First Record of Brown-headed Cowbird Egg in a Lesser Scaup Nest

On 16 June 1999, I found a Lesser Scaup (Aythya affinis) nest parasitized by a BrownheadedCowbird (Molothrus ater). On 22 June the female scaup had begun incubating the 10 scaup eggs but the cowbird egg was missing, presumably ejected by the female scaup.

David N. Koons, Wilson Bull., 112(4), 2000, p. 554