Swiss Federal Institute for Forest, Snow and Landscape Research WSL

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Edition: Fri 22.11., 17:00
Avalanche Bulletin

We have developed a method for the automated classification of bat echolocation calls to species. This allows us to analyze their habitat requirements.

Kleiner Abendsegler. Bild: Martin Obrist, WSL
Leisler's bat (Nyctalus leisleri). Photo: Martin Obrist, WSL

Man strongly influences environmental conditions and habitats for bats. Until the last decade of the past century bat populations were severely affected by these activities. Consequently, many species are listed as endangered or vulnerable, despite the fact that all bat species are protected by law in Switzerland. Present counts at roosts indicate a slow recovery of populations of some species. However, for many species we lack knowledge about their roosting and their nocturnal foraging habits hampers investigating their  habitat requirements. This complicates the definitions of protection measures. Science is challenged.

Distribution and habitat requirements of native bats

Scientists at WSL have developed a method for the automated classification of bat echolocation calls to species. This allows now to investigate the habitat requirements bioacoustically and analyze the data with GIS tools. The classification tool has been successfully employed in several additional projects.

Make bat calls visible

Bats echolocate inaudible to humans in the ultrasound range. Whoever wants to localize bats acoustically, needs technical equipment that allows for this kind of observation:

BATLOGGER - a Swiss high-end bat detector

Der BATLOGGER, ein Aufnahmegerät für Fledermausrufe.
The BATLOGGER is a recording system for ultrasound bat echolocation calls.

The BATLOGGER is a recording system for ultrasound bat echolocation calls. It helps considerably in observing bats and identify species. Apart from the acoustic data, each recording also stores additional information like location (GPS) and temperature.

Using BATLOGGERs quickly generates large amounts of recordings. Storing these data consistently is important but also laborious. To alleviate these problems, WSL has programmed the following software:

Batscope

BatScope allows to import recordings from BATLOGGERs (and other devices), the structured storage of these data in projects and recording events, visual control of the recordings (spectrograms), and the automated recognition of the calling bat species! When analyzing and verifying the classified acoustic recording, a source of reference signals for acoustic comparison and presenting additional information is very helpful. Relevant references and further information on the species are already built into the BatScope 4 programme.

Relevant publication:

Video: The Batlogger in use (German)

Mit dem BATLOGGER können Fledermausforscher die für den Menschen unhörbaren Ultraschallrufe von Fledermäusen in Echtzeit aufnehmen, dank integriertem GPS-System mit präzisen Ortsangaben verbinden und mit der an der WSL entwickelten Software BATSCOPE den Arten zuordnen. So lernen die Forscher die Jagdgewohnheiten von Fledermausarten besser kennen – eine wichtige Voraussetzung, um gefährdete Arten besser schützen zu können.

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