Brown-headed Cowbird

To its discredit, the Brown-headed Cowbird is best known for its nest parasitism. The female lays her eggs in the nests of other song birds with the result that the unwitting host mother bird inadvertently nurtures the larger cowbird chick, which is larger and more aggressive than the host bird’s chicks, gets the lion’s share of the food, and not infrequently causes the death by starvation of the victimized chicks.  Numerous warbler species in particular fall victim to this unfortunate process.  The Kirtland’s Warbler was brought to the brink of extinction in large part because of cowbird parasitism, which led to the current program of controlling cowbirds with the judicious use of specially built traps.