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Brown-headed Cowbird

Molothrus ater ORDER: PASSERIFORMES FAMILY: ICTERIDAE

IUCN Conservation Status: Least Concern

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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.

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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
    • Courtesy of Macaulay Library
    © Cornell Lab of Ornithology.

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
    • Courtesy of Macaulay Library
    © Cornell Lab of Ornithology.

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.

Backyard Tips

If your backyard contains the open habitat required by cowbirds, you can attract them by spreading waste grain on the ground and leaving the grasses in your yard untrimmed. (If you have a really big yard and you really want cowbirds, you could try keeping livestock!)

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

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Cowbirds and Conservation (Audubon)

Brown-headed Cowbirds in Grasslands (USGS)

Brown-headed Cowbird: A bird that never nests has a huge impact on nesting birds.

Brown-headed Cowbirds: from buffalo birds to modern scourge (Smithsonian Migratory Bird Center)

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Search the Macaulay Library online archive for more sounds and videos