Southern Sierra Research Station

...conserving biological diversity through research

Southwestern Willow Flycatcher KRV Research

We have monitored a population of endangered Southwestern Willow Flycatchers (Empidonax traillii extimus) on the South Fork Kern River since 1989. We have been particularly interested in understanding the consequences of Brown-headed Cowbird (Molothrus ater) parasitism for flycatcher reproductive success and population dynamics. Despite control efforts that have effectively reduced parasitism rates and increased reproductive success, the Southwestern Willow Flycatcher population in the Kern River Valley has yet to increase in size. We are currently investigating the roles that habitat quality, food abundance, and geographic isolation play in limiting population growth