The California Gnatcatcher, Polioptila californica, was recently recognized as a species distinct from the widespread Black-tailed Gnatcatcher, P. melanura, of the southwestern desert regions of the United States and Mexico (Atwood 1988, American Ornithologists’ Union 1989). Although California Gnatcatchers are distributed throughout much of Baja California, the northernmost subspecies, P. c. californica, now occurs only in remnant fragments of coastal sage scrub habitat from Los Angeles County, California, south to El Rosario, Baja California (Atwood 1991).