Population dynamics, diet and aspects of the biology of feral cats and foxes in arid South Australia

摘要

Average cat and fox densities at Roxby Downs, in northern South Australia, of 0.8 and 0.6 km–2 respectively, determined through spotlight counts over a 10-year period, probably considerably underestimate true densities. Peak rabbit populations coincided with high fox numbers, which probably suppressed cat densities. Cat abundance peaked when fox numbers were low but rabbit numbers were relatively high.nnWhen abundant, rabbits were the principal prey of both cats and foxes. Declines in rabbits numbers coincided with dramatic declines in fox numbers. By contrast, declines in cat populations were less marked, presumably because they could more effectively switch to hunting a wide range of native vertebrates. Sand-dwelling lizards, house mice and common small passerines were the most abundant non-rabbit, vertebrate prey taken by cats. We estimate that annual cat predation accounted for approximately 700 reptiles, 150 birds and 50 native mammals per square kilometre, whereas foxes consumed on average 290 reptiles per square kilometre and few native mammals and birds in the Roxby Downs region each year.