Identify Myotis and Plecotine Bat Calls

The bats of the genus Myotis, together with the Barbastelle and the long-eared bats, produce calls which are FM sweeps with no true constant frequency tails. The sound on the detector is a click, very brief and flat with no slappy quality. However, variations in the rate at which the FM sweep occurs cause some species (Barbastelle, Whiskered, sometimes Brown Long-Eared and Greater Mouse-Eared) to produce some calls which are slightly longer than the usual clicks, and are better described as tocks. Some of the species (Natterer’s, Bechstein’s and the long-eared bats) produce very quiet calls which tend to be soft ticks rather than clear clicks.