Documentation of a hybrid Spizella sparrow using spectographic and genetic analysis

We report the first well-documented hybrid between Field Spizella pusilla and Clay-coloured Sparrows S. pallida. This hybrid combination has previously been suggested from field observations in eastern North America, but not confirmed. We encountered an individual in Lorain County, Ohio, USA, during surveys for the state's second breeding bird atlas. It was a territorial male, singing a buzzy but accelerating trilled song with characteristics of both parents. It responded vigorously to playback of both Field and Clay-coloured Sparrows. In the hand, the bird showed plumage characteristics of both species and intermediate measurements. Using molecular data, we were able to confirm Clay-coloured Sparrow as the mother of the individual, with support for Field Sparrow as the father. This and other recent field observations of this hybrid pairing have been reported at the eastern boundary of the expanding breeding range of Clay-coloured Sparrow, suggesting that this hybrid combination can be expected elsewhere in the Great Lakes region and in New England, where these species are increasingly syntopic.