Bronzed Cowbird

Molothrus aeneus

Bronzed Cowbird, Molothrus aeneus, photo © by Michael Plagens

Observed in a woody area along the Santa Cruz River in southern Arizona. 30 July 2010. The male's red eye shows clearly.

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Some bird lovers express disdain for these fascinating birds despite their gaudy plumage and a unique repertoire of sounds. It's their habit of putting their eggs in the nests of other birds that they object to. This of course is the error of projecting human values into the animal world. Cognizant naturalists should instead take time to investigate the specifics of this behavior. What bird species are they choosing to host their eggs and raise their young? How do the hosts modify their nest guarding and building behaviors when cowbirds are a threat? Do host species gain anything from this parasitic relationship?

The gaudy male below was found in Phoenix. He was among several males in pursuit of a female of his kind on 20 April 2014. Brown-headed Cowbirds are more frequently found in Phoenix. Are they parasitizing the same host species?

Summer Resident - Migration to Neotropics for winter months

Icteridae -- Blackbird Family

Bronzed Cowbird, Molothrus aeneus, photo © by Michael Plagens

More Information:

Arizona Naturalist
Sycamore Canyons
The Fauna of Arizona's Sycamore Canyons


Copyright Michael J. Plagens, page created 17 Jan. 2013,
updated 20 April 2014