This week the Government committed itself to what's been dubbed the world's most ambitious conservation project - eradicating rats, possums and stoats by the year 2050.
But what happens when a species that was introduced to the eco-system in the first place, is then removed?
"Just as adding new species changes the ecosystem, removing species also creates predictable and unpredictable changes," says ecologist James Russell.
So removing rats, for example, could boost the population of mice, because they'll have more space to breed and will no longer be competing for the same food.
However that doesn't mean we're heading for a mouse plague.
The role of ecologists is to decide whether these changes could make the pest problem worse, and it's likely most will agree that it'd be better to have only mice than rats and mice.
But is it actually possible for the country to be predator free by 2050? Conservation Minister Maggie Barry thinks so, and says she's the woman for the job.
"I'm known as the party's biggest killer. Twenty-five million rats last year!" she says.
Twenty-five million and counting - 'Biggest Killer Barry' is confident the rat race can be wiped out within 34 years
She's likened the mission to landing on the moon.
"As in the words of John F Kennedy talking of the Apollo project, 'We choose to do these things not because they are easy but because they are hard'," Ms Barry says.
That's one small step for the Government, one giant leap for our native species.
Newshub.
