To Save Its Birds, New Zealand Plans To Kill All Its Rodents


Katy Evans

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

Managing Editor


The seriously cute and basically helpless flightless kiwi. Urban Napflin/Shutterstock

New Zealand is famous for its endemic species. From its national icon, the flightless kiwi, to the colorful kakapo, it has hundreds of creatures that are not found anywhere else in the world. Sadly, this makes them incredibly vulnerable to introduced species, and New Zealand has hundreds of those too.

But the New Zealand government has a radical plan to help give its birds a sporting chance at recovery: kill all its rodents. And it means all of them.


The government announced its plan back in July last year. In a “world first” project, it aimed to make the nation predator free by 2050, wiping out rats, possums, and stoats. Managing these three predators for conservation and agriculture cost NZ$70 million a year, it said.

On top of that, it’s estimated that 25 million native birds are killed a year, including about 20 kiwis a week, which now number less than 70,000. The estimated number of possums in the country is 30 million. There’s no way of guessing rat numbers.

When New Zealand split away from the supercontinent Gowandaland 85 million years ago, a lack of predatory mammals meant many species of birds evolved to not need flight, strolling around on the ground instead.

With the arrival of people came the arrival of small, predatory mammals. Rats stowed away on ships, possums were introduced for fur trapping, and stoats were brought over to try and control the rabbit population. Since then, more than 40 bird species have disappeared completely.


So the need to control the pests is understandable, but how you eradicate three different species from an area the size of New Zealand is a little mind-boggling. When it was signed into official government policy nine months ago by then-prime minister John Key, he described the plan in almost military tactical terms.

Starting with islands and peninsulas the plan is to choke the animals off there, and then advance on to the mainland. Around 150 islands have already successfully become pest-free, with the aim for all of them to be by 2025, as well as 20,000 hectares (nearly 50,000 acres) of the North and South Islands.

How to do it involves hunting, self-resetting traps, predator-specific toxins, ground baiting, and drones, but hopefully less of the controversial 1080 aerial drop poison, a biodegradable pesticide that is incredibly effective at mass killing, sometimes to the detriment of its unintentional targets.

The government has committed NZ$28 million over the next four years and NZ$7 million a year thereafter, though the project is expected to cost billions. However, it has its detractors, with some saying the government isn't spending enough and the scheme is too ambitious. Others think it is ignoring other considerable pests such as feral cats and is distracting from other improvements in biodiversity.

  • tag
  • biodiversity,

  • birds,

  • New Zealand,

  • pests,

  • endemic