Bat calls

The kind of sound made by a bat can help in identifying the species you are observing.

Species Rep. rate Rhythm Tone quality Duration FM/CF Tune to
Natterer 30 very irregular crumpled cellophane 2 ms FM 45kHz
Daubenton 16 regular flat click 2 - 4 ms FM 45kHz
Whiskered / Brandts 12 regular dull click 3 - 5 ms FM 45kHz
Pipistrelle 9 quite regular chink 4 - 6 ms Hockeystick 39, 45, 55kHz
Serotine 5 very irregular warble 10 - 15 ms CF 28 kHz
Noctule 4 irregular two distinct 8ms & 20 ms CF 23 kHz
The table above is a rough guide only, as the characteristics of a bat call are strongly affected by its environment.  A bat flying in the open doesn't need to repeat so quickly, and can use a longer duration call.  Calls with a duration less than about 4ms are too short to have a clear pitch and are heard instead as some kind of click; so Pips and Noctules have a clear pitch to their call while Natterers,  Daubentons, Whiskered/Brandts and Long-eared are generally click-like with only occasional calls being long enough to have a clear pitch.
It is hoped soon to provide a range of recordings of bats made by our members, using all three detector types.  If you can provide good (i.e. typical ) recordings particularly for bats/detectors not already listed, please contact me via the dbg mailing list.
Please note it is important to record as much detail as possible of the conditions - weather, surroundings, equipment used and settings, and particularly if using a heterodyne detector the frequency to which it is set.

Recordings of bat calls

Heterodyne

Frequency division

Time Expansion (X20)

You may download the files for your own use by right-clicking on the links below

Heterodyne Frequency division Time expansion
Pipistrelle (pip. pip.) 1M Pipistrelle (pip. pip.) 1.2M Ciel Pipistrelle (pip. pip.) 933k
  Pip. Pygmaeus 429k  
Noctule 1.2M Noctule 343k Noctule 1147k
Daubenton's bat 344k   Daubenton's bat 1507k
Thanks to Philip Briggs and Jules Agate of the Bat Conservation Trust and Ciel Electronique for providing the above files and permission to provide them for non-profit use.
BCT members can access the BCT bat call library where you will find a much wider range of recorded calls.
Bristol's Batlab has time expansion recordings of all the british bats courtesy of Dr. Stuart Parsons.