Cowbirds are birds belonging to the genus Molothrus in the family Icteridae. They are of New World origin, and are obligate brood parasites, laying their eggs in the nests of other species.

Icterids or New World blackbirds make up a family, the Icteridae, of small to medium-sized, often colorful, New World passerine birds. The family contains 108 species and is divided into 30 genera. Most species have black as a predominant plumage color, often enlivened by yellow, orange, or red. The species in the family vary widely in size, shape, behavior, and coloration. The name, meaning "jaundiced ones" comes from the Ancient Greek ikteros via the Latin ictericus. This group includes the New World blackbirds, New World orioles, the bobolink, meadowlarks, grackles, cowbirds, oropendolas, and caciques.