242 RESULTS OF THE JOURNEY 



probably determined largely by the direction of the great 

 valleys. Birds from the Mediterranean might fairly be 

 supposed to reach the Volga via the Bosporus, the Black 

 Sea, the Sea of Azov, and the river Don to Sarepta. 

 The natural course of birds from India and Persia would 

 be to the Volga by way of the Caspian Sea. The line 

 of migration would probably follow the Volga to Kasan, 



OUR HEADQUARTERS AT UST-ZYLMA 



and thence along the Kama to Perm and Cherdin, close 

 to the source of the Petchora. The course would then 

 continue down the Petchora as far as its junction with 

 the Ussa. It would then be reasonable to conclude that 

 the hardy species, which migrate early, would have 

 plenty of time to go round by Ust-Zylma ; whilst the 

 later arrivals would leave the Petchora at Ust-Ussa, and 

 cross direct to the tundra. For example, the snow- 

 bunting, hen-harrier, merlin, bean-goose, shore-lark, 

 snowy owl, wild swan, Bewick's swan, and herring-gull 



