Evidence for Bachman's Sparrow Raising Brown-headed Cowbirds to Fledging

Abstract

Abstract We report the first records of Brown-headed Cowbirds (Molothrus ater) raised to fledging by Bachman's Sparrow (Aimophila aestivalis). Records are based on field observations of parasitized sparrow nests monitored during two separate avian reproductive studies. One record is of a Bachman's Sparrow nest in southwestern Florida in 2002 and four records are of unpublished data from sparrow nests in central Arkansas during 1983–1985. These observations suggest that Bachman's Sparrow can successfully raise cowbird young. Ours is also the first record of a parasitized Bachman's Sparrow nest in Florida.