Brown-headed Cowbirds are small dark birds, related to orioles, grackles and blackbirds. Males have iridescent black bodies with brown heads; females are much duller, with a brownish-grey overall plumage.
Brown-headed Cowbirds are brood parasites. They do not make their own nests; females lay eggs in the nests of other birds. Baby Brown-headed Cowbirds are raised by the host parents; more than 140 different species of birds have been seen raising baby Brown-headed Cowbirds.