WELLINGTON, New Zealand – The volunteer climbed down the cliffs, moving along a series of knots on a thin rope as he made his perilous way about 100 feet down a sheer cliff face to the small box he had to refill with poison.
It’s one of thousands of such boxes, many in equally inaccessible places, that have been distributed across the Miramar Peninsula south of New Zealand’s capital Wellington over the past month.
Conservationists and volunteers, like cliff-hanging Dan Henry, have set traps with fresh rabbit meat, sprinkled poison baited with aromatic bait, and combed footage from cameras across the headland to address the ermine problem in the area.
A problem that seems to consist of a single ermine.
That humans are willing to go to such lengths to track down a single predatory mammal is a testament to the severity of New Zealand’s biodiversity crisis. Its native birds, lizards, and bats evolved in the absence of predators that only arrived in recent centuries.
Many of its most famous native creatures are flightless. As a result, they are defenseless against predators like stoats – weasel-like creatures with jagged teeth and remarkable agility – which were introduced to New Zealand in the 19th century to control rabbits. Approximately 4,000 of the country’s native species are classified as “Vulnerable” or “Endangered” – the highest proportion of threatened native species in the world.
Activists on the Miramar Peninsula have pledged to rid the peninsula — which was teeming with unwanted mammals until the 2010s — of nearly all predators. (Domestic cats, which remain politically untouchable despite their ability to kill, are an exception.) Their goal may seem unrealistically ambitious, but it’s become normal in New Zealand, where the government made a 2016 pledge to eliminate most non-native predators by 2050.
“Many of our species give our country its sense of identity,” said Kiri Allan, New Zealand’s conservation minister. “Our national feeling is endangered.”
After six years, the campaign has achieved remarkable success. New Zealand’s Department of Conservation has placed one thousand square miles of land under permanent predator control, eradicating predators on 117 of its 600 or so islands and creating several fenced-off predator-free reserves across the country.
Now the country’s conservation community is squabbling over whether it can achieve that goal — and at what cost.
In Miramar — which is connected to the rest of Wellington by a large unfenced isthmus and is home to tens of thousands of people — the department has been working with local volunteers to eliminate possums, weasels and brown rats. Stoats are on their way out and black rats are at their lowest level since records began.
Mr. Henry, co-founder of the Predator Free Miramar volunteer group, is not satisfied. “I don’t think the wins are coming fast enough,” he said.
Nicola Toki, managing director of the conservation advocacy group Forest & Bird, agreed. “At the current speed and scale, there’s a risk we won’t make it.”
However, some in the conservation community question whether getting there is even feasible given how resource-intensive elimination of predators has proven to be.
At Miramar, for example, 5,878 traps and 6,607 poison stations were placed over the peninsula’s three square miles. Each must be inspected regularly, which requires dozens of paid staff and volunteers on site.
Another approach would be to focus on creating more sites like Zealandia, also near Wellington, a fenced-in reserve of nearly a square mile where native wildlife can thrive. New Zealand has a network of such predator-free sites, some on offshore islands.
The protected areas are expensive to build and maintain and can only protect relatively small areas. But while New Zealand’s Predator Free campaign aims to eliminate predators for the long term, fenced reserves provide immediate security.
Conservation advocates want the government to pursue both. But with limited conservation spending, prioritizing one could prevent full adoption of the other.
Ms Allan described the predator-free goal as “ambitious”. In a written statement, she said the government had made significant progress but would focus on “innovation and learning” going forward, with the aim of discovering “more effective and efficient ways to protect our biodiversity on a much larger scale”.
In contrast, Ms Toki insists that total elimination is achievable but requires much more funding and focus from the government. Referring to the roughly $250 million that New Zealand has spent hosting the America’s Cup sailing competition in 2021, she said, “Make the America’s Cup for Predator Free.”
Local activists agree. “Predator Free 2050 is absolutely doable if we choose to do it,” said Mr. Henry. “I think I thought when we started that we were going to start with old tools and a silver bullet would show up and we’d all breathe a sigh of relief.” But that didn’t happen, he said. “It just takes boot leather, traps and poison and we can place that anywhere we can.”
As he leaned over a trap with a stick to demonstrate what happens when the mechanism is triggered, he suddenly heard a flapping and beeping sound at his shoulder. A pīwakawaka—whose tail feathers resemble an extended accordion—perched on a nearby branch. The number of native birds on the peninsula has skyrocketed since the start of the predator-free campaign.
Mr. Henry recognizes that total elimination is not the only measure of victory. Nonetheless, he and other members of Predator Free Miramar are determined to achieve their goal of showing that it can be done on a national scale.
“People see the success we’ve had here,” said Mr. Henry. “You want to do it again. We are a true demonstration of what can be achieved if you work at it and the community lags behind.”
This also includes tracking down the last ermine. Sue Hope, a local volunteer, is optimistic she’s already been poisoned or trapped. Still, she spends every Sunday morning trudging over hills resetting traps and filling up poison stations just to be safe.
“Ermines are terrible,” she said. “They kill things for no reason, not even to eat them.” She then dives off the track and burrows under a thorn bush in search of the next trap to check.