Evaluating the behavioural responses of wildlife and domestic animals to drones: a Tasmanian case study     

Unoccupied aircraft systems (UAS), also known as drones, are an emerging tool for surveying animals (wildlife and domestic) and are rapidly supplanting other survey techniques. However, the behavioural response of animals to drone activities can vary according to the focal species, therefore evaluating comparisons between animals of different species and domesticity are needed. Here we investigated the impacts of drone presence on two large terrestrial mammals from Tasmania, Australia —  Bennett's wallaby  ( Notamacropus rufogriseus ), and Forester kangaroo ( Macropus giganteus tasmaniensis ), and a ground bird, the domestic chicken ( Gallus  gallus domesticus ) — using a commercial quadcopter model: DJI Phantom 4 Pro. We found that Forester kangaroos and Bennett's wallabies started to exhibit noticeable changes in behaviour, including evasion, when the drone motor sound exceeded ~50 decibels (dB) as heard from the ground (at flight altitudes of 30 – 50 m AGL). At lower sound levels (48 dB and below, above 50 m AGL), the macropod response was minimal. The response of domestic chickens to the drone was remarkably similar to that of the  Macropus species, despite the species generally being more susceptible to, and instinctively vigilant against drone-sized aerial predators such as raptors. This study establishes essential baseline information for understanding the limitations of drone operations across species, compares the behavioural responses of wildlife and domestic animals to drone surveys, and demonstrates the viability of these surveys for both groups when disturbance is minimised.