone, Curlew, Sandpiper, etc., the birds continue to 

 go as far south towards what were once their Antarctic 

 quarters, as they can find land on which to rest ; and 

 these movements unquestionably indicate that at some 

 period the migrations of those birds were absolutely 

 Inter-polar — the birds breeding at one pole and winter- 

 ing at the other. With Inter-hemisphere species such as 

 the Swallow, the birds continue to go far south into the 

 Southern Hemisphere ; and their movements also indi- 

 cate that at some remote Pre-Glacial era their breeding 

 grounds were situated low down in that hemisphere, say 

 in South Temperate latitudes, and their winter quarters 

 high up in the Northern Hemisphere. 



At the climax of the Ice Age the breeding grounds of 

 northern species, and the winter quarters of such species, 

 no matter how far south they may have extended, were 

 in the great majority of cases continuous and over- 



