We radio-tracked 16 bats on 109 nights from June 2017 – September 2018. We calculated the 95% kernel foraging ranges (FRs) and 50% kernel core use areas (CUAs) in R. We used blacklight traps to sample insects in each of the 9 habitat types and determined the diets of bats using a DNA barcode library and analysis of each bat’s guano. Bats spent more time foraging in gulch, low-density developed, and grassland habitats, and differences existed between months (P < 0.01). The mean CUA was 3,991 hectares and the mean FR was 17,362 hectares. Bats ate primarily moths (68%), as well as flies (12%), termites (9%), crickets and katydids (5%), beetles (4%), and true bugs (2%). Native and nonnative insects were eaten, and bats were somewhat selective in prey species given the abundance of particular species found in the insect samples but not consumed. Agricultural vegetation, grassland, and low-density developed habitats had the highest dry weight values for insects, while the lowest values were from the forest woodland and high-density developed habitats. Our data suggest foraging flexibility in the species with the use of habitat types changing during different seasons.

Dave S. Johnston is an Associate Ecologist and Bat Biologist at H. T. Harvey & Associates and guides public agencies and corporations in developing science-based mitigation plans for bats and small mammals. Dave has published numerous scientific papers, has given over 100 presentations at scientific conferences, and has led many workshops on the ecology and management of bats. He also founded Team Chiroptera, an organization that helps students, particularly underserved minority students, learn science methods through studying bats. Dave currently has on-going bat research projects that focus on foraging ecology of bats in California, Hawaii, and Belize.