EXTENT OF MIGRATION. 49 



Extent of Migration. The extent of a bird's migra- 

 tion is, in most cases, dependent upon the nature of its 

 food. Birds that are resident in one place throughout 

 the year generally change their fare with the season, 

 and apparently feed with equal relish on seeds or insects. 

 Those that are dependent upon fruit must migrate far 

 enough to find a supply of berries, while the insect-eaters 

 are obliged to travel even farther south. 



Most of the migratory birds of our Western States 

 pass the winter in Mexico. Our Eastern Sparrows and 

 our berry-eaters, like the Eobin and Bluebird, winter 

 from the Middle States to the Gulf coast, while the ma- 

 jority of our purely insectivorous species cross to Cuba 

 and winter in the West Indies, or continue to Central 

 America and even northern South America. Snipe and 

 Plover make the most extended migrations, some species 

 breeding within the Arctic Circle and wintering along 

 the coasts of Patagonia. 



Times of Migration. Let us suppose we are about 

 to observe the spring migration of birds at Englewood, 

 New Jersey a few miles from New York city. Birds 

 arrive here about a week later than at Washington, D. C., 

 and a week earlier than at Boston. 



During January and February, while watching for 

 some rare visitor from the North, we shall find that Tree 

 Sparrows and Juncos are everywhere common. Less 

 frequently we may see Shrikes, Winter Wrens, Golden- 

 crowned Kinglets and Brown Creepers, and rarely Snow- 

 flakes, Red Crossbills, and Redpolls will be observed. 

 These birds are winter visitants, coming to us from the 

 North in the fall and leaving in March and April. 



Of course, in addition to these migratory birds, we 

 shall see most if not all of our commoner permanent 

 residents, or the birds which are with us throughout the 

 year. They are the Bob-white, Ruffed Grouse, Red- 



