Brown-headed Cowbird (Molothrus ater)

Brown-headed Cowbird
Brown-headed Cowbird, male - Wellfleet Bay WS, MA
© Tom Benson
Brown-headed Cowbird
Brown-headed Cowbird, female - San Diego, CA
© Tom Benson

The Brown-headed Cowbird is common on campus from March through August, but rare between September and February. It is a common year-round resident in southern California. Brown-headed Cowbirds are parasites that lay their eggs in the nests of other species, often times to the detriment of the host species' young.

High Count: 10, Average Count: 2-4 Mar-Aug, 1-2 Sep-Feb

Adult male Brown-headed Cowbirds are entirely glossy black with a rich, brown head. Females and juveniles are brownish overall, and can be distinguished from female and juvenile Brewer's Blackbirds by their short, conical bills.


Links to more information: