Science Support for Recovery of Southwestern Willow Flycatcher (Empidonax traillii extimus) on Conserved Lands in San Diego County
This document summarizes scientific research to guide management and recovery of the endangered Southwestern Willow Flycatcher in San Diego County, California. A migratory riparian breeder present from May to August, the flycatcher has declined over recent decades due to habitat loss and potentially Brown-headed Cowbird parasitism. Using USGS data on population size, distribution, demography, and habitat condition, the document evaluates management and restoration opportunities, considering factors such as proximity to occupied sites, historical use, and restoration potential. Location-specific options are ranked by their likely contribution to regional flycatcher persistence, providing land and resource managers with a framework to prioritize habitat management and support species recovery.