Brown-headed Cowbird (Molothrus ater)

This young male cowbird is molting out of its drab brown juvenile plumage into black adult plumage. These transitional pied birds are highly variable and may cause confusion when trying to identify them based on matching pictures in a field guide. This species is famous as an "obligate brood parasite" in which the eggs are laid in the nests of other species which foster the baby cowbirds, often to the detriment of their own young.