The Southwestern Willow Flycatcher (Empidonax traillii extimus) is an endangered bird that breeds only in dense riparian habitats in six southwestern states (southern California, extreme southern Nevada, southern Utah, southwestern Colorado, Arizona, and New Mexico). Since 1993, hundreds of Southwestern Willow Flycatcher surveys have been conducted each year, and many new flycatcher breeding sites located. This document synthesizes information on all known Southwestern Willow Flycatcher breeding sites. This rangewide data synthesis was designed to meet these objectives:
* identify all known Southwestern Willow Flycatcher breeding sites, and
* assemble data on population size, location, habitat, and other information for all breeding sites, for as many years as possible, from 1993 through 2006.
This report provides data summaries in terms of the number of flycatcher sites and the number of territories.