Hybridization between Clay-colored sparrow and Field sparrow in northern Vermont

A male sparrow showing hybrid characteristics between Clay-colored (Spizella pallida) and Field sparrows (Spizella pusilla) was first observed in Grand Isle, Vermont, in 1997. In 1998, the same hybrid defended a territory and mated with a female Field Sparrow. The pair produced one fledgling. The hybrid's signature song was composed of the buzzy notes of a Clay-colored Sparrow rising to a final trill as if copying a Field Sparrow's accelerating clear whistles.