Feral cat (Felis catus) prey size and selectivity in north‐eastern Australia: implications for mammal conservation

Abstract

AbstractThe domestic cat Felis catus is distributed worldwide and has had a long historical relationship with humans. In some regions, such as Australia, it has become feral and a significant predator of native wildlife. A key component of quantifying and managing the conservation threat of introduced predators is an understanding of exactly what size and taxa of prey species are consumed, and whether there is a high degree of selectivity in the diet. A total of 169 cat stomachs were collected from north‐eastern Australia, and their contents examined in relation to prey size, the body size of cats and selectivity using Jacob's index. I found that F. catus contains a large amount of prey per cat (∼200 g), mammals are the dominant prey item by mass, and feral cats predation was selective of small mammals (<10 g, 50–100 g), and reptiles and birds in the 10–50 g and 50–100 g size ranges, respectively. Reptiles form a large component of the diet compared with other regions in the world. Many mammals in northern Australia that are declining are within the size range that is highly selected by feral cats; the relationship between smaller cat size in the tropics and smaller prey size has correspondence to the fact that the declining mammals in this region are smaller than those that went extinct in southern Australia. There is an urgent need to find a conservation solution to reducing feral cat predation on wildlife, and this should include landscape scale reduction in fire extent and frequency, and removal of cattle in key sites, in order to maintain ground cover, thus reducing the predation success of feral cats.