February 



same place, but frequently to nest in the same 

 tree year after year, we may well believe that 

 only some strong necessity can drive them an- 

 nually so far away. 



With the exception of the very few that are 

 permanent the year round, such birds as sum- 

 mer in this region move southward in the fail, 

 not only for warmth, but doubtless, in many 

 cases, for the more potent reason that the fruit, 

 grain, insects, etc., on which they have been 

 feeding are no longer obtainable in this lati- 

 tude. Thus the bobolink is also called '' rice- 

 bird," indicating the character of its sustenance 

 while in the south. It may well be doubted 

 whether the robin lacks the physical hardihood 

 to withstand a northern winter, as it is fre- 

 quently found in New England throughout that 

 season ; but in the absence of fruits, grubs, and 

 especially earth-worms, which are its main sub- 

 sistence, it has a very precarious existence, and 

 ample cause for retirement to the south. 



On the other hand, the hardier species that 

 from one cause and another summer in the far 

 north, like nuthatches, kinglets, and crossbills, 

 coming southward at the approach of cold 

 weather, find in this latitude both a tolerable 

 climate and adequate subsistence in the eggs 



51 



