Brown-headed Cowbirds

Brown-headed Cowbirds (Molothrus ater) have returned to the Visitor Center feeders, gathering in groups of three or four to eat from the ground and platform feeder. Cowbirds are members of the blackbird family and have a very “hands-off” parenting style. They are brood parasites, meaning they rely on other birds to raise their young. A female cowbird will lay one or more eggs in the nest of another passerine who acts as the host, raising the cowbird nestling as their own. Occasionally the host species will reject the cowbird egg or nestling, which can result in cowbirds returning and destroying the nest or the host species abandoning the nest entirely. Accepted cowbird nestlings often outcompete their nestmates for nutrients, resulting in starvation for nestlings of the host species. Both rejection and acceptance can be incredibly costly to the host species, making the brown-headed cowbird an unpopular backyard bird for many nature enthusiasts.

Photo by Bill Moses.