Assessing the Impact of Brown-headed Cowbird Parasitism in Eight National Parks
Halterman MD, Allen S, Laymon SA. 1999. Assessing the Impact of Brown-headed Cowbird Parasitism in Eight National Parks. Studies in Avian Biology. 18:153-159
In 1995 and 1996 we conducted point count surveys and nest searches to examine the need to manage Brown-headed Cowbird (Molothrus ater) populations in eight western national parks. Our goal was to examine what impact, if any, Brown-headed Cowbird parasitism was having on passerines in the parks, and how current management practices might be affecting cowbird activity. The parks selected for this study were: Golden Gate National Recreation Area, Great Basin National Park, Lake Mead National Recreation Area, Montezuma Castle National Monument, Organ Pipe Cactus National Monument, Point Reyes National Seashore, Sequoia-Kings Canyon National Park, and Yosemite National Park. We located and monitored 1295 nests of potential cowbird hosts. Parasitism had a significant impact on host reproduction in four of the eight parks: Golden Gate, Great Basin, Lake Mead, and Montezuma Castle. All of the parks had some form of livestock within or adjacent to their boundaries (cattle or horses), and proximity to grazing was significantly correlated with parasitism rates.
- Type
- Journal Article
- Authors
- Halterman, Mary; Allen, Sarah; Laymon, Stephen
- Units
- GOGA , GRBA , LAKE , MOCA , ORPI , PORE
- Keywords
- Animals, Birds, Brood parasitism, Brown-headed cowbird, Golden Gate National Recreation Area, Great Basin National Park, Lake Mead National Recreation Area, landbirds, Molothrus ater, Montezuma Castle National Monument, National Parks, NRCA, Organ Pipe Cactus National Monument, Point Reyes National Seashore, Sequoia-Kings Canyon National Park, Want, Yosemite National Park