|DEMOGRAPHIC VARIATION IN ASSEMBLAGES OF BRAZILIAN FREE-TAILED BATS AT A MIGRATORY STOPOVER ROOST IN EASTERN NEVADA.|
| Joseph R. Danielson; Great Basin National Park; 100 Great Basin National Park, Baker, NV, 89311; firstname.lastname@example.org; Richard E. Sherwin, Jason A. Williams, Bryan T. Hamilton, Kelsey L. Ekholm|
|The Brazilian free-tailed bat (Tadarida brasiliensis) is widespread and abundant, with large aggregations often found in caves and abandoned mines. Although roosting associations of this species have been studied for decades, intensive demographic studies have seldom been conducted. The objective of this study was to evaluate demographic composition of assemblages of T. brasiliensis at a migratory stopover roost in eastern Nevada by documenting sex, age, and reproductive status from 2015-2018. Adult males dominated captures from spring until late summer when adult females and juveniles were captured with more regularity. The sex ratio of adults varied greatly each year depending on season while sex ratio of juveniles was nearly even overall. While all males were non-reproductive, female reproductive status varied within and among years suggesting some level of maternity use within the roost. Seasonal variation in demographic composition of bat assemblages at this site may provide insight into the migratory behavior of this species and the importance of protecting migratory roosts for T. brasiliensis.