Cowbirds are birds belonging to the genus Molothrus in the family Icteridae. They are brood parasitic birds.
These birds feed on insects, including the large numbers that may be stirred up by cattle. In order for the birds to remain mobile and stay with the herd, they have adapted by laying their eggs in other birds' nests. The cowbird will watch for when its host lays eggs, and when the nest is left unattended, the female will come in and lay its own eggs.
The cowbird eggs do not look much different from the hosts' eggs, and the host will normally incubate the eggs. The cowbird chicks grow quickly, and may consume most of the food the host brings. If starvation does not kill the other birds, in some species the cowbird will use its large size to push the other chicks out of the nest.
