Aerial baiting and wild dog mortality in south-eastern Australia

Abstract ContextWild 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. AimTo 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. MethodsWild 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. Key results90.6% 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 t=4.478, P=0.004, v=6.95). All wild dogs that were not exposed to toxic baits survived during the same periods. ConclusionManagers 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. ImplicationsWild 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.

Aerially deployed baits in the northern rangelands of Western Australia are available to wild dogs

Context Aerial baiting using fixed-wing aircraft is an effective method of bait delivery for wild-dog control in remote locations. However, aerial baiting may result in loss of baits to positions that are inaccessible to wild dogs. Attempts, by landholders, to address such bait loss through compensatory baiting may increase baiting costs and potential risks to non-target species. Aims To assess bait drift under standard baiting conditions. To assess the availability of aerially deployed baits to wild dogs across several commonly baited landforms in the northern rangelands of Western Australia. Methods We determined drift characteristics of baits deployed under standard fixed-wing baiting conditions. We then determined the availability of aerially deployed baits by deploying baits with embedded radio-transmitters across four commonly baited landforms (riparian vegetation, tussock grassland, gorges and breakaways). We then visually assessed the availability of relocated baits (as ‘high’, ‘moderate’ or ‘low’). Key results Under standard fixed-wing baiting conditions, on average, baits fell 100.9 m forward, and 8.3 m laterally, from the point-of-release. Across all landforms, most baits (91.8%) were highly available, with a further 7.0% falling into the moderate category and 1.2% in the low category. There were significant differences in bait availability among landforms, with the proportion of moderate-low availability baits greatest in gorges and lowest on tussock grassland. Conclusions Within the northern rangelands of Western Australia, bait wastage owing to deployment in inaccessible locations is minimal. Implications Compensatory baiting for lost baits is unnecessary and increases costs to land managers.

A strategic approach to mitigating the impacts of wild canids: proposed activities of the Invasive Animals Cooperative Research Centre

Wild canids (wild dogs and European red foxes) cause substantial losses to Australian livestock industries and environmental values. Both species are actively managed as pests to livestock production. Contemporaneously, the dingo proportion of the wild dog population, being considered native, is protected in areas designated for wildlife conservation. Wild dogs particularly affect sheep and goat production because of the behavioural responses of domestic sheep and goats to attack, and the flexible hunting tactics of wild dogs. Predation of calves, although less common, is now more economically important because of recent changes in commodity prices. Although sometimes affecting lambing and kidding rates, foxes cause fewer problems to livestock producers but have substantial impacts on environmental values, affecting the survival of small to medium-sized native fauna and affecting plant biodiversity by spreading weeds. Canid management in Australia relies heavily on the use of compound 1080-poisoned baits that can be applied aerially or by ground. Exclusion fencing, trapping, shooting, livestock-guarding animals and predator calling with shooting are also used. The new Invasive Animals Cooperative Research Centre has 40 partners representing private and public land managers, universities, and training, research and development organisations. One of the major objectives of the new IACRC is to apply a strategic approach in order to reduce the impacts of wild canids on agricultural and environmental values in Australia by 10%. In this paper, the impacts, ecology and management of wild canids in Australia are briefly reviewed and the first cooperative projects that will address IACRC objectives for improving wild dog management are outlined.