July 2021
Bird of the Month
by
Russ Chappell

Brown-Headed Cowbird

Brown-headed cowbirds have an unorthodox method of raising families. While the non-monogamous male plays the field, impregnated females forego the boring task of nest-building and simply deposit their eggs (up to 36 per season) in a host species’ nest!

The chicks are born naked except for scant clumps of down, eyes closed and helpless. But since they usually grow faster than their nestmates and are aggressive, they receive more attention and food than the foster parents’ actual offspring, and they thrive, often at the expense of the host’s young.

Though the cowbird’s behavior suggests poor parenting skills, it’s noteworthy that parents often return to the host nest to check on how their abandoned chicks are doing!

Brown-headed cowbirds frequent fields, meadows and lawns, often mixing with other blackbird flocks. Even in a mixed flock the males stand out because of their glossy black feathers and brown heads, while the females display an unmarked brown appearance. The male’s loud gurgling call and the female’s constant chatter also help identify them.

These ground-feeders may visit backyards where grain has been scattered, or may visit bird feeders. When not displaying or feeding, they often perch high on prominent tree branches. They also feed on insects attracted by livestock, which earned them the “cowbird” moniker in 1839.

Adult males weigh up to 1.8 ounces and are up to 8.7 inches in length, with over 14-inch wingspans. Females are slightly smaller, 1.6 ounces, up to 7.9 inches long and with wingspans under 13 inches.

Cowbirds that are permanent residents in the southern US rarely migrate, while northern birds travel to the southern US and Mexico for winter, returning to their customary summer habitats around March or April.

Rated a seven of 20 on the Continental Concern Score, they are not on the 2014 State of the Birds Watch List.

These lively, noisy and energetic birds are fine candidates for a Big List, so keep your eyes and ears open around large flocks of blackbirds. Happy Birding!

The Prescott Audubon Society is an official chapter of the National Audubon Society. Check it out online at PrescottAudubon.org.