There are 17 species of bat found breeding within the UK. Below we present data tables produced from processing over 45,000 individual bat echolocation calls. These calls were collected in the UK and Eire to create a call library from which the classifiers for SonoBat UK were built.

ALL the calls were made by bats, the species of which was known. This was achieved via DNA analysis or identification in the hand. Bats were recorded along fly-ways from known roosts or released after capture and fitted with small light-tags. The calls were recorded using a variety of Full Spectrum bat detectors.

The tables below do not in themselves form an identification guide but will assist those interested in species identification. A full identification guide book will be published at a later date.

The aim of the data tables is to allow comparison of the calls made by different species. As a starting point assess the call type and then measure the duration of a particular recorded call. Then compare calls of similar type and duration. By following this method the degree of overlap between different species is reduced.

We would also recommend listing to recordings both in real time, to establish repetition and rhythm, and in Time Expansion, to establish tonal quality. This is not easy but with practice it becomes a valuable tool.

Finally, it is worth a reminder that other European bat species can sometimes be encountered in the UK. Little is understood about the migration routes of bats and vagrant bats are found from the result of weather patterns blowing bats of course or by assisted passage on ships and road transport. In a future update to the SonoBat classifiers we will include data from these species but until then it is worth keeping an open mind on any unusual calls recorded.

Call Parameter Data Tables

version 1.1, October 2021