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 Robin 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- 
