Aerial baiting and wild dog mortality in south-eastern Australia

Abstract

<p><b>Context:</b> Wild dogs, including dingoes and dingo cross-breeds, are vertebrate pests when they cause financial losses and emotional costs by harming livestock or pets, threaten human safety or endanger native fauna. Tools for lethal management of these animals currently include aerial baiting with poisoned baits. In New South Wales (NSW), Australia, aerial baiting was previously permitted at a rate of 40 baits km^-1 but a maximum rate of 10 baits km^-1 was subsequently prescribed by the Australian Pesticides and Veterinary Medicines Authority. The efficacy of these baiting rates has not been quantified in eastern Australia, undermining the value of the policy and rendering adaptive management efforts difficult, at best.</p> <p><b>Aim:</b> To quantify the mortality rate of wild dogs exposed to aerial baiting at historic and currently approved rates, i.e. 40 baits per kilometre and 10 baits per kilometre, respectively.</p> <p><b>Methods:</b> Wild dog mortality rates were measured at sites in mesic north-eastern NSW, where aerial baiting was applied to control wild dogs and contrasted with sites and individuals where no baiting was undertaken. In total, 132 wild dogs were trapped and fitted with GPS-VHF telemetry collars before annual aerial baiting programs. Collars were used to locate animals after aerial baiting and to determine the fates of individuals.</p> <p><b>Key results:</b> 90.6% of collared wild dogs exposed to aerial baiting at 40 baits km^-1 died, whereas only 55.3% of those exposed to 10 baits km^-1 died (Welsh's <i>t</i> = 4.478, <i>P</i> = 0.004, v = 6.95). All wild dogs that were not exposed to toxic baits survived during the same periods.</p> <p><b>Conclusion:</b> Managers using aerial baiting to maximise wild dog mortality in mesic south-eastern Australia should use 40 baits km^-1 rather than 10 baits km^-1.</p> <p><b>Implications:</b> Wild dog population reduction for mitigation of livestock and faunal predation requires the application of efficacious control. The currently prescribed maximum aerial baiting rate of 10 baits km^-1 is inadequate for controlling wild dog populations in mesic forest environments in NSW.</p>