A continental-scale analysis of feral cat diet in Australia

Aim Reducing the impacts of feral cats (Felis catus) is a priority for conservation
managers across the globe, and success in achieving this aim requires a
detailed understanding of the species’ ecology across a broad spectrum of climatic
and environmental conditions. We reviewed the diet of the feral cat
across Australia and on Australian territorial islands, seeking to identify biogeographical
patterns in dietary composition and diversity, and use the results
to consider how feral cats may best be managed.
Location Australia and its territorial islands.
Methods Using 49 published and unpublished data sets, we modelled trophic
diversity and the consumption of eight food groups against latitude, longitude,
mean temperature, precipitation, environmental productivity and climate-habitat
regions.
Results We recorded 400 vertebrate species that feral cats feed on or kill in
Australia, including 28 IUCN Red List species. We found evidence of continental-
scale prey-switching from rabbits to small mammals, previously recorded
only at the local scale. The consumption of arthropods, reptiles, rabbits,
rodents and medium-sized native mammals varied with different combinations
of latitude, longitude, mean annual precipitation, temperature and environmental
productivity. The frequency of rodents and dasyurids in cats’ diets
increased as rabbit consumption decreased.
Main conclusions The feral cat is an opportunistic, generalist carnivore that
consumes a diverse suite of vertebrate prey across Australia. It uses a facultative
feeding strategy, feeding mainly on rabbits when they are available, but switching
to other food groups when they are not. Control programmes aimed at
culling rabbits could potentially decrease the availability of a preferred food
source for cats and then lead to greater predation pressure on native mammals.
The interplay between cat diet and prey species diversity at a continental scale
is complex, and thus cat management is likely to be necessary and most effective
at the local landscape level.