Data from: Testing a key assumption of using drones as frightening devices: do birds perceive drones as risky?

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 to 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.