Koalas showed limited behavioural response and no physiological response to drones.

Drones have become a popular conservation tool especially when monitoring cryptic species or species inhabiting locations difficult to access. We developed a non-invasive methodology to measure heart rate in koalas (Phascolarctos cinereus) using a Fitbit and investigated the behavioural (vigilance behaviour) and physiological (heart rate and breathing rate) responses of captive koalas to drones. We showed for the first time that heart rate values in koalas can be accurately obtained with a Fitbit. Koalas responded to a drone flight conducted 15 m above their heads with a short-term increase in vigilance, but no change in heart rate or breathing rate. Our results suggest that drones may not have long-term detrimental effects on koalas’ fitness or energy demands and adds to the growing literature investigating animals’ responses to drones to help develop best practices for drone monitoring.