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Brown-headed Cowbird

Molothrus ater

Length: 7.75 inches Wingspan: 13 inches Seasonality: Summer
ID Keys: Black body with brown head (male)

Brown-headed Cowbird - Molothrus aterThe Brown-headed Cowbird was originally a bird of the Great Plains, following herds of bison and feeding on the insects that were stirred up.  It has undoubtedly benefited greatly from man's alteration of the landscape and introduction of grazing cattle in all parts of the country.  Cowbirds' claim to fame, however, is its characteristic brood parasitism.  As with all cowbirds, it lays its eggs in the nests of other species, leaving the host species to raise its young.  Over 150 different species have been known to unwittingly raise the young of Brown-headed Cowbirds.  One endangered species, Kirtland's Warbler, is partially managed by active removal of cowbird eggs and removal of cowbirds themselves from warbler nesting areas.


Prefers open to semi-open habitats, including woodland edges, riparian areas, farms, prairies, and residential areas.  


Seeds and insects.


Primarily forages by walking along the ground.  They also often associate with cattle, horses, or wild bison, following the large animals and picking off insects stirred up.  They will also sometimes perch on the backs of these large mammals, and it is thought they may pick ticks and insects off of the animals' backs.


May through August.  No nesting occurs, Brown-headed Cowbirds lay eggs in the nests of other bird species.  One female can be a very prolific egg-layer, laying one egg per day in the nest of another bird for up to a month or more.  Species' nests in which they deposit eggs are many and varied, from marsh-dwelling birds to birds of the forest. Over 150 different species have been documented as having nests parasitized by Brown-headed Cowbird eggs.


The song is a short series of low bubbly notes followed by thin whistling. Brown-headed Cowbirds also have a number of call vocalizations, including thin whistling, chattering, and clucking notes.


Populations throughout most of the Northern U.S. and higher elevations of the West move southward in the fall. In the eastern US and the South, Brown-headed Cowbirds can be found year-round.

Interactive eBird Map:

Click to access an interactive eBird map of Brown-headed Cowbird sightings

Similar Species:

In South Dakota, adult males are distinctive, with an obvious brown head that differentiates them from other blackbird species Species that could possibly be confused with Brown-headed Cowbirds in certain situations include the following:

Brewer's Blackbird 1 - Euphagus cyanocephalus Common Grackle 13 - Quiscalus quiscula Shiny Cowbird - Molothrus bonariensis Bronzed Cowbird - Molothrus aeneus
Brewer's Blackbird Common Grackle Shiny Cowbird Bronzed Cowbird

Conservation Status:

Brown-headed Cowbirds are likely much more widespread and abundant than before man's alteration of the landscape and introduction of grazing cattle. The cutting of forests, creation of new open spaces, and proliferation of "edge habitat" loved by cowbirds has resulted in population increases and access to many nesting bird species that were previously relatively unaffected by Brown-headed Cowbirds. Populations have shown some slight declines in recent decades, but Brown-headed Cowbirds are still very common in parts of what's an extremely broad geographic range. The IUCN lists the Brown-headed Cowbird as a species of "Least Concern".

South Dakota "Hotspot":

No hotspot necessary to report, as Brown-headed Cowbirds are extremely common across most of the state. They can be found in urban and suburban settings as well as agricultural land and more natural habitat. Large flocks are indeed often found in conjunction with cattle.

Bird Feeders:

Will attend feeders for various seeds and grains

Further Information:

Photo Information:

July 7th, 2008 - Pactola Reservoir, Black Hills of South Dakota - Terry Sohl

Additional Photos:

Click on the image chips or text links below for additional, higher-resolution Brown-headed Cowbird photos.

Audio File Credits:

Click on the map below for a higher-resolution view
Brown-headed Cowbird - Species Range Map
South Dakota Status: Common summer breeding resident throughout the state

Additional Brown-headed Cowbird Photos
Click for a higher-resolution version of these photos
 Brown-headed Cowbird 1 - Molothrus aterBrown-headed Cowbird 2 - Molothrus aterBrown-headed Cowbird 3  - Molothrus aterBrown-headed Cowbird 4 - Molothrus aterBrown-headed Cowbird 5 - Molothrus aterBrown-headed Cowbird 6 - Molothrus aterBrown-headed Cowbird 7 - Molothrus aterBrown-headed Cowbird 8 - Molothrus aterBrown-headed Cowbird 9 - Molothrus aterBrown-headed Cowbird 10 - Molothrus aterBrown-headed Cowbird 11 - Molothrus aterBrown-headed Cowbird 12 - Molothrus aterBrown-headed Cowbird 13 - Molothrus aterBrown-headed Cowbird 14 - Molothrus ater