Feral cats are killing millions of birds each year. Should they be culled?

Cats have long held a special place in the life of ex-breeder and conservationist, Julie Boyd, providing colour and companionship, as well as being keen rodent hunters. On her sprawling rural New Zealand property in the upper North Island town of Kaipara Flats, the cats roam free.

“I have an elderly cat- Padme – who is 17-18 [years old], she doesn’t catch anything”, Boyd notes, “I also have three other desexed cats. Ariki likes to hang out at the hay barn where he knows there will be mice taking up residence now autumn has arrived.”

With 1.4 million domestic cats, Aotearoa has one of the highest cat ownership rates in the world – at least 40% of households have at least one. Feral cats are also reported to be in the millions.

But estimates from one conservation group, Forest and Bird, suggest New Zealand’s pet cats alone kill at least 1.12 million native birds a year, in some cases helping propel them towards extinction. In one early case, a lighthouse keeper’s cat is said to have annihilated an entire species, the flightless Lyall’s wren, on Stephens Island at the end of the 19th century.

Like many New Zealand cat owners who believe feral rather than domestic cats are the problem however, Boyd insists her pets mainly hunt mice and rats rather than birds.

And cats have been left off Predator Free 2050, the government’s ambitious plan to rid the island nation of its pests, including stoats, ferrets, weasels, rats and possums. Now, there are growing calls from environmental groups for cats to be part of the plan.

Boyd, who has recently helped restore two acres of wetland bordering her property, doesn’t believe Predator Free 2050 or cat regulation will solve the problem.

“Cats might be seen as the easiest predator to eliminate, but cats fulfil an important role for many humans. Companion cats are usually seen as part of the family. They also kill significant numbers of rodents.”

An apex predator on an island of birds

Tamsin Orr-Walker, chair of the Kea Conservation Trust, says if New Zealand has any chance of extinguishing introduced predators in the next 30 years, it needs to have a serious discussion about cats.

“The problem relates specifically to our relationship with cats. I’m not anti-cat. There are so many people who have cats as pets. But a lot of people can’t see their pet as a hunter, which all cats are,” she says.

Orr-Walker wants cats to be considered in the Predator Free 2050 plan, as well as the introduction of tighter regulation on domestic cats.

She cites Australia – which requires owners to register their cats after three months, and in certain parts of the country, limits ownership to two cats per household as well as enforcing cat curfews at night – as a useful example of what form tighter regulation could take.

“That is a conversation we need to have that cats can be at least as damaging as dogs are to our wildlife. We have addressed the issue of dog impact on wildlife with very extensive legislation in our dog control act, yet there is nothing stopping us from regulating cats.”

Orr-Walker is currently working through evidence of feral cats attacking adult kea. New Zealand’s highly endangered alpine parrot has gone from being a pesky bird known for its mischievous nature to a nationally endangered species hiding in the high mountains, declining to an estimated population of 3,000-7,000.

As a place formerly free of land-based mammals aside from a few species of bat, New Zealand’s native birds, insects, lizards and bats are defenceless against such predators as cats. In one infamous case in 2010 one feral cat mauled 102 short-tailed bats, who were roosting in beech trees on Mt Ruapehu, over the course of a week.

In both Wellington and Kaikōura, there are reports of free-roaming domestic cats decimating colonies of native banded dotterels. There are also fears that recent conservation success stories, such as the return of the endangered tīeke to Wellington, could be sabotaged by free-roaming cats.

It’s proved a sensitive subject to bridge, with cat owners feeling demonised and conservationists being smeared as cat haters. Tensions reached a crescendo in 2013, when philanthropist and ex-politician Gareth Morgan unveiled efforts to eradicate cats under the Cats to Go campaign, causing widespread consternation – including opposition from the then prime minister – while Morgan received hate mail and even death threats.

After the furore of that campaign, there is still no policy on domestic cats. Jessi Morgan, chief executive officer of Predator Free New Zealand Trust and daughter of Gareth, understands domestic cats play an important role in society, but argues that without regulation conservation work is being undermined.

“The tools for controlling cats are limited, especially if you are near populated areas, because you can’t run the risk of killing a well-loved moggie,” she says.

“We advocate for responsible cat ownership, a bit around educating people on the impact cats have on native species in New Zealand … We think it’s important for people to keep cats at home, to microchip them and de-sex them.”

Though her cats have been desexed, Boyd says she won’t be keeping her cats inside or supporting other regulations.

“I don’t believe that licensing cats or owners is the answer. Licensing cat owners means good cat owners will be penalised and will be subsidising the others, without ever reaching the goal of keeping cats from predating native fauna.”

This article by Findlay Buchanan was first published by The Guardian on 7 April 2022. Lead Image: New Zealand’s pet cats are estimated to be responsible for killing at least 1.12 million native birds every year. Photograph: New Zealand Transition/Getty Images.

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