Because cowbird eggs require a shorter incubation ... Cowbirds will sometimes push other eggs out of the nest, and their oversized chicks often easily outcompete the others.

A cowbird removal program began in 1972 ... Researchers made sure that nest were checked just prior and after chicks had fledged. Nests that had >1 chick until 1-2 d before fledging were scored as ...

The common brown-headed cowbird is the most widespread brood parasite in North America. Poly­typic. Length 7.5". A smallish, compact and stocky blackbird with a short and thick-based bill ...

A cowbird removal program began in 1972 ... Researchers made sure that nest were checked just prior and after chicks had fledged. Nests that had >1 chick until 1-2 d before fledging were scored as ...