Exposure to a robotic falcon induces consistent collective escape responses of two avian species and can trigger massive and persistent displacements of birds

Avian collective behaviour, arising from associations of similarly behaving individuals in groups, can create conflicts with human activities, resulting in safety hazards, health issues and economic losses. Bird flocks can be dispersed or prevented from gathering at specific locations through a variety of methods. The effectiveness of these methods is often low and prone to habituation. Recently, the use of remote-controlled, raptor-like robotic predators has been proposed as a deterrent. Habituation of birds should not affect its effectiveness because it takes advantage of the innate escape response of prey species to their predator. We used a robotic peregrine falcon (RobotFalcon hereafter RF) to assess the consistency of the escape response of two flockforming species: feral pigeons Columba livia (about 500 individuals) and black-headed gulls Chroicocephalus ridibundus (about 8000 individuals). We repeatedly exposed flocks to the RF and analysed the consistency of their collective behaviour, habituation and effectiveness of this method using video-recordings. For gulls, we monitored daily flying activity using marine radar during, before and after the exposure days, to investigate long-lasting effects of RF exposure. The RF induced consistent collective escape response in both species, involving the same collective behaviours performed by avian preys against real avian predators. There was no evidence of habituation, but deterrence effectiveness was higher for gulls than pigeons, with evidence of long-lasting effects. The RF is a valuable tool that can be used to deter birds where human-wildlife conflict may arise. Its effectiveness of deterrence could vary among species and depend on resources used by the species.