New Zealand has had it with predators. Rats, possums and stoats — which aren't native to the island nation — kill 25 million native birds each year, and also prey on other native species such as lizards. The invasive species carry disease and cost the country about $3.3 billion New Zealand dollars (more than $2.3 billion) annually, according to estimates from the government.

So, their days are numbered. By 2050, New Zealand hopes to be completely predator-free.

“While once the greatest threat to our native wildlife was poaching and deforestation it is now introduced predators,” said Prime Minister John Key in a statement, when announcing the program.

“This is the most ambitious conservation project attempted anywhere in the world, but we believe if we all work together as a country we can achieve it.”

The project includes funding from the government, local councils and the private sector. The government is leading things off with an initial $28 million ($19.7 million) investment in a company called Predator Free New Zealand. The support is in addition to the $60 to $80 million already invested in pest control by the government every year.

The new company's goal will be to identify "large, high-value predator control projects" and help draw other investors in to increase their success.

The introduction of invasive predators

stoat in high grass Stoats were brought to New Zealand to handle the overabundance of rabbits. (Photo: CREATISTA/Shutterstock)

New Zealand has very few native mammals. According to the nation's Department of Conservation, the only exceptions are bats and marine mammals, including many species of dolphins, seals and whales.

Rats were first introduced to the island by Maori settlers as a food source more than 700 years ago, reports NPR. They decimated a number of native species, but then were wiped out in turn by rats that arrived accidentally on European ships.

Stoats, ferrets and weasels were brought in to handle plagues of rabbits. Rabbits had also been introduced intentionally for food but reproduced in overwhelming numbers. Stoats caused the extinction of several bird species.

Possums were introduced in hopes of starting a fur trade. Their prey includes snails, beetles and many native birds and they compete directly with many native birds, including the kiwi, for food and resources.

kiwi bird The New Zealand government hopes ridding the nation of predators will help native birds, including the kiwi. (Photo: New Zealand Department of Conservation)

Existing pest control methods in New Zealand include the controversial use of aerial poison drops, trapping and ground baiting, and possum hunting by ground hunters, according to the Guardian.

Emeritus Professor of Conservation Mick Clout from the University of Auckland told the paper he was “excited” by the “ambitious plan” which if achieved would be a “remarkable world first.”

“The biggest challenge will be the rats and mice in urban areas. For this project to work it will need the urban communities to get on board. Possum extermination will be the easiest because they only breed once a year and there are already effective control methods in place.”

One major exception

feral cat in the wild Cats haven't been named in the New Zealand predator plan, but they are fair game if they're in conservation lands. (Photo: Joseph M. Arseneau/Shutterstock)

Interestingly, one killer predator has been left off the list: cats.

In New Zealand, cats have contributed to the extinction of nine native bird species and have an impact on 33 endangered native bird species. Philanthropic economist and businessman Gareth Morgan envisions a New Zealand free of cats and his website, Cats To Go, was set up to promote the campaign.

Morgan doesn't suggest New Zealanders euthanize their cats (although his website does mention it as an option), but he urges pet owners to keep their cats inside and not to replace them when they die.

Keeping them inside is definitely a good idea. In an interview with Radio New Zealand, Key said that feral cats found on conservation lands would be targeted just like other predators.

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.