Site fidelity trumps disturbance: aerial shooting does not cause surviving fallow deer (Dama dama) to disperse

Abstract

Context Aerial shooting is an important tool for managing the economic and environmental impacts of widespread wild fallow deer populations in eastern Australia and could be crucial for mounting an effective response to an emergency animal disease incursion. However, there is a concern that the disturbance caused by aerial shooting could cause infected animals to disperse, thereby transmitting pathogens to previously uninfected areas. Aims We sought to describe the nature and extent of spatial behavioural changes in fallow deer exposed to aerial shooting to: (1) assess the risk that aerial shooting poses to disease spread, and (2) better understand how aerial shooting can contribute to routine deer management programs. Methods We contrasted movement rates, activity range areas, and daily activity patterns of 48 GPS-collared fallow deer before, during and after exposure to aerial shooting at three sites in New South Wales. Key results No collared deer left its pre-shoot activity range area during shooting or within 30 days after shooting finished. Observed behaviour changes included increased daily and hourly distance travelled by female deer during and after shooting, increased activity range areas for female deer after shooting, and increased nocturnal activity in female and male deer during shooting. However, observed changes were minor, temporary, localised, and variable among sites. Conclusions Collared deer showed strong site fidelity despite repeated intense disturbance and substantial population reductions. We found no evidence to support concerns that aerial shooting poses a hazard of disease spread. Implications Aerial shooting should be retained as a key control tool for managing wild fallow deer populations in Australia, including for reducing disease host population densities in the event of an emergency animal disease incursion.