Distribution of the Spotted Bat, Euderma maculatum, in California

Abstract

There were 14 records, including the type, for Euderma maculatum in California between 1891–1991. All involved salvage of single bats; most indviduals were dead or moribund. In surveys from 1992 to 1997, using primarily acoustic sampling at possible foraging sites within a few kilometers of fractured resistant rock cliffs, 23 additional localities were identified, including a range extension into the Klamath Mountains of northwestern California. E. maculatum typically was encountered foraging in meadows on the edge of forests in mixed conifer-hardwood habitat at elevations of 800–1,500 m, but observations extend to 2,926 m in the Sierra Nevada. Usually one E. maculatum was observed at a foraging site, but occasionally two or three were present simultaneously. These records suggest that the species, while typically at low density within a few kilometers of geomorphically defined roosts, occurs more widely than previously realized. Although its foraging style and characteristics of its call are distinctive, E. maculatum overlaps extensively both in geographic range and use of roosts in rock cliffs with several other species of bat, notably Eumops perotis, which also has an audible echolocation call. The linked pattern of rarity, patchy distribution, and restrictive roosting requirements place this species at risk.