A meta-analysis of disturbance caused by drones on nesting birds

Abstract

The use of drones for monitoring nesting birds is rapidly increasing given their affordability and efficiency in bird detection and quantification across habitats. Reports of disturbance caused by drones on different bird species have been mixed, with no consensus on the degree to which different factors affect disturbance responses. Given the lack of systematic assessments of disturbance from drones on nesting birds, we conducted a formal meta-analysis to quantify the degree of disturbance caused by multi-rotor drones on nesting birds, with a particular focus on the effects of altitude of flights and species nesting traits. Seventeen studies met our criteria for inclusion in the analysis, from which we extracted 31 effect sizes in the form of log-odds ratio. Drones showed a small disturbance effect (-1.54; 95% CI: -2.83, -0.26) on nesting birds overall, but heterogeneity was large. Drone flights > 50 m showed no evidence of disturbance on nesting birds. Conversely, flights at lower altitudes (≤ 50 m) showed stronger evidence of disturbance effects, with the largest odds of disturbance observed on ground solitary and non-ground solitary nesters. Only ground colonial nesters showed no evidence of disturbance regardless of the drone altitude. We conclude that the use of drones can be an efficient and safe means of surveying nesting birds if altitude and nesting traits are considered in survey protocols.

Keywords

• bird disturbance
• drone altitude
• drones
• effect size
• meta-analysis
• nesting birds
• nesting traits
• small uncrewed aircraft systems (suas)
• unmanned aerial vehicles (uavs)