Assessing Raspberry Shake and Boom Sensors for Recording African Elephant Acoustic Vocalizations

Abstract

Acoustic sensors are increasingly being used in ecological and conservation research, but the choice of sensor can be fraught with trade-offs. In this work we assess the performance of the Raspberry Shake and Boom (RS&B) sensor package for detecting and monitoring African elephants (Loxodonta africana). This is the first documented test of this particular unit for recording animal behavior; the unit was originally designed for detecting tectonic earthquakes and low frequency (<50 Hz) atmospheric acoustics. During a four day deployment in South Africa we tested five RS&B units for recording acoustic and seismic vocalizations generated by a group of African elephants. Our results highlight a varied degree of success in detecting the signals of interest. The acoustic microphone recorded fundamental frequencies of low-frequency (<50 Hz) harmonic vocalizations that were not clearly recorded by more sensitive instruments, but was not able to record higher frequency harmonics due to the low sampling rate (100 Hz). The geophone was not able to consistently record clear seismic waves generated by vocalizations but was able to record higher harmonics. In addition, seismic signals were detected from footsteps of elephants at <50 m distance. We conclude that the RS&B unit currently shows limited potential as a monitoring tool for African elephants and we propose several future directions and deployment strategies to improve the sensitivity of the sensor package.

Volcano infrasound: progress and future directions

“…Infrasound microphones and associated equipment (digitizers and power supplies) are becoming smaller and lower in cost (e.g., Marcillo et al 2012;Anderson et al 2018b;Lamb et al 2021) and, as a result, more widely used. The continued proliferation of infrasound sensors will result in more observations of varied styles of volcanic activity, which will help to validate existing hypotheses and pose new questions.…”

Airborne Infrasound Makes a Splash

“…Other activity such as colliding ocean waves (the “ocean microbarom”) (Waxler & Gilbert, 2006), wind blowing over mountains (Bedard, 1978; Walterscheid & Hickey, 2005), and severe storms (Goerke & Woodward, 1966) can create long duration signals that comprise much of the Earth's infrasonic background at low frequencies. Regional to local infrasound (and occasionally audible emissions) have been reported from small earthquakes (Johnson et al., 2020; Sylvander et al., 2007), iceberg calving (Richardson et al., 2010), tornadoes (Elbing et al., 2019), thunder (Arechiga et al., 2014; Dessler, 1973), the aurora (Pasko, 2012), and even elephants (O. D. Lamb et al., 2021), see Campus and Christie (2010) for a comprehensive list. Human‐caused events can make infrasound as well.…”

Monitoring of Local Earthquakes in Haiti Using Low-Cost, Citizen-Hosted Seismometers and Regional Broadband Stations

“…RS have been used to complement broadband sensors for monitoring the reduction in global ambient noise following restrictions imposed to contain the propagation Covid-19 (Lecocq et al, 2020). Others are exploring their potential use for studying animal behavior (Lamb et al, 2021). Moreover, the ease-of-use and connectivity of RS make them ideal instruments for promoting seismic risk awareness through proactive citizen involvement, touching on educational and social aspects (Calais et al, 2020;Diaz et al, 2020;Jeddi et al, 2020;Subedi et al, 2020).…”