Brown-headed Cowbird

Molothrus ater ORDER: PASSERIFORMES FAMILY: ICTERIDAE

IUCN Conservation Status: Least Concern

The Brown-headed Cowbird is a stocky blackbird with a fascinating approach to raising its young. Females forgo building nests and instead put all their energy into producing eggs, sometimes more than three dozen a summer. These they lay in the nests of other birds, abandoning their young to foster parents, usually at the expense of at least some of the host’s own chicks. Once confined to the open grasslands of middle North America, cowbirds have surged in numbers and range as humans built towns and cleared woods.

Songs

Song

Recorded by Geoffrey A. Keller
California May 2002
Female chatter and male song

Recorded by David S. Herr
Oregon June 1990
Song

Recorded by Randolph Scott Little
California June 1996

Macaulay Library

Male Brown-headed Cowbird sing a liquid-sounding series of low gurgling notes followed by thin sliding whistles, lasting slightly longer than 1 second. Song learning in cowbirds has been an interesting scientific puzzle, since the birds aren’t raised by members of their own species.

Calls

Songs and calls

Recorded by Gregory F. Budney, David S. Herr
Flight whistles

Recorded by Curtis A. Marantz
California June 1996
Female chatter

Recorded by Geoffrey A. Keller
California May 2002

Macaulay Library

Both male and female Brown-headed Cowbirds make a variety of whistles, clicking and chattering calls. You’ll often hear flight whistles, which are a series of 2–5 clear sweeping whistles with occasional buzzes or trills mixed in. Females make a distinctive rolling chatter that is very attractive to males. Males give their own chatter calls less often. Both sexes may make a short cluck note while feeding.

Search the Macaulay Library online archive for more sounds and videos

Backyard Tips

This species often comes to bird feeders. Find out more about what this bird likes to eat and what feeder is best by using the Project FeederWatch Common Feeder Birds bird list.

Even though Brown-headed Cowbirds are native to North America, many people consider them a nuisance bird, since they destroy the eggs and young of smaller songbirds and have been implicated in the decline of several endangered species, including Kirtland's Warbler and Black-capped Vireo. Cowbirds often flock with other species of blackbirds, and they may come to your yard if it contains open ground or lawn, or if you scatter grain for ground birds. If your yard is large enough to keep livestock, there's a good chance you will find cowbirds there.

Find This Bird

Look for Brown-headed Cowbirds in fields, meadows, and lawns. During winter and migration, search through mixed-species blackbird flocks and look for the glossy black plumage and subtle brown head in males and the short, stout bill and unmarked brown of females. Learn the male’s gurgling song and the female’s chatter call, and you’ll hear them often.

Get Involved

Brown-headed Cowbirds are a focal bird species for the Celebrate Urban Birds! project. Conduct a 10-minute count and record whether or not you see cowbirds.

Visit NestWatch to learn how to observe and report activity at bird nests