OCCURRENCES OF THREE SPECIES OF GNATCATCHERS IN THE SAN GORGONIO PASS, CALIFORNIA

Abstract

The San Gorgonio Pass is an important zone of interchange between desert and coastal flora and fauna in southern California. We report multiple recent observations of California Gnatcatchers (Polioptila californica) within the pass, apparently persisting since their first documentation in 1908. While the Blue-gray Gnatcatcher (P. caerulea) has been documented here for more than a century, the occurrence of the California Gnatcatcher in this area is not widely known and not included in recent distribution maps for this threatened species. We also report the expansion of the Black-tailed Gnatcatcher (P. melanura) into the pass in recent decades, forming one of the few zones of overlap between these two species. With its elevational gradients, vegetation mosaics, and shifting species ranges the San Gorgonio Pass serves as a potential refugium from various anthropogenic stressors including climate change. The pass is currently subject to piecemeal development and lacks any significant conservation areas. It deserves more comprehensive conservation planning attention.