The buffalo and the cowbird have a symbiotic relationship, where the cowbirds eat the insects kicked up by the buffalo as they feed on grass. The cowbirds follow the buffalo and other cattle in search of the insects and historically kept to American grasslands. In modern times, cowbirds are considered parasitic birds and can be found throughout the United States.
While cowbirds get their name from their symbiotic relationship with buffalo and other cattle, they are best known for being a brood parasite. Cowbirds will typically lay their eggs in the nest of other birds. As a result, the host birds raise the young cowbirds as their own, often at the expense of their own eggs. Hosts that reject the eggs of a cowbird risk having their own eggs destroyed by the female cowbird.