Aerial shooting is unlikely to cause dispersal or consistent changes in the movements of feral pigs (Sus scrofa)

Context Aerial shooting is an important tool for managing feral pig damage to agricultural and biodiversity assets because it can rapidly reduce population densities over large areas. It should also be valuable for reducing host population densities in the event of an emergency animal disease incursion. However, recent tracking studies have not alleviated concerns that the intense disturbance caused by aerial shooting might cause pigs to disperse from target areas. Aims We investigated the responses of feral pigs to nine aerial shooting operations conducted at five large and divergent sites in south-eastern Australia. Methods We fitted 71 pigs with GPS tracking collars and monitored changes in their behaviour following exposure to aerial shooting operations that lasted between 1 and 11 days. Repeated exposure of some individuals provided 105 distinct samples. We examined the following three key traits: the location and size of activity ranges, daily activity and movement rates, and daily activity cycles. Key results We found inconsistent results between sexes and among operations. However, only one pig left the target area after shooting began. This pig did not return. Conclusions The fine-scale behaviour of pigs subjected to aerial shooting is likely to vary because of a complex interplay of social, environmental, and operational factors. Behaviour changes observed in this study were unlikely to cause the dispersal of feral pigs or their impacts. Implications Given our results, and those of previous studies, we believe that aerial shooting should continue to be used as a key method for managing feral pig populations and should also be considered for emergency animal disease response operations.