The fox in the box: acoustic deterrent and simulated predator disturbance to reduce problematic bird accumulations

Abstract

Context Collisions between birds and aircraft (bird strikes) are a serious threat to aviation safety and these negative human–wildlife interactions are predicted to increase. As the wider spatial use of landscapes by birds can affect aviation safety (e.g. location of foraging and roosting sites), there is a clear need to implement effective management strategies at sites adjacent to airfields to reduce ingress of avian taxa across airfield boundaries. Aims In the present study, we assessed the efficacy of both an acoustic deterrent (sonic net) and a visual simulated predator effigy, in the form of a fox-shaped model, to disturb and reduce bird accumulations on: (1) agricultural foraging sites; (2) an active airfield; and (3) problematic roof-top roosts. Methods These non-lethal scare technologies were assessed separately and in combination by using a factorial design. Bird abundances, species richness and behavioural changes were considered. Key results Although the scare technologies did not reduce bird species richness at treated sites, in most cases, a significant reduction in bird abundances was observed. Equally, the number of birds observed to forage or roost was also generally significantly reduced, as was time spent by birds within treated sites. However, the effects of treatments were not universally across species. For example, a reduction in the abundance of gulls tended to be paired with an increase in the number of corvids for foraging sites. Nevertheless, the combined application of the sonic net and fox effigy caused a considerable reduction in foraging bird numbers, whereas singular treatment types appear to work best for roof-top roosts. Data also indicate that the sonic-net technology can be used to deter night-time roosting on an active airfield. Conclusions When taken together, treatments resulted in substantial and often significant reductions in bird abundance, foraging and roosting activity, as well as site residency time. However, treatment efficacy tended to be context and taxon specific. Implications Sonic net and mobile simulated predator effigies represent promising experimental scare technologies. Following further testing, the integration of these technologies into bird management interventions could yield substantial risk reductions for bird strikes, as well as improved non-lethal management of problematic roosting and nesting sites.