SEX-SPECIFIC FEEDING HABITS OF BROWN-HEADED COWBIRDS IN NORTHERN OHIO IN JANUARY

Authors

Richard A. Dolbeer, U.S. Fish and Wildlife Service, Denver Wildlife Research CenterFollow
Cynthia R. Smith, U.S. Fish and Wildlife Service, Denver Wildlife Research Center

Date of this Version

January 1985

Comments

Copyright © 1985 Ohio Acad. Sci.

Abstract

We examined the stomach contents of 57 brown-headed cowbirds (Molothrus ater) collected from a roost in Erie Co., Ohio, on 12 January 1983. Corn was by far the predominant food, averaging 66% of the stomach contents by weight. Seeds from at least five grasses, but primarily Setaria spp., were the second most abundant food category, averaging 21% of the stomach contents. Ragweed {Ambrosia artemisiifolia) seeds (2.6%) were third. Male cowbirds consumed more corn than did the smaller females, whereas females consumed more of the smaller grass seeds. The abundance of corn in harvested fields and feedlots, combined with mild winter conditions, probably were the primary reasons cowbirds could overwinter several hundred kilometers north of their usual winter range.