The Bronzed Cowbird is a cowbird species of Central America and Mexico with a range that crosses into the southwestern United States. Like the more common and widespread Brown-headed Cowbird of the U.S., Bronzed Cowbirds are brood parasites, laying their eggs in the nests of other species. Female Bronzed Cowbirds will lay a single egg in the nest of another species about once a week, a behavior that may last for several weeks. She will also often destroy existing eggs in the nest, leaving the parent to raise her young. As with the Brown-headed Cowbird, they appear to have adapted well to a human presence, and have significantly expanded their geographic range over the last 100 years. They used to be absent from Arizona, but are now commonly found there, and are also much more common in Texas than they were historically.
Habitat
Found in a variety of semi open habitats, from the edges of woodlands to open agricultural fields and grasslands.
Diet
Feeds on seeds and insects.
Behavior
Most foraging is done by walking on the ground. Like other blackbird and cowbird species, they will sometimes associate with cattle in order to forage on insects kicked up by their grazing activity.
Nesting
The Bronzed Cowbird doesn't build its own nest, but lays its eggs in the nests of other birds. Females are often rather prolific egg layers, and may lay a single egg a week for several weeks, taking advantage of variable breeding times of multiple bird species.
Song
Song of a Bronzed Cowbird is a mellow, ascending, whistled song with a gurgling phrase at the start and finish.
Migration
Considered a permanent resident in Mexico and Central America. In the northern part of their range in the U.S., most birds move a short distance southward for the winter, although small numbers may be found locally in the desert Southwest in winter. Some also tend to move eastward in the fall, with strays sometimes reaching as far east as Florida.
Interactive eBird Map
Click to access an interactive eBird map of Bronzed Cowbird sightings
Similar Species
Most similar to Shiny Cowbird. The Bronzed Cowbird is larger and sturdier with a thicker bill, distinctive red eyes, and a ruff of neck feathers that gives it a hunched appearance. In contrast, the Shiny Cowbird is more slender with dark eyes and a uniform, mirror-like purple or blue iridescence across its entire body.
Feeders
Will occasionally attend feeders for various seeds.
Conservation Status
Populations are widespread and relatively common in many parts of their range. The IUCN lists the Bronzed Cowbird as a species of "Least Concern".
Further Information
- eBird - Bronzed Cowbird
- Audubon Field Guide - Bronzed Cowbird
- Cornell Lab of Ornithology - All About Birds: Bronzed Cowbird
Photo Information
Photo taken by Terry Sohl - May 7th, 2008 - Near Tucson, Arizona
