Bats: a Key for Saving Biodiversity

Project location: Italy, Abruzzo
Project start date: January 2002 - Project end date: December 2003
Project number: 2001-03
Beneficiary: Centro Studi Ecologici Appenninici

Echolocation calls

 Flying bats emit sequences of ultrasonic calls for echolocation, i.e. for navigation and prey identification. Such calls are generally inaudible, but the researchers use special devices, called time-expansion bat detectors, to transfom ultrasounds into audible signals. Time expansion 'slows down' calls 10 times: once expanded, signals sound like the ones which can be listened to on this web page. By means of a special software package, time-expanded calls may be analysed for species identification.


When flying, the barbastelle (Barbastella barbastellus) often alternates between two different call structures, and the time-expanded signals sound like a peculiar 'chip-chop'.

The brown long-eared bat (Plecotus auritus) emits faint calls to approach its favourite prey, the tympanate moths (sensitive to bat ultrasonic calls), without alerting them. When the bat is very close to the moth, it stops echolocating and relies on passive listening to capture its prey: to detect even the faintest noise produced by the insect, these bats have very long ears. Because calls from long-eared bats are so faint, researchers often need to stay close to the bat to get good-quality recordings.

Centro Studi Ecologici Appenninici
The official research organism of the Abruzzo National Park
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