CHAPTER IV 

 Altitudinal or Vertical Migration 



SOME species of birds fly hundreds of miles across 

 more or less level land to reach a summer or a 

 winter home, while others attain the same objective 

 by moving through a space of a few miles which car- 

 ries them up or down the sides of mountains. A few 

 hundred feet of altitude in these instances corre- 

 sponds to hundreds of miles of latitude. Wherever 

 large mountain ranges are found in temperate 

 regions we find regular migration taking place up 

 and down their slopes. 



Such migration may be noted in India, where bird 

 migrants from Siberia mingle on the plains with 

 others that have merely descended the near-by 

 Himalayas. Species of rosy finches, other finches, 

 and the snow partridges, from the higher altitudes, 

 migrate in winter into the foothill region, and then 

 with the coming of spring move back into the higher 

 country to breed. With them come woodcock, jack- 

 daws, and the sprightly whistling thrushes.^ Borders 

 of streams are frequented by flocks of wagtails from 



^ Hingston, R. W. G., A Naturalist in Himalaya^ p. 258. 



