15 April 2026

Brown-headed cowbirds (Molothrus ater) are the blackbird we love to hate. The female never builds a nest but instead lays her eggs in the nests of smaller birds who feed her hungry chick while their own eggs and chicks die.

This nesting strategy evolved from the cowbirds’ historically close association with grazing herds on the Great Plains. Since the buffalo were always on the move, so were the brown-headed cowbirds. Without a home to build a nest, they use the nests of other birds.

Their nomadic existence also affected their courtship behavior. Male brown-headed cowbirds do not stake out a physical territory where a single male perches to sing. Instead males gather and loudly display to attract females. Their display is like a lek except that it is always on the move.

Watch as one male cowbird displays to a female at the feeder. When he first arrives she makes her rattle sound. Another male shows up and they both display.

This month you’ll see male cowbirds displaying together in the trees to attract more females to join them. At the end of this video another female arrives.

Eventually they’ll move on and set up their mobile lek somewhere else.