_Spring._--From its winter home in Central America the blue-winged warbler seems to migrate from Yucatán straight across the Gulf of Mexico to the Gulf States and along the eastern coast of Texas to Louisiana. It is apparently very rare anywhere in Florida or the Keys, and along the Atlantic coast, where it is comparatively rare, it is found at low elevations. It migrates northward mainly west of the Alleghenies, seeming to avoid the mountains; the main body of the species seems to travel through the Mississippi Valley to the centers of abundance in the central States. Perhaps the birds that settle in southern New York and New England travel up the Ohio River, drifting through Pennsylvania and New Jersey to their destination. According to Milton B. Trautman (1940) this warbler seems to be a rare or uncommon spring migrant in central Ohio, and "in some migrations only 2 individuals were noted" at Buckeye Lake; this adds support to the theory that the birds follow the river along the southern border of the State. _Nesting._--Although Wilson (1831) gave a very good description of the nest of the blue-winged yellow warbler, very little was known of its nesting in southern New England prior to about 1880, when nests were found in southern Connecticut, where it is now known to be a fairly common breeder. I found two nests near West Haven, Conn., on June 8, 1910; both were close to the ground but not quite on it; one was in a clump of blackberry vines, weeds, and grasses, in a swampy corner of a scrubby lot; the other was in a bunch of grass and rank weeds on some sprout land among some mixed bushes. Again, on June 1, 1934, I photographed (pl. 12) a nest near Hadlyme, Conn., on the edge of an open, neglected field and close to the border of some young woods. It was built among and attached to the upright stems of a clump of tall goldenrod. These were all typical of the nests described below. Massachusetts nests are very rare; Forbush (1929) gives but two nesting records for this State, and only one for Rhode Island, though I am confident that its breeds regularly in the latter State. Horace W. Wright (1909b) gives a very full account of a nest found near Sudbury, Mass., in some mixed woods, placed between the exposed roots of a decayed stump and partially concealed by a growth of ferns. T. E. McMullen has sent me the data for several Pennsylvania nests, three in old fields, one under a cherry sprout, one under a small bush, and one 6 inches up in a tussock of goldenrod; another was under a birch sprout along the edge of an old woods road. The nest of the blue-winged warbler is unique and quite distinctive, often shaped like an inverted cone, usually very narrow and very deep and supported by a firm cup of strong, dead leaves. I cannot improve on the excellent description given to Dr. Chapman (1907) by Frank L. Burns as follows: