The bat microphone
Bats —especially the Natterer's Bat and the Brown Long-eared Bat— often visit the North Sea. To gain a better understanding of their presence in wind farms, Rijkswaterstaat installs bat microphones on the TenneT platforms. These microphones record the high-frequency sounds made by the bats.
From the sounds of bats, we can infer their size, flying behavior, environment, and prey type. With the bat microphone, we can gain more insight into the presence and behavior of different bat species in the North Sea.
The bat microphone records sounds in the frequency range of 15 to 100 kHz. Within this frequency, background noises can also be heard, such as sounds from the platform on which the microphone is mounted. Therefore, we are working on a filter to make the bat sounds more audible.
Recording Locations and Data
The bat microphone is installed at four locations: the Offshore Expertise Center in Stellendam, Wind Farm Borssele Platform Alpha, Wind Farm Borssele Platform Beta, and Wind Farm Hollandse Kust Zuid Platform Alpha. Raw recording data is collected at these locations. The corresponding WAV files can be requested from Joris Diehl, Engagement Manager Ecological Sensors at Rijkswaterstaat (joris.diehl@rws.nl).
Users and Applications
The data collected by the bat microphone is used within the Offshore Wind Ecological Programme (Wozep), which conducts research on the ecological impact of offshore wind energy.