Acoustic call library and detection distances for bats of Swaziland

Bats are a critical component of most terrestrial systems, yet accurately assessing species richness and abundances remains a challenge. The use of acoustic monitoring has increasingly been used to assess bat communities. Compared with more traditional trapping surveys, acoustic monitoring is relatively easy to use and vastly increases the amount of data collected. However, the ability to accurately identify bat calls from acoustic detectors is limited by the availability of regional call libraries describing the calls of local species. Further, the lack of knowledge of detection distances for different species limits the ability to compare activity levels or abundances between species. We developed an echolocation call library based on zero-crossing recordings with Anabat Express detectors that can be applied broadly to bat acoustic detector surveys across the savanna systems of Swaziland and South Africa, and potentially the broader region of Southern Africa. We also compared detection distances for different species and provide a correction factor that will increase our ability to accurately compare activity between different species.