Molothrus ater


Brown-headed Cowbirds are lousy parents and their eggs are parasites for broods of other birds. The Cowbird lays it's eggs in the nests of other birds, who then feed and raise the young Cowbirds as their own. The young Cowbird usually takes over the nest and the host bird's young are lost, supposedly resulting in the decline of many species (mainly songbirds). Don't judge this bird too quickly, humans have been far worse at causing the decline of many species. Efforts have been started to control and protect the size of Cowbird populations. The Great Plains are the Cowbird's original habitat. There it followed herds of Bison, which would stir up and expose insects and seeds. The birds would even pick parasites off the Bison. Hence its name. Humans brought cattle into the seen, which allowed the Cowbird to expand its range. They can now be found throught the country.


General: 6 to 8 inches in length.

Male: All black with a glossy brown head.

Female: Plain gray-brown plumage. Both have finch-like bill.


Open country and grasslands near water, backyards.


4-5 white eggs, lightly speckled with brown spots. They have a 10-13 day incubation period. Fledging occurs 10-11 days after hatching. No nest, the eggs are laid one at a time in the nests of other birds (usually songbirds).

Observed Locations:

  • Lake Murray, La Mesa
  • Wigginton Ranch, Tijuana River Valley

  Listen To This Bird ( mp3 )
         Song #1

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Copyright © Scott Streit, 2000.