Denny, E. A., & Dickman, C. R. (2010). Review of cat ecology and management strategies in Australia. Invasive Animals Cooperative Research Centre, Canberra.
Felis catus, the domestic cat, occurs throughout the Australian mainland as well as on more than 40 islands off the Australian coast. Cats exploit diverse habitats, including deserts, forests, woodlands, grasslands, towns and cities, and occur from sea level to altitudes above
2000 m. The classification
of cats as domestic, stray or feral (Moodie 1995) reflects the varied ecology
of cats and their dichotomous status in — as both a valued pet
species and an introduced feral predator. Australia
Feral cats are carnivorous hunters that depredate animals up to
but more often take prey under 200
g. The feral cat is linked to the early continental
extinctions of up to seven species of mammals. They are also linked to island
and regional extinctions of native mammals and birds and have caused the
failure of reintroduction attempts aimed at re-establishing threatened species.
Today, 35 vulnerable and endangered bird species, 36 mammal species, seven
reptile species and three amphibian species are thought to be adversely
affected by feral cats. Other species are potentially affected by infectious
diseases transmitted by cats. The true environmental and economic impact of
feral cats has not been calculated.
In most Australian states and territories, legislation has been introduced to restrict the reproductive and predation potential of owned domestic cats. Many local government areas have introduced cat-specific legislation, with restrictions including the banning of cats as pets in some communities, compulsory neutering, individual identification, and containment of pet cats.
Predation by feral cats was listed as a Key Threatening Process under the Federal Endangered Species Protection Act 1992 (now incorporated in the Environment Protection and Biodiversity Conservation Act 1999). A Threat Abatement Plan for Predation by Feral Cats was produced in 1999 and amended in 2008 to promote the recovery of vulnerable and endangered native species and threatened ecological communities (Environment Australia 1999 and DEWHA 2008).
The three most common techniques for estimating cat abundance in
are spotlighting, counting tracks, and bait uptake estimates. The accuracy of
spotlighting is dependent upon the density of vegetative cover and cat
behaviour; the accuracy of track counts depends upon where track pads are set
and the competence of the operative in recognising tracks; and most bait uptake
studies provide data on cat activity rather than relative abundance or
All three techniques are best suited to open, dry habitats with low vegetative cover. In wetter, more closed and productive habitats with high vegetative cover, techniques such as remote photography and the analysis of DNA extracted from scats or hairs provide alternatives for estimating abundance or density. Such estimates are a necessary prerequisite for the implementation of control or eradication programs to avoid over- or under-commitment of labour, time and money, and are also necessary to measure the efficacy of management programs.
Techniques for control or eradication
A nationally co-ordinated program of feral cat control across
is not feasible, as it is with other introduced species, and control efforts
are best targeted at protecting threatened species or habitats. All successful
cat eradication programs in Australia
have been conducted on islands or within areas bounded by predator-proof
fencing, and most have required the use of more than one control method.
Successful techniques for the control or eradication of cats on islands have
proved largely impractical on the mainland. Hunting, trapping and shooting are
time and labour intensive and not economically viable over large areas.
Trap-neuter-return is unsuccessful in open populations and not practical over
large areas. The introduction of disease (eg panleucopaenia) is restricted by
the probable impact on owned domestic cats and the low transmission rate
amongst widely dispersed feral cats. Toxins presently registered for cat
baiting may have unacceptable environmental impacts on many habitats. Australia
Research into more felid-specific toxins, cat attracting baits and lures and cat-specific toxin delivery systems may lead to the adoption of poisoning as the most widely used technique for the control or eradication of feral cats.
Management at the regional and local level
Management of feral cats requires reliable data on the density or relative abundance of cats in targeted areas, and analysis of the cost effectiveness and efficacy of the various control measures that may be implemented. At the regional and local level, eradication of cat colonies and the management of resource-rich artificial habitats to discourage colonisation by cats should be an adjunct to any feral cat control program. Implementation of companion animal legislation that requires firmer controls on the owned, domestic cat population is also an important consideration for the longer-term reduction of the feral cat population in
Factors limiting effective management
Although adequate legislation is in place in some jurisdictions, the problems associated with cat control programs in
include: the time, cost and social impacts associated with enforcing companion
animal legislation; the acceptance in some states of cats as pest control agents;
variable cat densities between habitats; relatively low bait acceptance by
feral cats; a lack of programs aimed specifically at stray cat colonies
exploiting highly modified habitats; little data on the impact of cat removal
on populations of introduced rodents and rabbits; and few accurate estimates of
the density or relative abundance of feral cats. Australia
Research is needed to define the most successful methods for gaining public acceptance of the importance of maintaining effective companion animal legislation; estimating densities of cats in various habitats; the cost effectiveness of control techniques including broadscale baiting; assessing the impact of the removal of colony-forming cats in resource-rich artificial habitats on the broader feral cat population; and assessing the impact of cat removal on both native and introduced small mammal populations and the further indirect effects of removal on other components of the biota.