We make our way down a steep wooded slope, holding onto trees and bracing our feet sideways against roots. We’re off trail, but Paul Ward, an app designer and self-described “lifelong bird nerd,” knows the way.

All at once we come upon a young man, blonde and bearded, sitting alone on the ground. He’s gazing meditatively at a homemade parrot box.

The man has the hipster air of a musician or student, and he may well be both, but right now he’s a volunteer—for the Polhill Protectors, a Wellington citizens’ group working to make this urban park, called the Polhill Reserve, into a safe haven for rare native birds. Every few weeks he sits for an hour at this box to keep track of whether kaka parrots are nesting in it.

North Island kaka are large parrots with scarlet, rust, and brown plumage and amazing calls and songs. When Ward, a co-leader of the Protectors, was a boy, there were no kaka anywhere near Wellington. Habitat destruction and introduced animals, especially stoats, had driven them locally extinct.

New Zealand's Most Famous Bird In the dead of night, the extremely rare, brown kiwi leaves his burrow for the pitch dark of the primeval New Zealand forest.

Today there are hundreds of kaka in Wellington. They gather raucously in back gardens and drill into trees for insects. Some Wellingtonians have even taken to calling them pests, noting that they damage historic trees and pull nails out of roofs.

But to the Protectors and like-minded Kiwis, the return of the kaka and other native birds to Wellington is an ecological triumph—one that began in 2002, when the first of 14 kaka from zoos were released in the middle of the city, in an unusual wildlife sanctuary now known as Zealandia.

An Island in the City

New Zealand split off from supercontinent Gondwana 85 million years ago, before mammals colonized the world, and so for most of its existence it had none; it was an Eden dominated by birds when humans first arrived around 800 years ago. Since then—and especially since Europeans arrived in 1769—predatory mammals like cats, rats, stoats, and Australian possums have moved in, brought intentionally and unintentionally by humans. Without evolved defenses against these canny predators, New Zealand's unique bird life was hit hard. Many species now survive only on remote islands off the main ones.

Zealandia covers 550 acres in Wellington. Birds breeding in safety inside its protective fence have spread to other parts of the city. Photograph by Hemis, Alamy

Zealandia, which describes itself as “the world’s first fully-fenced urban ecosanctuary,” is an island in the city. The fence is no joke. Over five miles long, encircling 550 acres, the $1.2 million fence is over six feet tall, with an overhanging top and a tight metal mesh that keeps out rats, cats, stoats, possums, and other non-native critters. A few smaller enclosures inside the sanctuary have fences tight enough to exclude mice, which are notorious for their ability to squeeze through the tiniest of spaces.

Zealandia is “a reversal of the idea of the city as a biodiversity wasteland,” says Danielle Shanahan, Manager of Conservation & Research at the sanctuary. In the late 1990s, members of the Royal Forest & Bird Society convinced the Wellington City Council to convert city property once occupied by a water reservoir into a predator-free nature reserve. By siting it inside the city, the project aimed to introduce urban New Zealanders to their rare and endangered biodiversity, especially the country’s fantastic birds.

More than 100,000 people visit Zealandia each year, looking and listening for one of the country’s five species of kiwi, the little spotted kiwi; for the sturdy takahe, also flightless; for the green, melodious tui; and for dozens more.

When I visited, I was particularly charmed by the toutouwai, or North Island Robin, which isn’t closely related to European or American robins but is similarly fearless. After Shanahan scuffed a bit of dirt off the path, one of theses adorable fluff-balls immediately emerged from nowhere to check the spot for tasty invertebrates. The tiny colored bands that zoologists use to track the birds rattled around its long legs.

But Zealandia is much more than merely a zoo, and perhaps its most exciting characteristic is the so-called “halo effect” it has on nearby areas—including Polhill Reserve. For although Zealandia is secured with a serious fence, the fence doesn’t have a lid. And even in kiwi country, many birds can fly.

Some MAMLs Are Helpful

It was before the parrots had become numerous enough to be troublesome, around 2006, that Ward, recently returned to New Zealand after a decade living abroad, spotted one on a jog around Wellington. He knew they were curious, so he held out a bit of shiny metal—a key or coin, he can’t remember which. The parrot approached to investigate, eventually alighting on his arm. “I’d never seen one anywhere other than an offshore island,” he says. “I was just gobsmacked.”

Seized with enthusiasm, Ward wondered what he could do to “be neighborly” to these native birds spilling over the fence from Zealandia. He joined Polhill Protectors when it was founded in 2013, committing to trap predators in the scruffy nature reserve, which lies just outside the fence. In 2015, he became co-leader of the group.

Polhill is 175 acres of wooded gullies, popular with what Ward describes as MAMLs—middle aged men in lycra. As we hiked its trails, we had to step aside frequently as highly fit fifty-year-olds barreled past us on mountain bikes. Many of those bikers and runners now carry wrenches they use to check traps tucked in the bushes just off trail for rats or hedgehogs. Each wooden trap is baited with peanut butter or Nutella and stenciled with the group’s symbol, a Maori birdman. Ward says he is inspired by the Maori concept of kaitiakitanga, which means something like guardianship over an area, species, or thing.

The woods are hardly untrammeled nature; they’re a mix of native and introduced plants, whatever grew back after farming ended in the area. “Whatever it once was is gone,” Ward says. “It is a completely new ecosystem.”

Kaka parrots, once nearly extinct, have become so numerous in Wellington that some people consider them pests. Photograph by David Wall, Alamy

Nevertheless, it is an ecosystem the Zealandia overflow birds can thrive in, as long as the Protectors keep on top of trapping to keep the density of predators down. Many bird species now nest in the reserve, including kaka, toutouwai and an elegant songbird with a red saddle called a tieke. Tieke were completely extinct on mainland New Zealand until they were reintroduced to Zealandia. As Ward and I wander Polhill, we hear one of their calls, and his face falls into an expression of profound rapture.

“To see these birds back in a lived environment is really cool,” he says. “Polhill has a better dawn chorus than most national parks.”

At the end of our walk, we emerge from the woods into a sports field and playground. A brand new soccer backstop painted by local artist Phoebe Morris illustrates some of the introduced predators that the Polhill Protectors are trapping, so children can at least symbolically help by kicking their soccer balls against them. For an outsider, the focus on killing feels strange, intense, and even ungreen. But in New Zealand, introduced predators are ecological enemy number one—unlike elsewhere, where habitat loss is usually the biggest factor in bird declines.

Zealandia, Polhill, and similar efforts have inspired New Zealand’s political leadership to announce a lofty goal: Ridding their entire country of rats, stoats, and possums by 2050. The “Predator Free 2050” campaign is extremely ambitious, according to most ecologists, but it seems to have captured the kiwi imagination. Families across the country have taken up trapping as a civic and environmentally minded hobby.

Shanahan is a big fan of the campaign, but she is less sold on the name and the focus on killing predators rather than on the native species at risk. After all, trapping and killing aren’t the goal, they just are one tool that the country could use to achieve a goal of rich, diverse, thriving communities of native birds and other species. “The outcome isn’t predator free; the outcome is nature rich,” she says. Nature Rich 2050 anyone?