Testing a key assumption of using drones as frightening devices: Do birds perceive drones as risky?

Abstract

Wildlife managers have recently suggested the use of unmanned aircraft systems or drones as nonlethal hazing tools to deter birds from areas of human-wildlife conflict. However, it remains unclear if birds perceive common drone platforms as threatening. Based on field studies assessing behavioral and physiological responses, it is generally assumed that birds perceive less risk from drones than from predators. However, studies controlling for multiple confounding effects have not been conducted. Our goal was to establish the degree to which the perception of risk by birds would vary between common drone platforms relative to a predator model when flown at different approach types. We evaluated the behavioral responses of individual Red-winged Blackbirds (Agelaius phoeniceus) to 3 drone platforms: a predator model, a fixed-wing resembling an airplane, and a multirotor, approaching either head-on or overhead. Blackbirds became alert earlier (by 13.7 s), alarm-called more frequently (by a factor of 12), returned to forage later (by a factor of 4.7), and increased vigilance (by a factor of 1.3) in response to the predator model compared with the multirotor. Blackbirds also perceived the fixed-wing as riskier than the multirotor, but less risky than the predator model. Overhead approaches mostly failed to elicit flight in blackbirds across all platform types, and no blackbirds took flight in response to the multirotor at either overhead or head-on approaches. Our findings demonstrate that birds perceived drones with predatory characteristics as riskier than common drone models (i.e. fixed-wing and multirotor platforms). We recommend that drones be modified with additional stimuli to increase perceived risk when used as frightening devices, but avoided if used for wildlife monitoring.

Using drones to reduce human disturbance while monitoring breeding status of an endangered raptor

“…Secondly, concerning behaviors, adult Chaco Eagles flew away in all cases when performing traditional monitoring but barely did it when a drone flew over the nest. The use of drones to monitor birds´nests has resulted in different behaviors across literature (Brisson-Curadeau et al, 2017;Egan et al, 2020;Junda et al, 2016;Lyons et al, 2017;Potapov et al, 2013;R€ ummler et al, 2016; 21) 1 (0) 7 ( 7) 23 ( 14) 3 (0) Flight 34 (20) 1 (0) 7 ( 7) 23 ( 13) 3 (0) Withdraw 34 ( 23) 1 (0) 7 ( 7) 23 ( 16) 3 (0)…”

“…Secondly, concerning behaviors, adult Chaco Eagles flew away in all cases when performing traditional monitoring but barely did it when a drone flew over the nest. The use of drones to monitor birds´ nests has resulted in different behaviors across literature (Brisson‐Curadeau et al., 2017; Egan et al., 2020; Junda et al., 2016; Lyons et al., 2017; Potapov et al., 2013; Rümmler et al., 2016; Vas et al., 2015). No attack to the climber or to drones was registered in any case, contrary with the stronger reactions against disturbance that some raptors tend to exhibit (Junda et al., 2016; Lyons et al., 2017; Morrison et al., 2006).…”

“…Nevertheless, drones may affect indi-viduals´behavior and reduce their reproductive output, thereby altering species' fitness and biasing research results (Borrelle & Fletcher, 2017;Grenzd€ orffer, 2013). Evidence for drone disturbance to birds has been already found (Brisson-Curadeau et al, 2017;Dulava et al, 2015;Egan et al, 2020;Lyons et al, 2017;R€ ummler et al, 2016), also in the case of raptors (Junda et al, 2016;Lyons et al, 2017). Raptors are particularly suitable species for breeding monitoring using drones because they build large open-nests on top of tall trees or at the slopes of cliffs (Newton, 1979), which usually are easy to access with these aerial vehicles.…”

Bird damage to sunflower: international situation and prospects

“…French regulations do not allow this use: an operator must remain within range. The shape of these UAVs can imitate predators (Wang et al, 2017;Egan et al, 2020).…”

Nesting Common Eiders (Somateria mollissima) show little behavioral response to fixed-wing drone surveys

“…However, this is an area of growing research. Several studies have anecdotally evaluated behavior, but it has not been until recent years that controlled studies focused on behavior have been conducted (Barnas et al 2018b;Barr et al 2020;Egan et al 2020). A review of behavioral studies by Mulero-Pázmány et al (2017) concluded that there are many factors that impact behavioral responses of wildlife which include species, life history characteristics, drone platform characteristics, altitude, and flight approaches (at angles vs. directly at animals).…”