Bronzed CowbirdMolothrus aeneus

adult male, Eastern
Kevin T. Karlson/VIREO
adult female, Eastern
Brian E. Small/VIREO
immature, Western
Robert Shantz/VIREO
Bronzed Cowbird
Bronzed Cowbird


8 1/2" (22 cm). Male bronze-black with bluish-black wings and tail. Prominent red eye can be seen at close range. Female similar but duller. Brown-headed Cowbird smaller, with a distinctive brown head.


Wheezy and guttural whistling notes and various squeaks and squeals.


whistle call
gurgling song & whistle call
gurgling song & whistle call


Pastures, roadside thickets, ranches, open country generally; also parks and orchards.


Breeds in southern Arizona, New Mexico, and south-central Texas. Withdraws southward from much of Arizona during winter.


During courtship both sexes, but especially males, erect their neck feathers into a ruff. The males bow and jump up and down, whistling unmusical squeaky calls. Like their close relatives the Brown-headed Cowbirds, these birds follow livestock, especially cattle, snapping up insects flushed from the grass. They alight on the backs and necks of livestock to feed on ticks. Cowbirds also feed extensively on seeds and grain. During the colder months these birds form enormous flocks and move around the countryside with other species of blackbirds.


1-3 blue-green eggs laid in other birds' nests, particularly nests of orioles, tanagers, flycatchers, buntings, and grosbeaks, more rarely thrashers and thrushes.

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