Brown-headed Cowbirds are medium-sized birds, growing up to eight inches long. Male cowbirds have a black body with a brown head. Females are plain grayish-brown all over.
This bird lives in fields, forest edges, parks, and thickets.
Brown-headed Cowbirds eat seeds from weedy plants, as well as insects, including grasshoppers, crickets, and beetles. They will also eat other small creatures they can catch, such as spiders.
Copyright, Dan Sudia
What this bird is best known for is its breeding habits. These birds do not build a nest or raise their young. Instead, after mating, female cowbirds lay their eggs in the nests of other birds. Then they fly away, never to return.
Brown-headed Cowbirds depend on the owners of the nests to raise their young. The host bird will sit on the cowbird's eggs as well as its own. When baby cowbirds hatch, the host parents will feed them along with their own young. Cowbirds tend to grow quickly. This means they eat more food that was intended for the other baby birds. Sometimes they even push the young of the host parents out of the nest. These behaviors make the Brown-headed Cowbird a parasite.
There are hundreds of different species of birds that have raised cowbirds, including Northern Cardinal, Red-winged Blackbird, Eastern Phoebe, Common Yellowthroat, Common Grackle, Wood Thrush, and Indigo Bunting. Some birds recognize the eggs as not being their own. American Robins and Gray Catbirds, for instance, will throw the eggs out. Some birds build more nest on top of the cowbird egg. However, most birds do mistakenly raise the young cowbirds until they can make it on their own.
Copyright, Greg Gough
Brian D. Beer, Smithsonian National Museum of Natural History
The picture to the left shows Brown-headed Cowbird eggs in a Northern Cardinal nest. Can you spot which eggs are cardinal and which ones are cowbird?
Predators of Brown-headed Cowbirds include hawks, owls, raccoons, squirrels, and snakes.
Brown-headed Cowbirds travel in large winter flocks with other species, including Common Grackles and Red-winged Blackbirds.
Relationships in Nature:
Great Horned Owl Eastern Phoebe H Wood Thrush H
Great Horned Owl
Eastern Phoebe H
Wood Thrush H
Relationship to Humans:
Brown-headed Cowbirds help people by eating pesky insects and eating seeds of weeds so that they don't spread in gardens and lawns. They can cause problems when they are in large flocks and eat seeds of farm crops. Some bird-lovers don't like them because of the problems they cause for other birds.