Bats use ultrasound to navigate and forage in the darkness of the night. Humans have developed devices capable of recording and transforming these inaudible sounds to audible ones and even allow us to identify the species that emits them. There is a great diversity of devices for this purpose, with a variety of options and settings, different formats and prices. This is allowing not only researchers to obtain detectors, but any bat enthusiast.
The generated sound files can be passed into software specifically designed to allow the identification of different bat species. Thanks to bioacoustics, chiropters can be studied in a less invasive way and let us observe their natural behaviors, to better understand how they communicate with each other, how they forage, etc.
Learning to interpret bats ultrasounds requires practice and participation in workshops such as the European Alpine Bat Detector Workshop (EABDW) can be very useful. The EABDW is a workshop designed for both professionals and amateurs interested in gaining experience in recording bat activity with several ultrasonic detectors, and improve their skills in the subsequent analysis with various specific software; share experiences and expand knowledge. Two of our members, Laura and Àngel Torrent, attended the third EABDW workshop that took place in Askim, a town south of Oslo, in Norway in August this year.
They recorded species which are rare in Spain, but common in Norway, such as the parti-coloured bat (Vespertilio murinus) or the noctule bat (Nyctalus noctula) and were also able to see and record the European bat that lives furthest north, the northern bat (Eptesicus nilssoni).
During the workshop, Laura and Àngel attended several lectures, which ranged from the distribution of the Norwegian bat species, the comparison of hand-made detectors of different prices, types of microphones and their functionalities, the use of zero-crossing method and learning how to distinguish types of social calls. All this thanks to local experts such as Leif Gjerde and Arnold Andreasson, as well as international speakers such as Chris Corben and Neil Middleton.
A few undertook a trip to the north of the country to look for known breeding colonies of three species, the northern bat (E. nilssoni), the whiskered bat (Myotis mystacinus) and the Brandt’s bat (Myotis brandtii), located closer to the arctic circle. For this, they traveled more than 1000 km by car crossing mountain areas, infinite fjords dotted with waterfalls and even crossed the sea by ferry.
This trip has been a very instructive and inspiring experience for Laura and Àngel and they encourage all acoustic geeks to attend workshops of this style to learn and share their knowledge (The next EABDW conference will be in Scotland in 2021!).
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