Identify Nyctalus Bat Calls

The big bats (Noctule Nyctalus noctula, Leisler’s Bat Nyctalus leisleri and Serotine Eptesicus serotinus) have calls with lower peak frequencies than pipistrelles and, typically, with distinctive rhythms. However, they share the variability of pipistrelles’ calls and are very difficult (sometimes impossible) to distinguish from each other in woodland, when the peak frequency is raised and the distinctive rhythms tend to disappear.