Diet of the feral cat, Felis catus, in central Australian grassland habitats during population cycles of its principal prey

Abstract

Foraging theory predicts that animals should forage so as to maximize their net rate of energy gain or to minimize their risk of starvation. In situations where prey numbers fluctuate dramatically, theory predicts further that foragers will eat 'optimal' prey when it is abundant but expand their diet to include other prey types when the optimal prey is scarce; this is the alternative prey hypothesis. Here, we test this prediction by analyzing the diet of a mammalian predator, the feral house cat Felis catus, during periods of scarcity and abundance of the long-haired rat Rattus villosissimus. We also investigate whether the body condition of feral cats differs during different stages of the prey population cycle. Feral cats were shot during culling operations in semi-arid grassland habitats in central Queensland, Australia, and the stomach contents later identified. We found that the body condition of feral cats did not differ between phases of the prey population cycle, but the diets of cats culled when long-haired rats were scarce were significantly more diverse than when this rodent was abundant. Rats comprised about 80 % of cats' diet by volume and frequency of occurrence when they were present, whereas birds, reptiles and invertebrates comprised the bulk of the diet when rats were not available. We conclude that, whilst feral cats are often thought to be specialist predators, they may be better considered as facultative specialists that will shift their diet in predictable ways in response to changes in the abundance of primary prey.

Prey selection and dietary flexibility of three species of mammalian predator during an irruption of non-cyclic prey

“…Indeed, more extensive prey shifts have been observed previously in the diets of the red fox and dingo in arid and semi-arid regions, compared to that of the feral cat [ 35 ]. The feral cat, however, exhibits moderate dietary flexibility in these systems, including, for example, more reptiles and invertebrates in its diet when fewer small mammals are available [ 34 – 36 ]. These findings stand in contrast to our own; while the feral cat did display some dietary variability and diversity (by including reptiles and invertebrates as dietary components during the early bust stage and birds during the boom and bust stages), it did not significantly vary its diet between the high and low stages of the irruption cycle.…”

Introduced cats Felis catus eating a continental fauna: inventory and traits of Australian mammal species killed

“…In Australian landscapes, cats are generally opportunistic predators that hunt most effectively in open habitats and prefer to take live prey smaller than their own body size (McGregor et al 2015, Leahy et al 2016, Read et al 2018. Cats have a highly flexible diet, and although they may selectively hunt certain prey species, they can adapt readily to changing prey availability by prey-switching, and hence may prey on a wide range of mammal species present in their range (Yip et al 2014, Dickman & Newsome 2015. Most (78%) Australian mammals have a mean adult body mass of less than 3 kg and are generally accessible to cats when they are active.…”

Resource pulses affect prey selection and reduce dietary diversity of dingoes in arid Australia

“…) and other predators such as raptors (McDonald & Pavey ) and feral cats Felis catus (Pettigrew , Yip et al. ), to alter their diet and exploit hyper‐abundant prey.…”

“…Note the logarithmic scale of the x-axis. & Pavey 2014) and feral cats Felis catus (Pettigrew 1993, Yip et al 2015, to alter their diet and exploit hyper-abundant prey.…”