Mystery mystery

field recording undetermined (sex) uncertain No modification to recording. Bird was unseen. Sunny, pleasant day. . . Songs at 8 sec, 14 sec, 23 sec; two part song -- initial trill and 6-7 rapid individual notes with the same pitch. . The bird was singing from the edge of an open cornfield and a yard with large deciduous trees. I could not determine whether the sound came from the field or the trees (probable, but not positive). Suggestions have been young sparrow type (too early in the year in my mind and too consistent), Blackburnian Warbler, Cape May Warbler, and Tennessee Warbler (late for any of these, but possible).; animal seen:no; playback used:no