Using mobile device built-in microphones to monitor bats: A new opportunity for large-scale participatory science initiatives

Here we present audio data collected in the study titled "Using
mobile device built-in microphones to monitor bats: a new opportunity for
large-scale participatory science initiatives", now accepted for
publication in Biodiversity and Conservation (DOI:
10.1007/s10531-024-02818-9). Citizen science has become a crucial tool in
biodiversity monitoring, often facilitated by the diffusion of mobile
devices, such as smartphones and tablets. High costs of professional
equipment often limit large-scale monitoring, particularly in bat
monitoring programmes based on acoustic surveys. Here we present the
potential of using mobile devices for bat monitoring, allowing for
large-scale, volunteer-based monitoring programmes. We initially compared
mobile devices’ performance with a professional bat detector for recording
low-frequency bat calls. We then conducted a citizen science pilot study
to test the method’s feasibility in a real-world setting, recording
echolocation and social calls of nine European bat species. We found high
similarity in spectrogram quality between calls recorded by mobile devices
and professional bat detectors. However, differences in sound quality and
effectiveness among mobile device brands and models were found. The
citizen science pilot study tested 35 mobile device models, all of which
effectively recorded bats. This study suggests that mobile devices could
be an accessible, no-cost tool for large-scale bat monitoring.
Incorporating mobile devices into existing monitoring networks or creating
new dedicated programmes could not only enhance data collection, but also
boost public knowledge and awareness about bats, ultimately promoting
informed decision-making and better conservation strategies. To facilitate
a comprehensive evaluation of the acoustic data quality achievable through
the described method, we are providing access to all bat recordings
collected via mobile devices during the study. These have been compiled
into the compressed file named "mobile_device_recs.zip". For
those seeking a quicker review, we recommend downloading the
"Appendix_S6_recs.zip" file, which contains selected examples of
echolocation or social calls from the nine bat species recorded during our
research. Spectrograms of these example recordings are displayed in
Appendix S6 of the published study.