Photos and article by Charly Mann
At one time much of the central part of the United States was plains where large herds of Buffalo roamed. In those days the most common bird on prairie was the Brown-headed Cowbird. Males would follow the herds through the prairies picking off insects from the back of bison. Females on the other hand had to fend for themselves, since Buffalo roamed far from the Brown-headed Cowbirds nests. As a result, female cowbirds became one of the few species of birds that were single parents. Over time females longed to follow the Buffalo herd with the males and learned to leave their eggs in the nests of other species of birds. Some birds actually recognize that the "new" eggs they found in their nests are not their own and destroy them. Because of this, Cowbirds have to be more sexually active than most birds to produce more eggs. Unlike many bird species cowbirds are highly promiscuous.
Male Brown-headed Cowbird photographed near Bartlesville, Oklahoma
The Brown-headed Cowbird is called a brood parasite because the female lays her eggs in the nest of other bird species. There are more than 140 bird species that have been documented as becoming hosts of Brown-headed cowbirds' offspring including the Eastern Meadowlark. Often the female cowbird destroys the eggs already in the nest before she lays her own. The unsuspecting adoptive birds incubate the eggs and then become surrogate parents for the baby cowbird. As the cowbird matures it instinctively leaves its adoptive parents to live with other cowbirds.
Female Brown-headed Cowbird living near Barnsdall, Oklahoma
In Oklahoma and Texas thousands of Brown-headed cowbirds are killed every year in the belief they are reducing the population of vireos, warblers, and other songbirds.
Buffalo living in the Oklahoma tall-grass prairie. He is part of a free roaming herd of more than 3,000 that attracts flocks of Brown-headed cowbirds.
The male Brown-headed cowbird has a sleek and dark plumage with a black body and brown head. The female is light brown and not nearly as striking as the male.
Brown-headed Cowbird on the lookout for insects and a female
With the virtual elimination of the Buffalo and the open prairies, Brown-headed Cowbirds now live near farms and open fields to be near to cows.