The rusty numbat, the desert bandicoot, the broad-faced potoroo and the crescent nailtail wallaby. What do these native Australian mammals have in common? They have all been wiped out by feral cats.

But the list doesn’t end there. At least 20 other mammal extinctions can be directly contributed to feral cats and the furry killing machines have plenty of other species on their hit list. Feral cats prey on more than 300 different native species. This includes many types of lizards and birds, as well as icons like the greater bilby feeling the pressure of being targeted by feral cats. 

Right now, according to the latest figures, there are at least two million feral cats in Australia and they can be found across 99.98 per cent of the country’s land mass. Every week each of these furry hitmen take out between five to 20 native animals. That means, using the most conservative estimates, if we multiply two million by five, we get at least 10 million native animals killed by feral cats every week. Or 1.4 million natives killed per day, or 511 million per year.

Somehow it becomes worse though. In addition to the direct predation, feral cats spread diseases which can affect wildlife and humans alike.

What are we doing?

In 2015 the Australian Government set the target of culling two million feral cats by 2020. In June 2019, the Australian Government released the Threatened Species Strategy Year Three Progress Report. The report contained highlights from between 2015 and 2018 and said feral cat control has occurred across 18 million hectares and approximately 844,000 feral cats had been culled – coming up just short of the one million target for the time period.

Other highlights from the report included: emergency baiting which prevented the extinction of the central rock-rat, volunteers with the Sporting Shooters’ Association of Australia helping to translocate western quolls to the Flinders Ranges, and Western Australian farmers defending the last numbat stronghold from feral cats.

There are lots of ways the cull has been conducted, but arguably the cutest example has been Dottie, the feral cat detector dog. In Kosciusko National Park, Dottie has helped remove 92 feral cats and 139 foxes, sniffing them out and allowing her handler to humanely remove them from the critically endangered mountain pygmy-possum habitat.

“It is great to see such a wide range of community members doing their part to manage the threat of feral cats,” said Threatened Species Commissioner Dr Sally Box.

“The collective efforts by shooters, hunters, farmers, Indigenous rangers and conservation organisations is helping to protect our remarkable wildlife.”

Indigenous hunters and bilbies

One of Australia’s most vulnerable species is the bilby. Bilbies were once found across most of Australia but now wild bilbies are mostly limited to remote areas in the Northern Territory and Western Australia. Despite the harsh Outback conditions that the last of the bilbies now call home, feral cats are still encroaching on them. There is nationwide recovery programs, but in the bush bilbies have a powerful ally in the form of Aboriginal hunters, who have proved themselves more than capable of handling the persistent feral cats.

As reported by the ABC, Aboriginal rangers have been effectively using fire management and cat hunting skills to help maintain bilby populations in the desert. Tasking Aboriginal rangers with handling the feral cats has so far been a success, especially given the remoteness of the area and allowing the rangers to do meaningful work that they are unparalleled at and that no one else is willing or able to do. Continued investment will be needed to realise the full power of utilising some of the best hunters in the bush though.

Bilby populations have also been re-introduced to different parts of Australia and fences are used to ward off feral cats. However, it’s also important to keep a strong wild bilby population for the sake of the species because it means the bilbies will keep their untamed behaviours and instincts, making them more resilient to predators.

The KI solution

At the other end of the country, Kangaroo Island in South Australia has been battling feral cats its own way. After finishing up their initial phase of research, the Kangaroo Island Natural Resource Management team have moved onto the second stage of their overall feral cat strategy – elimination.

This means getting rid of as many feral cats as possible from the Dudley Peninsula on the eastern side of the island. They will then erect a 3km feral cat-proof fence, dividing Dudley from the rest of the island. The aim will be to continue eliminating feral cats and turning Dudley into a cat-free, safe haven for native species. The fence will extend some distance into the water, so feral cats can’t even attempt swimming  to invade the Dudley secure zone.

“We’ll then be able to take what we’ve learned from Dudley and apply it to the rest of the island,” said Ross Evans from the Kangaroo Island Natural Recourses Management Board.

“We’ve managed to cull hundreds of feral cats so far using grooming traps.”

Ross said grooming traps have proved to be quite effective and function by spraying a poisonous gel onto passing feral cats. Later when the feral cats groom themselves, they ingest the poisons and are killed.

The Kangaroo Island authorities aren’t stopping at just feral cats though,  they want to get rid of all cats. By 2030 the island plans to be entirely cat-free, including outlawing domestically owned cats. The council has already put in place some of the most stringent cat ownership rules in Australia and eventually residents will not be allowed to own cats as pets. Although any currently living pet cat will be allowed to live out its days peacefully. That is a state we hope many more of our native species will be able to savour in the future as well.

Conclusion

Critics of feral cat culling say the process is ineffective because after the initial cull, feral cats will simply repopulate the area. But this is why Kangaroo Island and many other places are culling in conjunction with establishing safe havens for natives. This key part of the plan gives native species a fighting chance to re-establish themselves and maybe adapt to living with their new predators. 

Tackling the problem of feral cats is not easy. They are an evolved killing machine that just so happens to be perfectly suited to Australian conditions and preying on many native species that didn’t have the opportunity to evolve any defences.

Fortunately, we have a number of ways to combat them and the best path forward seems to be a combination of them all. By utilising Indigenous rangers, sniffer dogs, baiting, ground shooting, fencing and policy changes, we might just yet win the battle against feral cats. And hopefully we do, because the survival of our native species looks likely to depend on it.