The bronzed cowbird (once known as the red-eyed cowbird), (Molothrus aeneus) breeds from the southern U.S. states of California, Arizona, New Mexico, Texas, and Louisiana south through Central America to Panama. (see range map). They tend to be found in farmland, brush, and feedlots. Outside the breeding season, they are found in very open habitats, and roost in thick woods. They forage in open areas, often nearby cattle in pastures. Their diet mostly consists of seeds and insects, along with snails during breeding season for a calcium source.

The male bronzed cowbird is 20 cm (7.9 in) long and weighs 68 g (2.4 oz), with green-bronze glossed black plumage. Their eyes are red in breeding season and brown otherwise. The female is 18.5 cm (7.3 in) long and weighs 56 g (2.0 oz). She is a dull black with a brown underbelly, and has brown eyes. Young birds have coloring similar to the females, with the exception of grey feather fringes.

Like all cowbirds, this bird is an obligate brood parasite; it lays its eggs in the nests of other birds. The young cowbird is fed by the host parents at the expense of their own young. Hosts include Prevost's ground-sparrow and White-naped brush finch. They develop rapidly, leaving the nest after 10–12 days.