National Geographic Magazine/Volume 31/Number 4/Friends of Our Forests/Tennessee Warbler
The Warblers of North America
Range: Breeds in Canadian Zone from upper Yukon Valley, southern Mackenzie, central Keewatin, southern Ungava, and Anticosti Island south to southern British Columbia, southern Alberta, Manitoba, northern Minnesota, Ontario, New York (Adirondacks), northern Maine, and New Hampshire; winters from Oaxaca to Colombia and Venezuela.
The Tennessee warbler is by no means as local as its name would imply, but is likely to be found in migration almost anywhere in eastern United States, although it is much more numerous in the Mississippi Valley. Unpretentious both in dress and character, this little bird seems to possess no very salient characteristics. It is, however, not likely to be mistaken for any other species save the Nashville, which it resembles rather closely. During spring migration the Tennessee is apt to be overlooked, since it is prone to keep in the tree-tops. In fall, however, it is found lower down, usually in company with flocks of other warblers, among which it becomes conspicuous by reason of its very inconspicuousness and in contrast with its more gaudy fellows.
Its song has been variously described and may be said to be a simple trill not unlike the chippy. It appears to be certain that the Tennessee, like the Nashville, nests on the ground, but apparently the nesting habits of the bird are comparatively unknown, or at least have not as yet been very fully recorded.