AURITA: an affordable, autonomous recording device for acoustic monitoring of audible and ultrasonic frequencies

Passive acoustic monitoring can be used for many purposes including biodiversity and habitat assessments and studying the ecology of populations, communities and soundscapes. As such, acoustic recording devices are essential data collection tools for bioacousticians and soundscape ecologists. Currently available commercial options are typically expensive and limited to recording either ultrasonic or audible frequencies. Here, we present the AURITA (Audible and Ultrasonic Recording In TAndem) for the autonomous collection of both audible and ultrasonic acoustic data. This self-contained, modular unit combines the Solo, an open-source, Raspberry-Pi-based recorder and a commercially available bat recorder, the Peersonic RPA2, enabling it to capture sounds from 60 Hz to 192 kHz in WAV format. The configuration presented costs ~£350 (excluding memory cards and batteries) to produce and can be maintained and repaired in the field. Two nine-week field tests involving 12 AURITA units were conducted in 2016 and 2017 and confirmed their reliability, resulting in 34,093 h of audible data and 551 h of ultrasonic data; all units were retrieved successfully and intact. The AURITA proved to be reliable in the field and produced high-quality acoustic data, making it ideal for simultaneous monitoring in both audible and ultrasonic frequencies over continuous periods of time.