THE GLACIAL RANGE CONTRACTION, ETC. 129 



breeding in our islands refuged in the south-west (II.) 

 were fewer in number — as has previously been sug- 

 gested — and they winter at their ancient base where 

 they refuged ; the ancestors of the individuals of the 

 same species that range so high in Scandinavia had 

 their Range Base in the south-east, and they migrate 

 in autumn south-east towards that ancient refuge area, 

 none of them normally visiting the British Islands or 

 South-west Europe at all. Fortunately one or two 

 species prove, even to demonstration, that a vast emigra- 

 tion of birds did take place in this direction. The Blue- 

 throated Warbler [EritJiacus suecicd) breeds in Scandi- 

 navia, passes Central and South-eastern Europe on 

 migration, and winters in North-east Africa, south to 

 Abyssinia. The Eastern Nightingale {Erithacus pJiilo- 

 viela) breeds in Scandinavia and Denmark, passes 

 Central Europe on migration, and winters in North-east 

 Africa. The Black-throated Diver {Colymlms arcticus) 

 breeds in Scandinavia and the Baltic Provinces, crosses 

 Europe in a south-easterly direction on passage to its 

 winter quarters in the Black Sea, occasionally wander- 

 ing south to the Italian lakes, the Adriatic, and the 

 Mediterranean. I may here remark that Mr. George 

 Lindesay, in his very interesting paper, " Rambles in 

 Norsk Finmarken " {Fortnightly Review, November 

 1894, p. 674), observed and recorded this strongly 

 marked direction of the migration of birds in spring 

 to that area. He says : " Like most of the true birds 

 of passage, these small birds reach their northern 

 breeding-ground from the East, coming by way of 

 Russia and the Baltic Provinces." 



Many of the species tabulated above have ceased to 

 breed in our islands, some only in the extreme north of 



K 



