Page:Popular Science Monthly Volume 30.djvu/828

804 It had long been observed that, as the sun comes to our side of the equator, the buds swell, the leaves and flowers unfold, and a sheet of verdure expands and spreads toward the pole; and closely following this there comes a mighty army of bird-life—orioles, tanagers, and warblers of brightest hue—filling every orchard, grove, and woodland with life, and song, and joy. And again, when autumn comes, the wave returns to us from the North, bringing with it the black snow-birds and other species which make their winter home with us, while the great bulk of the species pass on to the southward as mysteriously as they came.

The flight of storks has given trouble to the Germans and the Chinese, while the disappearance and the reappearance of the swallows have caused untold trouble everywhere. Learned bodies, like the French Academy and the Royal Society of London, have gravely asserted that, in the fall, swallows plunge into the mud of marshes and mill-ponds, become torpid, and hibernate like frogs and snakes. I have seen a list of nearly two hundred articles written all along from the middle of the seventeenth century down to 1877, for the purpose of proving or disproving the hibernation of swallows and other birds! And Dr. Coues says he can lay his hand upon papers of that period which discuss the migration of swallows to the moon, the falling of the little quadrupeds called lemmings in showers from the clouds, and the origin of brant-geese from barnacles that grew on trees. Indeed, not a year ago I was assured by a gentleman of more than average intelligence that this last is undoubtedly the correct theory as to the origin of the barnacle-goose! And it was not a decade ago that I read, in one of the leading newspapers of this State, an article of as curious a character. Its purpose was to explain the sudden appearance in fall of the black snow-birds, and their as sudden disappearance in spring, and the explanation given was that our common sparrows change color in fall, becoming snow-birds, which they remain until spring, when they put on their other dress and become sparrows again! And I find that, among the common people of the country, there are many who have this belief.

We have long known in a general way that the birds go southward to winter, and return to spend the summer at the North. But just where in the South do they go? Why do they go there? By what routes do they travel? At what rate of speed? Do they travel by night, or day, or both? What species migrate first, which last, and why? How are they guided in their course? What is the winter as well as the summer habitat of each particular species, when does it get there, and when does it leave the one for the other? In what way and to what extent are their movements dependent upon or influenced by vegetable and meteorological phenomena?

These are but a few of the questions which rnithologists have sought in various ways to answer. The limits of this paper will