Cowbirds are six to eight inches long, with short, conical bills and short tails.
Males have brown heads and glossy black bodies. The females have gray-brown plumage and make a chattering call. Pay particular attention to any females around the next you are observing, because cowbirds are brood parasites. Click here to hear their Song. The host bird does not distinguish between its own eggs and those of the cowbird, and raises the cowbird chick as its own offspring.