The effect of cat baiting on foraging and antipredator behaviour of the northern quoll in the Pilbara, Western Australia

There is an urgent need to develop approaches to mitigating the impact of predation by cats on Australian wildlife. In arid and semi-arid Australia, broad-scale cat baiting programs have been shown to effectively reduce cat populations and, as a result, lead to an increase in the abundance of small native mammals. Understanding how native wildlife respond to a reduction in the abundance of cats, and/or the predation pressure they exert, is critical to evaluating the cost-effectiveness of cat management programs.

We have made use of a 4-year feral cat baiting program, being undertaken by the Western Australian Department of Biodiversity, Conservation and Attractions, on Yarraloola station in the Pilbara region of Western Australia (2016–2019), in order to understand the effects of a reduction in cat abundance on the foraging behaviour of the EPBC Act-listed (Endangered) northern quoll (Dasyurus hallucatus). We analysed quoll survey data to assess differences in the daily patterns of quoll activity between the baited property and an unbaited property nearby. We also conducted a 'givingup density' (GUD) experiment to understand how perceived predation risk varies between the baited and unbaited properties and in relation to habitat features.

Despite earlier published evidence that the cat baiting program has led to an increase in the abundance of the northern quoll between 2016 and 2019, we found no clear evidence that cat baiting led to a shift in the daily patterns of quoll activity, nor perceived predation risk. However, there was clear evidence that broad habitat types (mesa vs. riverine), and microhabitat within these (open vs. sheltered), affect perceived predation risk. There was a greater propensity to visit feeding trays in the riverine habitat, and within sheltered areas. There was evidence that more food was consumed from feeding trays in sheltered areas.

Our results highlight the importance of both broad- and fine-scale habitat features on predation risk of the northern quoll, and other small mammals. They are consistent with the notion that habitat management, to maintain and enhance the structural complexity and density of understorey vegetation (e.g. by reducing grazing by exotic herbivores, reducing fire frequency, extent and intensity) can help to mitigate the impacts of cats on small mammals. Further research is required to evaluate the feasibility, and cost-effectiveness, of such an approach in the Pilbara.