OSTIAK BOATS 



CHAPTER XLI. 



MIGRATION. 



Climate of the Tundra Break up of the Ice Migration of Birds in the 

 South of France Comparison bet ween Island and Continental Migration 

 Routes of Migration Grouse Conservatism of Birds Mortality amongst 

 Migrants Origin of Migration Glacial Epochs Emigration of Birds 

 Geographical Distribution of Thrushes Reports on the Migration of Birds. 



THE history of animal and vegetable life on the tundra 

 is a very curious one. For eight months out of the 

 twelve every trace of vegetable life is completely hidden 

 under a blanket six feet thick of snow, which effectually 

 covers every plant and bush trees there are none to 

 hide. During at least six months of this time animal 

 life is only traceable by the footprints of a reindeer or a 

 fox on the snow, or by the occasional appearance of a 

 raven or a snowy owl, wandering above the limits of 



