Bats use echolocation to navigate and hunt, but they also make calls for communication. When a bat is hunting, the proces of catching an insect becomes visible by a so called feeding buzz. Examples of feeding buzzes can be found on the Feeding buzzes page. Calls used for communication can be found on the Social calls page.

The echolocation of bats are a great way to identify bat species, because the calls of each species has it's own specifications. The shape of the call, the peak frequency of the call, the start and end frequency of the call, the call length and the inter-pulse interval can all be important indicators to determine the species you are dealing with. Two great guides for bat identification are "Bat Calls of Britain and Europe" edited by Jon Russ and "Acoustic Ecology of Europan Bats" by Michel Barataud.

Unfortunately, the Echo Meter Touch 2, the device used to make most recordings in this database, occasionally seems to have a little "blind spot" between 50 kHz and 60 kHz, creating a little gap in the sonograms and thus slicing calls around that frequency.

Different shapes

Examples

Common noctule (Nyctalus noctula)

Peak frequency often around 20 kHz  -  most often qCF calls, sometimes alternated with FM-qCF calls  -  a relatively long inter-pulse interval  -  chip-chop sound

Date of recording: 2024-06-07          Recorded by: Timo Boer          Audio file: 912080 

Serotine bat (Eptesicus serotinus)

Peak frequency often around 25 kHz  -  most often FM-qCF calls, but qCF possible  -  tapdancer sound

Date of recording: 2024-06-03          Recorded by: Nanieke van den Berg          Audio file: 912083 

Nathusius pipistrelle (Pipistrellus nathusii)

Peak frequency often around 40 kHz  or below  -  FM-qCF or qCF calls

Date of recording: 2024-05-30          Recorded by: Rianne Bunschoten          Audio file: 912086 

Common pipistrelle (Pipistrellus pipistrellus)

Peak frequency often around 45 kHz  -  most often FM-qCF calls, but qCF possible

Date of recording: 2024-05-23          Recorded by: Romee Bleijenberg          Audio file: 912090 

Soprano pipistrelle (Pipistrellus pygmaeus)

Peak frequency often around 55 kHz  -  most often FM-qCF calls, but qCF possible

Pond bat (Myotis dasycneme)

Peak frequency often around 35 to 40 kHz  -  high start and low end frequency  -  can produce calls with relatively long call length  -  rattle sound

Daubenton's bat (Myotis daubentonii)

Peak frequency often around 45 to 50 kHz  -  high start and low end frequency  -  short call length -  rattle sound

Brown long-eared bat (Plecotus auritus)

Peak frequency often between 20 - 30 kHz  -  FM calls  -  calls contain harmonics  - quiet crackling sound

Deviations

Bats leaving their roost

Directly at emergence from the roost, echolocation calls are typically short in duration and elevated in frequency and are not typical of free-flying bats (Newson, 2024).

Common noctule leaving it's roost:

Date of recording: 2024-04-28          Recorded by: Dennis Rademaker          Audio file: 920109 

Serotine bat leaving it's roost:

Date of recording: 2024-05-19          Recorded by: Sander Boersma          Audio file: 912051 

Brown long-eared bat leaving it's roost:

Date of recording: 2024-07-13          Recorded by: Boaz van Die          Audio file: 921381 

Common pipistrelle leaving it's roost:

Date of recording: 2024-06-17          Recorded by: Sarah Mahie, Boaz van Die          Audio file: 914381 

Modified echolocation calls

Examples of modified echolocation calls are very rare and so far previous literature written about these calls have not been able to determine the context behind such emissions. They may be communicative, at least to some degree (Middleton et al., 2020).

Hooked echolocation calls of the common pipistrelle:

Hooked echolocation calls of the Nathusius' pipistrelle:

Hooked echolocation calls of the common noctule:

Date of recordings: 2024-08-28          Recorded by: Fabienne Schwab         Audio files:     930849, 930846, 930844, 930842

Not to be confused with the social calls shaped like walking sticks of the pond bat and the Daubenton's bat. And, perhaps, there is also some similarity to the rare social calls of the serotine bat emitted while in flight that can appear as arches.

Social calls of the Daubenton's bat:

Social calls of the pond bat:

Date of recording: 2024-06-06          Recorded by: Anice Hut          Audio file: 911253 

Social calls of the serotine bat:

Date of recording: 2024-07-24          Recorded by: Charlotte Serrarens          Audio file: 923069 

All recordings are licensed under the following Creative Commons Attribution-NonCommercial-NoDerivs 4.0 license and in courtesy of Sarah Mahie.
All sonograms are screenshots of the recordings imported in the ultrasound analysis software BatExplorer 2.2 (Elekon, Switzerland). 

Bibliography:

- Jon Russ (2021). Bat Calls of Britain and Europe: a Guide to Species Identification. Pelagic Publishing. 

- Michel Barataud (2020). Acoustic Ecology of European Bats. Species Identification, Study of their Habitats and Foraging Behaviour (Anya Cockle-Betian, trans.). Second edition. Inventaires & biodiversité series. Biotope - Muséum national d'Hostoire naturelle.

- Neil Middleton, Andrew Froud and Keith French (2022). Social Calls of the Bats of Britain and Ireland (second edition). Pelagic Publishing.

- Stuart Newson (2024). https://www.linkedin.com/posts/stuart-newson