Natural born killers: the problem with cats

A feral cat with its prey of a Major Mitchell's cockatoo. (Credit: Lisa Wilson) MANY OF US LOVE CATS. I love cats. But has the time come to break our addiction to them? They have been great companions since their domestication in the Middle East 10,000 years ago, and today they number more than 500 million worldwide. But the partnership is one we need to reconsider.

Australia has the world's worst record for mammal extinctions; 28 species and subspecies, mostly marsupials, have become extinct since Europeans arrived, and many of these extinctions are linked to cats and other introduced species.

Cats are fabulous little predators. They've honed their skills over millions of years and, despite appearing beguilingly fluffy and adorable, they are swift and silent killers.

This we already knew, but a new study from the Smithsonian Institution, and the US Fish and Wildlife Service, has revealed something shocking. It shows that free-ranging pet and feral cats in the USA kill perhaps 2.4 billion birds and 12.3 billion mammals each year, most of which are natives, rather than introduced species such as brown rats.

Cats are major threat to native wildlife

The startling conclusion is that cats are the biggest human-linked cause of death for native animals in the US, with a bigger impact than habitat destruction, pesticides, pollution and collisions with cars - all regarded as more pressing conservation issues.

No such large studies have been made of the impact of cats in Australia. But the Australian Wildlife Conservancy (AWC), which runs private conservation reserves across the nation, released a report in December which estimated the impact of the 5-18 million feral cats on native species such as bilbies and numbats.

Each cat takes 5-30 animals a night, says the AWC, so (using a conservative population estimate of 15 million) they conclude that a minimum of 75 million native animals are killed daily. In a country struggling to conserve its unique fauna, the scale of this figure should not be underestimated.

Across the Tasman in New Zealand it is birds rather than mammals that have suffered, many of them flightless ground-dwellers. There's the lamentable story of the Stephens Island wren, one of only three flightless songbirds ever known. It was discovered by lighthouse keeper David Lyall in 1894, only to be hunted to extinction by his pet cat and a number of others shortly after.

'Cats to Go' campaign

In total, the extinction of nine bird species and the perilous state of 33 others has been linked to cats - and this is in a country where 48 per cent of homes own them, the highest figure globally.

In January, prominent NZ economist and philanthropist Gareth Morgan called on the public to do something to stop the damage. With his 'Cats to Go' campaign he proposes cats are phased out. Feral cats should be euthanased, he says, and people should consider not replacing pets when they die, or keeping them indoors.

Many owners don't believe their lovable kitty is a killer, but a recent study from the University of Georgia, USA, which attached cameras to 60 pets, found almost half were active hunters. It also revealed them eating roadkill, lapping at sewer water and dodging cars - providing other good reasons to keep your cat safe at home.

Removing cats simply won't work in Australia. The government says it isn't feasible to eradicate feral cats on the mainland, meaning that the best hope for some endangered species is that populations will be fostered on cat-free islands, or in fenced enclosures of the kind the AWC creates.

Reducing the kills made by pet cats

It's a different story with pets, though. If you have a cat, there are easy steps you should take to minimise the impact on local wildlife. Keeping it in at night can reduce the kills it makes by half.

Cats should also wear a collar with a bell, or, even better, a sonar beeper that produces high-pitched tones, which doesn't bother cats, but alerts birds to their presence. Neutering stops cats procreating and makes them less likely to roam and hunt.

Of course the cats are blameless - they're just doing what their instincts tell them. Cat owners claim to be animal lovers and, if this is true, they need to step up for our native wildlife. We're proud of our stunning landscapes, but Australia has a shameful record when it comes to conservation.

Most people wouldn't consider letting their dog run free in the neighbourhood, so why is it acceptable for cats? Perhaps it's time to make this cat your last or keep future cats indoors.