Community groups in New Zealand's Wellington are aspiring to turn their harbor-side metropolis into the world's first predator-free capital, in the hope of bringing back the kiwi and other unique birds, lizards and insects.

Aptly named Predator Free Wellington, the nonprofit organization has already eradicated almost 30,000 rats, stoats, weasels and possums from the greater Wellington area.

"It's believed these three species eat 25 million native birds a year -- that's about 68,000 birds a night," said James Wilkinson, project director of Predator Free Wellington. "They're literally munching through our native biodiversity."

Wilkinson reached into a large plastic box and produced a pristinely taxidermied stoat and placed it on the table -- eyes wide and teeth bared -- alongside a similar-but-smaller weasel, a rat and a flat, yet-to-be-stuffed possum.

At first glance it's difficult to imagine how these small animals could cause so much damage to New Zealand's ecosystem. But as Wilkinson explained, the country's native wildlife evolved over millions of years with no land-based mammals, other than bats, and as a result, they aren't equipped to fight even the smallest of predators.

(James Wilkinson with staff from the Zealandia eco-sanctuary and a trap used to capture and kill predators)

"In that isolation, New Zealand became a land of lizards and birds, and without needing to escape from anything, our birds got pretty lazy and lost their wings," he said.

The country is home to the largest number of flightless bird species, both living and extinct, and its national animal, the kiwi, is one of Wilkinson's so-called "lazy" birds.

About the size of a chicken, flightless and with terrible eyesight, the kiwi, absent from Wellington for over a century, is vulnerable to attacks from stoats, which were imported in the late 19th century to control rabbit plagues.

Stoats, weasels and ferrets are blamed for about half of all kiwi chick deaths. Cats, dogs, possums, wild pigs and rats also pose a threat to the birds, as do cars.

Rats compete with kiwi for similar food sources and eat bird eggs, as do possums, which also strip the delicate leaves from native trees, affecting the entire forest ecosystem.

"You introduce these guys and native animals really have no chance," Wilkinson said.

Each year, New Zealand spends roughly NZ$70 million (US$45.6 million) in an attempt to control these pests, but their numbers inevitably bounce back.

"If we don't go for this end goal of zero, then we're stuck doing what we've always done," Wilkinson said passionately.

Launched in 2016, Predator Free Wellington supports 32 community groups that work together to eliminate introduced species from the 30,000 hectares of land in Wellington city and the surrounding areas.

While New Zealand has a history of successfully eliminating nonnative carnivores from offshore islands, working in an urban environment presents many more challenges.

"We're doing things like having to monitor our storm water and wastewater networks to see if rats are using that, we're talking to supermarkets about how freight comes in from outside the region, talking to businesses to understand how they deal with their waste, because that provides refuge and food for rats," Wilkinson said.

However, working in a city of roughly half a million people has one significant advantage: more hands on-deck.

Wilkinson said he was surprised by just how positively the greater Wellington community responded to the project, with school groups coming on board and people uploading photos of predator-free-themed cakes to social media.

One of the key ways Predator Free Wellington supports community groups is through providing backyard traps -- wooden, tunnel-like structures with a rat trap in the center -- so residents can eliminate predators in their own gardens.

(A trap, baited with a chicken egg, inside the Zealandia eco-sanctuary in Wellington) 

According to Wilkinson, the backyard trapping movement "went massive" and became a point of community cohesion for thousands of locals.

"We have new refugee families arriving in a community and they're being welcomed with a trap in a box. That's an immediate link into what's happening in their community," the former Conservation Department ranger said.

"Wellingtonians have really stepped up and said, 'This is our city and we want to be part of this'."

Residents' enthusiasm for becoming the world's first predator- free capital was perhaps most keenly felt when a rogue weasel made its way into Zealandia, a fully-fenced, 225-hectare eco-sanctuary, roughly 10 minutes from the central business district, in early October.

Once news of the weasel broke, locals started visiting the park specifically to help find the intruder.

"I think it's a story that people really identified with," said Stephen Moorhouse, lead ranger for education and youth at Zealandia. "I think they took it a little personally that something was trying to take away the animals and critters they have a relationship with here."

Almost two weeks later, the weasel was found dead in one of the 110 traps set specifically to trap the intruder, much to the relief of Zealandia staff and locals.

But Zealandia is more than a picturesque park for New Zealanders to become reacquainted with native flora and fauna. It also plays a key role in Predator Free Wellington's goals to reintroduce native animals back into the city's suburbs.

As bird populations inside Zealandia grow, species like the tieke -- a medium-sized forest bird -- are spilling out into the surrounding urban environment.

"The tieke was down to one last remnant population of about 500 (birds), on an offshore island," explained Wilkinson.

"But now they're spreading out from this place (Zealandia) into the suburbs surrounding Wellington, so our children are seeing birds that you would otherwise have to travel many, many miles offshore to see to connect with."

Although only two years into their 10-year project, success of other predator-eradication programs around the region have the Predator Free Wellington team confident that they will see kiwis roaming the underbrush of the city's suburbs again.

"Native biodiversity responds incredibly quickly, a lot quicker than we give it credit for," Wilkinson said.

"We've decimated our native biodiversity in a very short space of time, so this presents a really unique opportunity to change the tide and hand over an environment to the next generation that isn't half trash for the first time in a long, long time."