San Diego Management & Monitoring Program


Southwestern Willow Flycatcher Breeding Site and Territory Summary - 2006

Type: report

Article abstract: We have learned of many new breeding sites and territories since the early 1990s as a result of extensive survey efforts throughout the Southwest. In 1993, there were only 140 known territories distributed among 40 breeding sites. The current estimate (as of 2006) is 1262 territories located among 284 sites (but remember the earlier caution about lack of standard definition for "site"). Not all of the 284 known sites are surveyed every year. The total estimated number of known territories (1262) is based on the most recent survey at all sites and does not reflect sites that were actually surveyed in a given year. At 126 sites surveyed in 2006, there were 831 territories detected. Most territories are found within small breeding sites (those sites with five or fewer territories). There are only six sites with 50 or more territories, though this comparison is confounded by lack of a standard definition of site. Most territories are found within small breeding sites (those sites with five or fewer territories). There are only six sites with 50 or more territories, though this comparison is confounded by lack of a standard definition of site. The states of California, Arizona, and New Mexico account for 88% of known flycatcher territories. Nevada, Colorado, and Utah collectively have 12% of the known territories. We have received no reporting from standardized Southwestern Willow Flycatcher surveys in Texas, and hence know nothing of the current status of the flycatcher there. Southwestern Willow Flycatchers are distributed over a wide elevation range, with most from sea level to 1600 m, but a few sites (n=3) are located as high as 2500 m in elevation. Southwestern Willow Flycatchers are distributed over a wide elevation range, with most from sea level to 1600 m, but a few sites (n=3) are located as high as 2500 m in elevation. Fewer than half (43%) of territories are in native habitat and 28% are in habitats having a 50% or greater exotic component. A large percentage of the territories in native habitat occur at one site - the Cliff-Gila Valley in New Mexico. Over 90% of territories are in habitats where willow, saltcedar, or boxelder are the dominant tree species; flycatchers breed in boxelder-dominated habitats only in the Cliff-Gila Valley, New Mexico. Fewer than half (44%) of sites are on federally-controlled lands and 28% are on private lands; these privately owned sites account for 36% of known territories. Approximately one-third (32%

Number of pages: 31

Authors: Kus, Barbara; Durst, Scott L.; Sogge, Mark K.; Stump, Shay D.; Williams, Sartor O.; Sferra, Susan J.;

Year: 2007

Volume:

Publisher: U.S. Geological Survey

Prepared for: U.S. Geological Survey;

Keywords: endangered species; southwestern willow flycatcher; USGS; willow flycatcher;

Species: Southwestern willow flycatcher