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

Citation

Egan, Conor C.; Blackwell, Bradley F.; Fernandez-Juricic, Esteban; Klug, Page E. (2020), Data from: Testing a key assumption of using drones as frightening devices: do birds perceive drones as risky?, Dryad, Dataset, https://doi.org/10.5061/dryad.brv15dv66

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 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.

Methods

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

Usage Notes

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
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:


1.) Eganetal_ArchivedDataset.csv contains the following variables:

Treatment = Combination of platform type and approach type that each bird was exposed to during trials
Platform = Platform type that each bird was exposed to during trials (i.e, predator model, fixed-wing, multirotor)
Trajectory = Approach type that each bird was exposed to during trials (i.e., head-on or overhead)
Type = Fixed-wing and Predator model coded as "1", Multirotor coded as "0"
Latency = Latency to resume foraging (seconds)
LogLatency = Log transformed latency to resume foraging (seconds)
Speed = Drone speed per trial (meters per second)
Deprived = Length of time birds were food deprived prior to trials (hours)
Wind Origin = Direction wind originated from while being measured
Wind = Wind origin combined to reflect headwind, downwind, or crosswind
OriginCat = Direction wind orginated from, convered to #s for coding
Windspeed = Windspeed (kilometers per hour)
Light = Ambient light intensity (µmol m-2 s-1)
Temperature = Temperature (Celsius)
PUP1 = Proportion of time (30 s) birds spent head-up versus head-down prior to drone approaches
PUP2 = Proportion of time (30 s) birds spent head-up versus head-down following drone approaches
UPdiff = The difference between PUP1 and PUP2
Approach = Approach time (seconds) of the drone between launch and the time it passed above the enclosure
Sound = Ambient sound intensity (decibels) during trials
Alerttime = Individual alert time (seconds) per trial
LogAlert = Log transformed invidual alert time (seconds) per trial
Flush = Did the bird flush the perch in response to drone flights? 1 = Yes, 0 = No
Call = Did the bird alarm call in response to drone flights? 1 = Yes, 0 = No
Flight = Individual flight-initiation time (seconds) per trial


2.) Eganetal_MixedModelData.csv contains the following variables:

ID = Identifiation number assigned to each individua bird
Treatment = Combination of platform type and approach type that each bird was exposed to during trials
Platform = Platform type that each bird was exposed to during trials (i.e, predator model, fixed-wing, multirotor)
Trajectory = Approach type that each bird was exposed to during trials (i.e., head-on or overhead)
Speed = Drone speed per trial (kilometers per hour)
Light = Ambient light intensity (µmol m-2 s-1)
Time = Time of measurement relative to drone flight. Before = before drone flight, After = after drone flight
Vigilance = Proportion of time (30 s) birds spent head-up versus head-down

Funding

National Wildlife Research Center, Award: USDA-APHIS-WS NWRC; #7438-0020-CA; QA-2731

Federal Aviation Administration, Award: Interagency Agreement DTFACT-14-X-400007

Animal and Plant Health Inspection Service, Award: USDA-APHIS-WS NWRC; #7438-0020-CA; QA-2731