Page:Popular Science Monthly Volume 42.djvu/474

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THE POPULAR SCIENCE MONTHLY.

a much larger scale and much more pronounced in character, as are present in the settled Eastern portion, namely, an open grass-covered region bordered by a vast forest. The same conditions hold good as in the case of the smaller areas of field and woodland, and we are not surprised to find differences in life of a corresponding nature. A fauna and flora distinct and characteristic of the prairie region on the one hand are in contrast with a more or less distinct forest life.

America at the time of its discovery presented a vast and unbroken expanse of forest embracing all the now cleared and thickly settled portions of the Eastern wooded region. Early explorers, as their records clearly show, were forcibly impressed with this endless reach of forest. The past two centuries have witnessed the steady downfall of the woods and their conversion over a wide territory into fields of grain and grass. Conditions of a prairie nature have, in other words, been introduced into the forest region, and we are naturally led to reflect upon the effect that this has had upon the life. When the region was one unbroken forest, where were the birds that to-day are found only in our fields?

Two solutions of this problem offer themselves to the mind. There has either been a radical change of habit among certain species in the past two hundred years, or an emigration and occupancy of the new lands have taken place from the prairie regionsPSM V42 D474 Black throated bunting.jpgFig. 4.—Black-throated Bunting.on the Western border. This latter view is, I think, the more probable from the fact that all the above-mentioned field birds are found on the plains or are represented there by varieties which differ only in slight shades of color.

The range of the vesper sparrow covers the entire United States from the Atlantic to the Pacific and north to the plains of the Saskatchewan, so that it appears to be equally at home in the Eastern fields and on the Western praries. A paler variety occurs in the middle province, undoubtedly the result of the arid conditions of the region. Equally as extensive is the range of the savanna sparrow, though in the choice of localities it is not so entirely an upland bird as the vesper sparrow, haunting marshes along the coasts and river valleys as well as the higher open country. Several geographical races occur in the West and North. The little grasshopper spar-