What Do Cowbirds Eat?

Video Transcript

"Brown headed cowbirds are a blackbird species. They are birds that feed mostly on insects and arthropods in the warmer weather, but in the winter and in the fall they often will feed on grain. Brown headed cowbirds are what we call brood parasites. A lot of people are not particular fond of cowbirds, because they don't build a nest, they lay their eggs in the nest of another smaller bird, and then the host the parasitized bird ends up often taking care of the baby cowbird at the expense of it's own young. So that this whole nesting behavior of parasitism is an interesting one, and may have evolved from the fact that cowbirds ancestrally in this country were species that lived mainly were in the prairies. And they followed bison, and as bison herds grazed and moved they would stir up insects, and the cowbirds would feed at their feet and snap up the insects. But because the bison was a migratory species it's thought that one of the things that may have led to the parasitic lifestyle of cowbirds is they didn't have time to stick around so they became parasites. They would drop their eggs, and then off they would go, and they would follow the bison. So insects in the summer, but then after the nesting season is over the cowbirds would begin to gather into flocks. And they would become very gregarious, and they would feed at that time on grain. And in areas where they move into areas where there is a lot of wild rice for example, or corn that is left on the ground. This kind of thing. Cowbirds can be a real problem, and because they are a very numerous bird, and because they occur in large flocks, particularly in the non-nesting season they can be a real pest as far as feeding on crops that are growing for human consumption. So it is basically grain, particularly in the non-nesting season. And insects of one sort or another mostly on the ground that they get their food."