Miniaturization eliminates detectable impacts of drones on bat activity

Abstract

Unoccupied aerial vehicles (UAVs or drones) are becoming valuable tools in ecological research, as they offer a safer, cheaper and quieter alternative to large aircraft and may be more accurate than conventional methods (Hodgson et al., 2018;Scholten et al., 2019).Additionally, the increasing clarity of airspace regulations on UAV activity in many regions has lifted restrictions and simplified UAV use for wildlife science (Chabot & Bird, 2015;Gonzalez et al., 2016).However, wildlife has had adverse reactions to UAV presence

Towards the fully automated monitoring of ecological communities

“…Nevertheless, it is timely to (i) better quantify these impacts to avoid the generation of biased and unstandardised data; and (ii) aim to minimise these impacts to prevent animal stress. Ways to mitigate these impacts include the development of new unmanned aircraft systems, such as miniaturised drones and blimp‐like aerostats, which eliminate noise disturbance to wildlife (Adams et al, 2020 ; Kuhlmann et al, 2022 ). When such devices are not available, disturbances can be avoided by using greater camera resolutions and obtaining the necessary permits to increase flying height (Scobie & Hugenholtz, 2016 ).…”

Drone exploration of bat echolocation: A UAV‐borne multimicrophone array to study bat echolocation

“…Compared to previous reports, we use a much greater distance between the UAV and the microphones (August & Moore, 2019;Ednie et al, 2021;Fu et al, 2018;Michez et al, 2021), which reduces the noise substantially and very likely also the behavioral impact of the UAV considerably. Previous studies report avoidance behavior and a clear reduction in bat activity in the presence of UAVs with no reports of the recorded foraging that we observe for all recorded species (Ednie et al, 2021;Fu et al, 2018;Kuhlmann et al, 2022). Furthermore, we are relatively stationary during the actual recording, that is, we move the UAV to the desired location and remain there for the duration of the recording, and we return to this spot throughout the whole recording night with minor modifications to the specific altitude.…”

“…Furthermore, we are relatively stationary during the actual recording, that is, we move the UAV to the desired location and remain there for the duration of the recording, and we return to this spot throughout the whole recording night with minor modifications to the specific altitude. This recording method may facilitate habituation by the bats to a much greater degree than the recording methods described in previous studies, that is, moving UAV with the microphone directly attached or suspended a short distance away (Ednie et al, 2021 ; Fu et al, 2018 ; Kloepper & Kinniry, 2018 ; Kuhlmann et al, 2022 ). While this strategy works very well for our purposes, it may not be applicable to surveys if the purpose is to investigate bat activity in as large an area as possible and other mitigation measures may be more appropriate.…”

“…Noise is generally measured on a relative scale with uncalibrated equipment and not with any noteworthy frequency distinction. Reports of the behavioral effect of the UAVs show a reduction in bat activity when UAVs are flown (Ednie et al, 2021 ; Kuhlmann et al, 2022 ), but that the impact can be reduced by using smaller drones (Kuhlmann et al, 2022 ). There are no reports of natural foraging behavior recorded with any of the UAV setups.…”

Selective foraging behavior of seabirds in small‐scale slicks

“…We used a quiet, white-colored micro drone (249 g) at its maximum permitted altitude (120 m), thereby minimizing potential impacts or bias in observations during surveys (Kuhlmann et al 2022). UAVs provide a bird's eye, rather than oblique, view on seabird movement and underlying flows (Lieber et al 2021) and thus provide a suitable tool to quantify slick interactions.…”