Feral cat, Rangitata River valley
Image: DOC

Feral cats

Introduction

Feral cats have a major impact on native birds, bats, lizards, wētā and other insects

Feral cats are one of the most ferocious predators in our ecosystem. They feed on rabbits, birds and bird eggs, rats, hares, bats, lizards, mice, wētā and other insects.

Studies have shown feral cats have a devastating effect on native species. Here are some examples.

  • In 2020, a feral cat caught in Canterbury had 17 skinks in its stomach.
  • In 2010, a feral cat in Ohakune killed 107 bats/pekapeka in just one week.
  • From 2019 to 2021, feral cats caused the death of 20% of monitored kea in Arthur's Pass.

Description

We have three cat populations in New Zealand.

  1. Domestic/house cats cared for by and living with humans.
  2. Stray cats partly cared for by humans.
  3. Feral cats living independently and not relying on humans for survival.

Although all three cat populations pose a threat, feral cats are a high risk to our native taonga.

Feral cats have the same appearance as common, short-haired house cats. They can grow much larger than house cats, measuring up to a metre long, including the tail. Male feral cats captured in the South Island high country averaged a weight of 3.75 kg and the heaviest male weighed 7 kg. Feral cats tend to be fitter and faster than house cats.

Where they're found

Feral cats are widespread in New Zealand. Scientists tracked a feral cat in the South Island high country that covered almost 6 km in one night. Feral cats live in a variety of habitats, including coastal areas, farmland, forests, riverbeds, sub-alpine environments and on islands.

We have no accurate estimate of the feral cat population in New Zealand.

Why they're here

Europeans used cats to control rats and mice aboard sea vessels. After Europeans arrived in 1769, cats gradually spread across the country. Settlers noted the first feral cat population 50 years later.

The threat

Impacts on our native wildlife

Feral cats are significant predators of the endangered black stilt/kakī in the Mackenzie Basin. Only 30% of young birds released through the captive rearing programme are surviving to become adults. This is due to predation by feral cats, stoats and ferrets.

Endangered black stilt/kakī, wrybill/ngutu pare and black-fronted tern/tarapiroheare are heavily impacted by feral cats in South Island braided riverbeds.

Research has shown feral cats killed juvenile and adult kea in an area between Arthur’s Pass and Lewis Pass on the eastern side of the main divide. A 2019-2021 study showed up to 20% of monitored kea were killed by feral cats.

Grand and Otago skink populations are at critically low levels in Central Otago, in part due to cat predation, along with stoats, ferrets and weasels.

Both feral and domestic cats are known to hunt native bats/pekapeka.

In the 1980s, all kākāpō were removed from Stewart Island/Rakiura to stop predation by cats. 

The rare Southern New Zealand dotterel, which breeds on Stewart Island/Rakiura, has suffered significant population loss due to feral cats.

On subantarctic Auckland Island, feral cats have contributed to the global or local extinction of more than 29 bird species. Evidence suggests only 13 of the 38 native bird species remain on Auckland Island.

Toxoplasmosis

Cats can transmit the parasite Toxoplasma gondii to sheep, humans and native wildlife. When cat feces containing T. gondii get into water runoff, it can cause the deaths of both Hector's dolphins and the critically endangered Māui dolphins.

Toxoplasmosis and Hector’s and Māui dolphin

A feral cat preys on a banded dotterel at its nest

DOC’s work

We have a legislated mandate to manage feral cats on public conservation land to protect native wildlife. We control feral cats at many sites around New Zealand, including to protect:

  • kiwi in Northland
  • shore birds at coastal breeding sites
  • black stilt/kakī and other braided river birds in the Mackenzie basin
  • orange-fronted parakeet/kākāriki karaka in Canterbury
  • Otago and grand skinks in the Central Otago drylands.

We sometimes manage feral cats on land owned by other agencies, organisations or individuals. This is in the interest of conserving threatened species.

We’ve cleared feral cats from several offshore islands, including Raoul Island and Rangitoto Island. This allows native species to flourish and means we can reintroduce other native species.

Control techniques

We use poisoning, trapping and shooting to control feral cats. When employing lethal methods, we use efficient and humane best-practice techniques. We follow the Animal Welfare Act 1999.

Challenges

Controlling feral cats is an ongoing battle because they reinvade controlled areas over time.

There are no centralised rules or legislative tools, or agency for management of cats, in the same way there are for dogs. We’re in favour of national cat management legislation, as outlined in the draft National Cat Management Strategy. We see this as an important measure to decrease the impact of cats on native wildlife.

We don’t support the "trap, desex, release" approach to managing stray cats. This is because cats are predatory animals that continue to pose a threat to wildlife.

Domestic cats

We’re respectful of cat owners and their rights to keep companion animals.

Although the management of domestic and stray cats is outside our mandate, we support responsible cat ownership.

How you can help

House cats hunt native wildlife, including birds, bats, wētā and other insects.

If you own a cat, you can help by:

  • desexing and microchipping your cat
  • keeping your cat indoors or contained inside a 'catio', especially at night
  • putting your cat in a cattery when you go on holiday
  • never taking them onto public conservation land.

Pets on conservation land

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