Virginia Warbler Parasitized by Cowbird
Virginia Warbler Parasitized by Cowbird.-The restricted range and elusiveness of the Virginia Warbler (Vermivora virginbe), together with its well-hidden nest, probably account in a large measure for the fact that it has so long escaped inclusion in Herbert Friedmann’s extensive lists (The Cowbirds, 1929; Auk, 60, 1943:350-356; Auk, 66, 1949:154-163) of birds known to be parasitized by the North American Cowbird, Molotkrus atey. I am able to add it to the list through the cooperation of Robert J. Niedrach, who took me to the nest of a Virginia Warbler in Daniels Park, near Denver, on July 13, 1949. When Niedrach found the nest in a bunch of grass at the edge of a clump of mountain mahogany (Cercocarpus purvifolius) about two weeks earlier, it had contained several eggs of the warbler and one cowbird’s egg. At the time of our visit, however, it was occupied by only one weak little warbler almost smothered beneath a lusty young cowbird. The cowbird involved was Molotkrus ater artem&& which, with the addition of the Virginia Warbler to Friedmann’s lists, is now known to parasitize 110 species and subspecies.-FRANK C. CROSS, Silver Spring, Maryland, September 26,1949.