DOI: 10.5061/dryad.brv15dv66
title: Data from: Testing a key assumption of using drones as frightening devices: do birds perceive drones as risky?

description: 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.
description: See publication for full methods: Conor C. Egan, Bradley F.
 Blackwell, Esteban Fernández-Juricic, Page E. Klug. 2020. Testing a key
 assumption of using drones as frightening devices: do birds perceive
 drones as risky? The Condor: Ornithological Applications
description: We did not include trials where the behavioral response occurred
 during or after a piloting error (e.g., drone crashed or significantly
 deviated from the flight path; n = 7). For<br> vigilance, we only
 considered birds that foraged from the perch a full 30 s. Thus, we omitted
 birds from analysis that did not forage for a full 30 s or perched in a
 manner that was not comparable to other birds (i.e. directly on the food
 tray as opposed to the perch). These values are "NA" in the CSV
 files. We are also missing a single value for ambient sound intensity,
 because the sound recorder was turned off during a single trial.
 Overview description of variables in each data set:
 <br> 1.) Eganetal_ArchivedDataset.csv contains the
 following variables:<br>  <br> Treatment = Combination of
 platform type and approach type that each bird was exposed to during
 trials<br> Platform = Platform type that each bird was exposed to
 during trials (i.e, predator model, fixed-wing, multirotor)<br>
 Trajectory = Approach type that each bird was exposed to during trials
 (i.e., head-on or overhead)<br> Type = Fixed-wing and Predator model
 coded as "1", Multirotor coded as "0"<br>
 Latency = Latency to resume foraging (seconds)<br> LogLatency = Log
 transformed latency to resume foraging (seconds)<br> Speed = Drone
 speed per trial (meters per second)<br> Deprived = Length of time
 birds were food deprived prior to trials (hours)<br> Wind Origin =
 Direction wind originated from while being measured<br> Wind = Wind
 origin combined to reflect headwind, downwind, or crosswind<br>
 OriginCat = Direction wind orginated from, convered to #s for
 coding<br> Windspeed = Windspeed (kilometers per hour)<br>
 Light = Ambient light intensity (µmol m-2 s-1)<br> Temperature =
 Temperature (Celsius)<br> PUP1 = Proportion of time (30 s) birds
 spent head-up versus head-down prior to drone approaches<br> PUP2 =
 Proportion of time (30 s) birds spent head-up versus head-down following
 drone approaches<br> UPdiff = The difference between PUP1 and
 PUP2<br> Approach = Approach time (seconds) of the drone between
 launch and the time it passed above the enclosure<br> Sound =
 Ambient sound intensity (decibels) during trials<br> Alerttime =
 Individual alert time (seconds) per trial<br> LogAlert = Log
 transformed invidual alert time (seconds) per trial<br> Flush = Did
 the bird flush the perch in response to drone flights? 1 = Yes, 0 =
 No<br> Call = Did the bird alarm call in response to drone flights?
 1 = Yes, 0 = No<br> Flight = Individual flight-initiation time
 (seconds) per trial <br> 2.)
 Eganetal_MixedModelData.csv contains the following variables:
 ID = Identifiation number assigned to each individua
 bird<br> Treatment = Combination of platform type and approach type
 that each bird was exposed to during trials<br> Platform = Platform
 type that each bird was exposed to during trials (i.e, predator model,
 fixed-wing, multirotor)<br> Trajectory = Approach type that each
 bird was exposed to during trials (i.e., head-on or overhead)<br>
 Speed = Drone speed per trial (kilometers per hour)<br> Light =
 Ambient light intensity (µmol m-2 s-1)<br> Time = Time of
 measurement relative to drone flight. Before = before drone flight, After
 = after drone flight<br> Vigilance = Proportion of time (30 s) birds
 spent head-up versus head-down