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Domestic, feral, wild, or stray cats are the same species (Felus catus). Introduced into New Zealand by European settlers in the mid 19th century, in 2011 there were are an estimated 1.419 million domestic cats in New Zealand. An unknown but significant number have become wild or feral, being highly successful top-level predators. It has only been relatively recently that the impact of cats on wildlife has become better understood. 

Feral cats live independently of humans and breed in the wild, although they also breed with unwanted domestic cats. 

Contents of cat stomach included 32 lizards and geckos
Contents of cat stomach included 32 lizards and geckos

Where are they found?

Along all braided river ecosystems in New Zealand.

Why are they a problem?

The impact on critically endangered black-fronted terns is staggering (Image: Colin O\'Donnell/ DOC)
The impact on critically endangered black-fronted terns is staggering (Image: Colin O\’Donnell/ DOC)
Being ‘generalist’ mammals, cats are fast breeders and highly adaptable to a wide range of climates and habitats. Once established in an area, they are next to impossible to eradicate.
  • Opportunistic hunters of endemic birds, reptiles, and invertebrates, as well as introduced pest mammals including rats, mice, and rabbits
  • No matter how well fed, a cat’s natural instinct is to hunt
  • The presence of cats on braided rivers can lead birds to abandon nests and chicks
  • Cat ownership per person in New Zealand is one of the highest in the world, leading to an emotive argument that favours cats over rare and endangered native wildlife
  • The SPCA’s policy of ‘trap-neuter-return’ returns undomesticated cats to the wild colonies. As these colonies also uptake abandoned un-neutered cats, the policy does not reduce cat numbers or commensurate bird kill rates. This single neutered male cat wiped an entire colony of fairy terns, in spite of the colony being inside a protected sanctuary
  • Feral cats are estimated to be responsible for the extinction of 6 endemic bird species and over 70 localised subspecies, as well as depleting the populations of bird and lizard species
  • Studies in the US show that up to 4 billion (not a misprint) birds are killed annually in that country alone by cats

Conservation activities

When other pest mammals such as rats, mice, and rabbits are controlled, cats specifically target birds, lizards, and larger invertebrates. When rabbit haemorrhagic disease (RCD) was illegally introduced into New Zealand, feral cats switched from preying on rabbits to preying on native fauna, including the black stilt, leading DOC to undergo a trapping programme for cats and other predators.

  • Cat traps are used on several braided rivers during the breeding season

Information for cat owner/lovers

  • Don’t feed stray cats. This is misplaced sympathy. A well-fed stray, feral, or wild cat –has more energy to hunt native species, will breed more successfully, and carries multiple diseases known to infect your cat and humans

If you own a cat:

  • Have your cat neutered or spayed so they can’t produce unwanted kittens
  • Keep your cat well fed and have moving toys for it to play with, so it is less inclined to chase birds, etc
  • Keep your cat indoors during the day. Otago University research has shown that in New Zealand, domestic cats prefer to hunt birds during the mornings, lizards in the afternoons, and rats and mice at night. However, near braided rivers, domestic cats have been filmed stalking braided river bird chicks at night. One domestic cat can result in an entire colony of breeding birds abandoning a nesting site.
  • Don’t dump unwanted kittens and cats – either give them to the SPCA or ask a vet to put them down humanely
  • Collaring you cats with bells will reduce their kill rate by 50%
  • Microchip your cat to ensure it is not inadvertently destroyed if caught in a live trap
  • Consider replacing it with a different type of pet when it dies

More information & research