San Diego County-wide Pallid Bat and Townsend’s Big-eared Bat Surveys

Led by Bat Biologist Drew Stokes, the BioServices team conducted county-wide surveys for two California Species of Special Concernpallid bat and Townsend’s big-eared bat—for which updated status and distribution information was needed to inform San Diego Management and Monitoring Program efforts, and region-wide planning and conservation efforts.

The research goals of this study were to: (1) document presence, including day and night roost locations, of the two focal bat species; (2) determine current population status and demographics and provide a comparison of results to baseline 2002-2003 bat surveys; (3) obtain tissue for genetic analyses of population structure; (4) provide data for use in habitat modeling for Multiple Species Conservation Program (MSCP) planning; (5) determine the health of bats; and (6) document the diversity of bat species within the MSCP areas.

Biologists employed a wide variety of survey methods: acoustic surveys using bat detectors and the unaided human ear, temporary capture using mist-nets, and direct inspection of potential day and night roost locations.

During this study, data were collected on 18 of the 22 bat species known from San Diego County; these 18 species included the two focal species as well as six additional California Species of Special Concern. Based on these data, the team was able to fill in information gaps, identify areas of high conservation priority, and provide area-specific management recommendations to benefit pallid bat, Townsend’s big-eared bat, and multiple co-occurring bat species.