The little big killers…. cats
The predation of native species by cats comes up in almost every On the Brink column. They wreak havoc among native species already under pressure from habitat loss, sometimes pushing them to extinction. Today there are there are approximately 3.8 million domestic cats and up to 6.3 million feral cats in Australia.
Cats were introduced to Australia with the First Fleet and soon there were feral cats in Australia. Australian species had not co-evolved with cats and for such an efficient predator they were easy prey. Before long, feral cats had spread throughout Australia, often well in advance of the European settlers. However, the cats did not have it all their own way. The indigenous inhabitants started hunting the cats as a food source. Unfortunately, as Aboriginal Australians died from European diseases, forced onto missions and reserves, or made to work on stations, there was nothing to keep the cat numbers in check. Today traditional hunting of feral cats only occurs in the Nyirripi and Kiwirrkurra communities.
Another introduced pest species, the rabbit, proved itself to be a real bonus for feral cats. The large numbers of rabbits allowed the feral cat population to explode. It would be great if feral cats only ate rabbits, but they are opportunistic hunters and will kill any creature they can eat. A decline in rabbit numbers due to myxomatosis, calicivirus, or drought forces the cats to seek out other prey; inevitably native species.
Feral cats can grow to be big…very big. They weigh up to nine kilograms and can have a nose to tail tip length of over 90cm. It takes a lot of prey for them to grow to this size and then sustain them. A feral cat in the bush will eat 791 mammals, birds, reptiles and frogs each year and 371 invertebrates. Female cats can have two litters of kittens a year so the competition for a territory is fierce; another reason why they are so big. The sightings of panthers roaming the bush are most likely very big feral cats. The density of the feral cat population varies considerably with the availability of prey. The average density of feral cats is about one cat per four square kilometres.
Unless they are kept in an enclosure or inside domestic cats also exact a toll on wildlife. Just because they are domestic cats does not mean they have lost their instinct to hunt. Domestic cats will hunt. Most at risk are small ground dwelling creatures: skinks and lizards, ground frequenting birds such as crested pigeons and red-rumped parrots, and small native mammals such as antechinus and bandicoots. While not so at risk, small birds will avoid a cat’s territory, depriving them of habitat. Most municipalities require a cat to be confined to its owner’s property and have a have a cat curfew requiring cats to be inside after dark. Both of these requirements are often ignored by cat owners.
At present I have blue wrens building their annual nest in a wormwood, a pair of striated pardalotes are checking out a nesting box, two species of skinks are doing skinky stuff, the crested pigeons are starting to display and court and various rosellas are looking at their nesting box. None of these things would be happening in my garden if there was a cat on the scene.
