A NEW SITE OF SYMPATRY OF THE CALIFORNIA AND BLACK-TAILED GNATCATCHERS IN THE UNITED STATES

Abstract

Within its current range in the United States, the California Gnatcatcher (Polioptila californica) frequents low scrub on the coastal side of the Peninsular and Transverse Ranges in southwestern California. The closely related Black-tailed Gnatcatcher (Polioptila melanura) generally inhabits the Colorado and Mojave Deserts within its range in southern California. Atwood (1988) discovered that both species coexist in limited areas of northeastern Baja California. This note reports a new site of sympatry (co-occurrence) of the two species on the U.S. side of the border.