| Gray bats (Myotis grisescens) were listed as endangered in 1976 because of declining populations resulting from cave disturbance. The Gray Bat Recovery Plan recommends further study on foraging habits and home range. Yet, few data exist partly because gray bats have large home ranges, making ground-based tracking methods problematic. Accordingly, the objective was to assess gray bats' foraging habits using aerial tracking. In 2014-2015, five maternity sites in Arkansas were harp-trapped, and 112 adult reproductive female gray bats were radio-tracked from a Cessna 182 Skylane, gathering 1,293 time-independent locations from June 15-July 15. Fixed-kernel density with least square cross validation was used to determine home range (95% of locations), core-foraging area (50% of locations), and Minimum Convex Polygon of a sub-sample of 42 individuals with ?15 independent locations. In 2014, mean 95% home range was 362.2 km² (SE= 24.9 km²), and 50% core-foraging was 83.2 km² (SE= 25.2 km²). In 2015, mean 95% home range was 57.9 km² (SE=8.6 km²), and 50% core-foraging was 13.0 km² (SE= 2.2 km²). A compositional analysis revealed that female gray bats traveled and foraged over water proportionally more than expected based on availability across the landscape when compared to other habitat types. With such large home ranges, management strategies for gray bats should go beyond protecting roost sites to include waterways and riparian areas for travel and foraging on sensitive aquatic insect species. |
