This warbler seems to be a rare spring migrant through Florida; A. H. Howell (1932) gives seven records, from Key West to Pensacola, in March and April. The few records available seem to indicate that the main migration route is along the eastern coasts of Central America (Dr. Skutch tells me that he sees it both spring and fall in Costa Rica), Mexico, and Texas to the Mississippi Valley, whence it spreads out to reach its wide breeding range. Some birds may reach Florida via Cuba, and we have some evidence that it migrates across the Gulf of Mexico. It is common on the coast of Texas in spring. Gerald Thayer wrote to Dr. Chapman (1907) that about Monadnock, N. H., the Tennessee warbler is "very rare, and seemingly irregular. It haunts blossoming apple trees, big elms, and roadside copses of mixed deciduous second growth." At Buckeye Lake, Ohio, according to Milton B. Trautman (1940), "the daily and seasonal numbers of no warbler species fluctuated as greatly as did those of the Tennessee Warbler. During some spring migrations it was decidedly uncommon, and never more than 5 individuals were recorded in a day nor more than 35 for the spring. During other years as many as 250 individuals (May 16, 1929) were observed in a day, and more than 800 were noted during the migration. * * * The birds in spring chiefly inhabited the upper half of the taller trees of both upland and lowland wooded areas and also the upper parts of rows or groups of tall trees along the lake shore, streams, and about farmhouses." It must have been a very common migrant in Minnesota at one time, for Dr. Roberts (1936) writes: Formerly, when all Warblers were more abundant than now, the little Tennessee flooded the tree-tops for a week or ten days in such numbers as to equal, if not excel, all other species put together, excepting only the Myrtle. Insignificant in size and inconspicuous in garb, it made up for these shortcomings by numbers and incessant vocal effort, indifferent performer though it is. It is still one of the commonest species. It keeps well up among the topmost branches and moves restlessly about in search of food, singing meanwhile with little apparent effort and announcing its passage from one tree-top to another by a succession of sharp little _yeap-yeaps_ that are almost as characteristic to the trained ear as the song itself. A. D. Henderson, of Belvedere, Alberta, tells me that the Tennessee warbler is probably the most numerous of the warblers which spend the summer in the territory around Belvedere and in the Fort Assiniboine District. It breeds mainly in poplar woods, but I have also found nests in dry muskeg.