EMIGRATION AND EVOLUTION. 119 



{Acrocephalns p/irag7niti.s), that are now known to 

 migrate as far eastwards in spring as the valley of 

 the Yenesay, return to Africa to winter ! The Little 

 Gull (Lams mimttus) sends out pioneers as far as 

 the Sea of Ochotsk, which return to the extreme 

 south-west of Asia and to Africa to winter with 

 the rest of the species. The Arctic Tern {Sterna 

 arctica) is only found during winter in the Atlantic 

 Ocean region, but in summer the range has been so 

 far extended, that a great many individuals spread 

 across Siberia to Behring Sea on the one hand, and 

 across Arctic America to that sea on the other, 

 where they breed in some abimdance. Now the 

 most astonishing part of this apparently anomalous 

 distribution, is the fact that these various species 

 go so far to winter quarters, when equally suitable 

 regions might be reached without, in some cases, 

 requiring a journey of more than a fourth of the 

 distance. It seems little short of marvellous that 

 the Rustic Buntings, for instance, breeding in Scan- 

 dinavia, should return to India and China, and 

 decline to accompany the vast number of European 

 birds that migrate south to winter in North and 

 West Africa, in whose company they have abso- 

 lutely lived all the summer ; or that the Sedge 

 Warblers breeding in the Yenesay Valley shoidd 

 come west again to Africa, parting company with 

 the myriads of Siberian birds, their neighbours of 

 the summer, leaving them to journey down that 

 great migration highway to India, whilst they 

 laboriously push on to Africa, more than double 



