A low-cost technique for radio-tracking wildlife using a small standard unmanned aerial vehicle

Recent advances in using unmanned aerial vehicles (UAVs) to study wildlife offer promise and may improve data collection efficiency, and small UAVs, such as multirotor platforms, are suitable for this task because they are easy to deploy, can fly over terrain that is difficult to access on foot, and can be programmed to follow specific trajectories. The objective of our study was to determine whether a small UAV could be outfitted with a radio receiver to pick up signals from radio-transmitters worn by small forest birds (Catharus bicknelli and C. ustulatus). We compared radio-monitoring using an UAV and a ground-based vehicle. The detection of over 50% of the tagged birds in the 50 m altitude flights is indicative of the real potential of the concept. This is supported by a signal strength significantly stronger and more constant than ground-based signals. The signal receptor experienced no significant interference from the UAV electronics, thus enabling a "clean" set of detections from the birds. Based on these preliminary results, we conclude that UAVs can yield useable data from animals wearing light-weight transmitters. Radio-tracking birds with UAVs presents strong potential for applications in all types of forest stands, or even in the radio-tracking of multiple species or taxa.