Engineering

Ecology

Aerospace engineering

Biology

Flock

Foraging

Wing

Endocrinology

Paleontology

Bird flight

Mathematics

Geography

Environmental science

Geometry

Quadcopter

Flushing

Altitude (triangle)

Disturbance (geology)

Bird Conservation International

Summary Unmanned aerial vehicles (UAVs) are useful tools in ornithological studies. Importantly, though, UAV-caused disturbance has been noted to vary among species. This study evaluated guidelines for UAVs as a tool for researching geese. Twenty-four flocks of foraging geese were approached at an altitude of 50–100 m with a quadcopter UAV and disturbance effects were analysed across different horizontal distances between the UAV and the flocks. Geese were increasingly disturbed when approached by a UAV, with birds showing increased vigilance behaviour within approximately 300 m. Increasing UAV flight altitude as well as increasing take-off distance from the flocks both decreased the risk of bird flocks flushing. In conclusion, when monitoring geese using UAVs, flight altitudes of 100 m and take-off distances of ideally ∼500 m are recommended, to minimise initial disturbance and reducing the risk of birds flushing.

Evaluation of disturbance effect on geese caused by an approaching unmanned aerial vehicle