Journal Article

Measuring behavioral responses of sea turtles, saltwater crocodiles, and crested terns to drone disturbance to define ethical operating thresholds

Whiting, Scott, Douglas, Ryan, Raith, Andrew, Guinea, Michael, Bevan, Elizabeth, Tucker, Tony

2018

Overview

Drones are being increasingly used in innovative ways to enhance environmental research and conservation. Despite their widespread use for wildlife studies, there are few scientifically justified guidelines that provide minimum distances at which wildlife can be approached to minimize visual and auditory disturbance. These distances are essential to ensure that behavioral and survey data have no observer bias and form the basis of requirements for animal ethics and scientific permit approvals. In the present study, we documented the behaviors of three species of sea turtle (green turtles, Chelonia mydas, flatback turtles, Natator depressus, hawksbill turtles, Eretmochelys imbricata), saltwater crocodiles (Crocodylus porosus), and crested terns (Thalasseus bergii) in response to a small commercially available (1.4 kg) multirotor drone flown in Northern Territory and Western Australia. Sea turtles in nearshore waters off nesting beaches or in foraging habitats exhibited no evasive behaviors (e.g. rapid diving) in response to the drone at or above 20-30 m altitude, and at or above 10 m altitude for juvenile green and hawksbill turtles foraging on shallow, algae-covered reefs. Adult female flatback sea turtles were not deterred by drones flying forward or stationary at 10 m altitude when crawling up the beach to nest or digging a body pit or egg chamber. In contrast, flyovers elicited a range of behaviors from crocodiles, including minor, lateral head movements, fleeing, or complete submergence when a drone was present below 50 m altitude. Similarly, a colony of crested terns resting on a sand-bank displayed disturbance behaviors (e.g. flight response) when a drone was flown below 60 m altitude. The current study demonstrates a variety of behavioral disturbance thresholds for diverse species and should be considered when establishing operating conditions for drones in behavioral and conservation studies.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Algae / Alligators and Crocodiles - physiology / Altitude / Animal behavior / Animal welfare / Animals / Aquatic reptiles / Australia / Beaches / Behavior / Behavior, Animal - physiology / Biodiversity / Biology / Biology and Life Sciences / Birds / Caretta caretta / Chelonia mydas / Cheloniidae / Conservation / Crocodiles / Crocodylia / Crocodylus porosus / Disturbance / Diving / Drones / Earth Sciences / Ecology and Environmental Sciences / Environmental aspects / Environmental protection / Environmental research / Eretmochelys imbricata / Ethical aspects / Ethics / Flight / Flight behavior / Flyovers / Foraging habitats / Head movement / Human-environment interactions / Medical ethics / Medicine and Health Sciences / Natator depressus / National parks / Nesting / Reptiles & amphibians / Saline water / Saltwater crocodile / Science programs / Sea turtles / Sensory integration / Species diversity / Studies / Submergence / Terns / Thresholds / Turtles - physiology / Unmanned aerial vehicles / Vehicles / Wildlife / Wildlife conservation / Wildlife habitats / Wildlife management / Zoology