Four-legged killers must be stopped

16:00, Jan 22 2013
DANGEROUS: Cats are killing our native birds, says Gareth Morgan.

New Zealand is the last refuge of a huge range of bird species, we are famous for our claim to be clean and green, and some of us have recognised the huge economic benefit, let alone the ecological dividend, from achieving a Predator-Free New Zealand.

But the vision is flawed. Almost half of Kiwi households have a cat (or two), making New Zealanders the world's most prolific cat owners, with a feline population of 1.4 million (not including feral and stray cats). This epidemic is wiping out our native birds. While the cat population is extremely healthy, our bird population is not. 

About 40 per cent  of New Zealand's native land-birds are already extinct, and of all the bird species remaining 37 per cent are endangered.

Cats are a major player in the destruction of native birds, skinks and invertebrates (such as weta). In our cities cats wipe out native birds faster than they can breed. Cats are opportunistic - how much and what they kill depends on the location and the amount of available prey. Yes, cats kill rodents, particularly in areas where native critters have been wiped out. That was one reason we first took them as pets long ago, but this is no excuse in the modern era: nowadays we have rat traps.

Most cats kill. The average cat brings home 13 pieces of prey per year, but this number is literally based on what the cat dragged in. A University of Georgia study put ''kittycams'' on cats and tracked their carnage. The cats brought home only 21 per cent  of what they killed. Half of the time they left their prey to rot and about 30 per cent  of the time they ate it all on the spot. That means the average cat may be killing more than 60 prey items per year.

In short, if you have not seen your cat killing native animals then either you have not seen them, or there are not enough left for them to catch, they have helped kill off the supply.

Before you say it, even well-fed cats kill. In one study, six cats were presented with a live small rat while eating their preferred food. All six cats stopped eating the food, killed the rat, and then resumed eating the food. Belled collars do not totally stop cats killing either, native birds in particular do not associate a ringing bell with danger. And if you manage to find your cat with a still live bird and it escapes, do not kid yourself: its chances of survival are negligible.

New Zealand should be teeming with birds, we should be deafened by their calls every morning. Go to any sanctuary where predators are eliminated and watch the native bird and plant life flourish.

Urban ecological island projects such as  Zealandia in Wellington are little more than a very expensive cat food factory. It would have been miles cheaper for the Wellington Council to control domestic cats.

What do we need to do? Naturally I am not suggesting you go out and knock your favourite furry friend on the head right now. But if we are serious about conservation then we must acknowledge that we are harbouring a natural born killer. At the very least responsible people should consider not replacing it when it dies and meanwhile either keep it indoors or invest in a cat-proof enclosure in the backyard.

Councils need to step up and require that cats are controlled as stringently as dogs; all of them should be registered, chipped and neutered and the owners made responsible for ensuring they do not wander. Parts of Australia have already gone further with curfews and even cat-free zones in sensitive wildlife areas. Councils should have a policy of putting down all trapped cats that are not chipped or registered, just as we do with dogs, and citizens should be encouraged to help by using live-catch traps for cats that wander onto their properties. If some have a right to own cats then others should have a right to protect the wildlife on their property.

Last year I was at a Southland school and a child asked a fantastic question. If the Kiwi died out, what would we call ourselves? The only thing I could think of was ''Pretty bloody useless''.

Gareth Morgan is an economist who has launched a campaign to reduce the cat population. For more, go to


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