Extent of Migration.—The extent of a bird's migration 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 majority 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 Snowflakes, 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-
