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

Description

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.

Voice

Wheezy and guttural whistling notes and various squeaks and squeals.

Listen

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

Habitat

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

Range

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

Discussion

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.

Nesting

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

Similar Species

adult, breeding

European Starling

7 1/2-8 1/2" (19-22 cm). Smaller than a robin. A short-tailed, chunky, iridescent black bird; long pointed bill, yellow in summer and dark in fall and early winter.

adult male, breeding

Rusty Blackbird

9" (23 cm). In spring males are black, with a bluish and greenish iridescence; females are dark gray. In fall they are much more rust-brown, especially head, breast, and back.

adult male

Brewer's Blackbird

8-10" (20-25 cm). Robin-sized. Male is solid black with purplish-blue iridescent head and yellow eyes. Female is gray with dark eyes.

adult male

Brown-headed Cowbird

6-8" (15-20 cm). Male black with glossy brown head; female plain gray-brown. Both have a finch-like bill.

adult male

Shiny Cowbird

7-8" (18-20 cm). Male purplish black glossed with blue above, shining purplish black below. Female grayish brown, paler below. Bill large, conical, and black. Eyes dark.

adult male

Boat-tailed Grackle

Males 16-17" (41-43 cm); females 12-13" (30-33 cm). Tail very long and keel-shaped. Male black, iridescent blue on back and breast; yellow or brown eyes. Female smaller, brown with paler breast.

adult male

Great-tailed Grackle

Male, 16-17" (41-43 cm); female, 12-13" (30-33 cm). Tail very long and keel-shaped. Male black, with iridescent purple on back and breast. Female smaller, brown with a pale breast.

adult male Coastal (Purple)

Common Grackle

12" (30 cm). Jay-sized. Long, wedge-shaped tail displaying a longitudinal ridge or keel when in flight.

Vireo

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