Page:Popular Science Monthly Volume 30.djvu/830

806 to the Union the fruits of the joint labors of this great corps of observers, together with such deductions or generalizations as he may be able to base upon them.

By noting the species which are permanent residents, which winter residents or visitants, which summer residents, and which spring and fall migrants, together with the relative abundance of each species in each locality where found, the geographical distribution of our birds has already been pretty well made out.

A like series of observations upon the time of arrival and departure of each species, the manner of its coming and going, the period of its stay, the place and time of its nesting, enables us to learn much of its life-history. And a study of meteorological phenomena, such as the direction of the wind, the temperature from day to day, the occurrence of storms, together with data regarding contemporaneous phenomena, such as the appearance in spring of the first frog, toad, or snake; the end of the period of hibernation of certain mammals; the leafing of different trees and the flowering of various plants; and the breaking up of the ice in the rivers and lakes—all these throw much light upon the causes wbich induce, and the conditions which influence or control, migration.

More than a thousand observers are now at work gathering data for the solution of these problems. Never before have so many persons worked together and systematically for the solution of any great question in science. Observers are at work in every State and Territory in the Union, besides a number in the West Indies, Mexico, and Canada. The interest of the lighthouse-keepers has been enlisted, and many of them are doing excellent service.

The most southern station in the United States is at Sombrero Key, at the southern end of Florida, while the most northern is at Point Barrow, Alaska, more than four thousand miles away. From New Brunswick and Maine on the east, the stations extend across the continent to California, Oregon, and Vancouver's Island. And from the time a bird crosses our southern border in early spring-time until it reaches its breeding-ground, wherever that may be, it is under the careful surveillance of these inquiring spies. Its every movement is watched and recorded, and by the time it has reached its summer home, reared its brood, and returned again to its winter resort, few, indeed, are the important facts in its life-history whicb have not been made a subject of note by one or another of these observers. Thus the records are made from year to year, and even now hundreds of note-books all over our country contain thousands of entries to the credit or debit of our birds for the last four years. All this, and the Union has just begun its work!

As an illustration, let me ask your attention to the record of a beautiful and familiar bird—the Baltimore Oriole. After spending the winter within the tropics, it returns to our Southern borders in