242 JUNGLE FOLK 



The two common crows of India afford an excellent 

 illustration of the way in which allied species differ 

 in their power of adapting themselves to variation in 

 climate. The grey-necked species (Corvus splendens) 

 is found throughout the length and breadth of the 

 plains of India, but does not ascend the Himalayas 

 to any great height, and is, in consequence, not foimd 

 in Murree Mussoorie or Naini Tal. The corby (C. 

 macrorhynchus) , on the other hand, is found in all parts 

 of the plains save in the Punjab, and ascends the Hima- 

 layas up to 10,000 feet or higher, and is the only 

 crow that occurs in most of the Himalayan hill stations. 

 It is thus evident that the black species is far less 

 sensitive to cold than the other, but why does it occur 

 so sparingly in the Punjab ? The connection between 

 climate and the distribution of birds is a fascinating 

 subject about which very little is known. Possibly 

 in the varying sensitiveness of birds to climatic con- 

 ditions lies the secret of some of the phenomena of bird 

 migration. 



