Avise's Birds of the World

Brown-headed Cowbird
Molothrus ater

Native Range: North America and Middle America

Notes: an obligate interspecific brood parasite, meaning that it lays eggs in the nests of other species (such as warblers) and leaves the rearing of offspring to the unwitting foster parents; formerly followed buffalo herds across North America but now often associated with domestic cattle, hence the bird's name; sometimes the brood parasitism becomes so prevalent that it presents a serious threat to some already endangered species such as the Kirtland's Warbler and (Least) Bell's vireo.