Bronzed Cowbird

Bronzed Cowbird, adult male; S. Padre, TX

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1. Description
2. Sound
3. Conservation Status
4. Other Names
5. Cool Facts
6. Full detailed species account

A Central American bird, the Bronzed Cowbird makes its way to the United States only in the border states and Louisiana. Like other cowbirds, the female does not make a nest, but instead lays her eggs in the nests of other bird species.

Description

• Medium-sized songbird.
• Medium-long tail.
• Bill stout and pointed.
• Male shiny black with red eyes.
• Female dull gray-brown.

• Size: 20 cm (8 in)
• Wingspan: 33 cm (13 in)
• Weight: 55-70 g (1.94-2.47 ounces)

Sex Differences

Male all black, female grayish brown.

Sound

Song short gurgling whistles. Call a harsh "chuck."

Conservation Status

Settlement of North America by Europeans has undoubtedly permitted expansion by Bronzed Cowbird into areas converted into agricultural habitats. Management concerns are more likely for host species than for the cowbird. Bronzed Cowbird parasitism has been assumed to be a factor (along with habitat loss) responsible for decreasing populations of Altamira Orioles and Audubon?s Orioles in southern Texas.

Other Names

Vacher bronze (French)
Tordo ojirojo (Spanish)
Red-eyed Cowbird (English)

Cool Facts

• Nest success for brood parasites (birds that lay eggs in the nests of other bird species) usually is best when only one parasite egg is laid in a given nest. Host nests frequently contain multiple Bronzed Cowbird eggs. Some female cowbirds peck the other cowbird eggs before laying their own eggs, effectively reducing the number of cowbird eggs in the nest.
• The maximum number of Bronzed Cowbird eggs found in one nest was 14 in an abandoned nest.

Sources used to construct this page:

Lowther, P. E. 1995. Bronzed Cowbird (Molothrus aeneus). In The Birds of North America, No. 144 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists? Union, Washington, D.C.