NEWS smallest drone occupied some of the highest frequencies and the mediumsized drone had the lowest frequency range . It was interesting that most of the bats returned after the drone finished flight and powered off , and that different bat species had varying levels of sensitivity to drone flight .
Summary
Some drones have characteristics that are less disturbing to wildlife and are
better suited for wildlife surveys compared to others . For bats , and likely many other animals , smaller and quieter drones minimize the impact of drones on wildlife surveys . Despite this finding , wildlife surveys often require sensors that may be too heavy for miniature drones . With this in mind , we encourage drone users to use the smallest and quietest drone possible within the constraints of their study and make modifications to ensure their drones produce less noise and disturbance to wildlife .
This case study demonstrates that drone miniaturization eliminates any measurable impact of drones on wildlife and therefore produces more accurate and less invasive drone-based acoustic wildlife surveys .
Figure 4 . Larger drone models correlate with a larger decrease in bat activity . The two largest drones ( Phantom and Pro ) caused the largest negative change in bat activity compared to the smallest drone ( Mini ), which produced an equal response in bat activity to the control . Credit : Kayla Kuhlmann .
Grassroots Vol 22 No 1 March 2022 46