Mila McKenzie inspects an animal trap in a park in Dunedin, New Zealand. Her student-led group plants trees and traps invasive animals that are killing native birds.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
Like many student volunteers, the kids in the group Town Belt Kaitiaki look after their neighborhood parks — planting trees, weeding, clearing paths. But they also do something less common: exterminating animals.
“So we have a possum trap — the white ones that are up on the trees,” says Finn Hibbert, age 18, pointing to a white and metal box designed to kill brushtail possums, an Australian marsupial. Other traps scattered throughout the park also kill rats.
Rats and brushtail possums spread across New Zealand after being introduced by human settlers. Rats (left) eat bird eggs and chicks, while possums (right) eat tree foliage, reducing habitat and food supply for native birds.
David Mudge/Ngà Manu Images; Department of Conservation New Zealand
hide caption
toggle caption
David Mudge/Ngà Manu Images; Department of Conservation New Zealand
“The whole reason we trap these sorts of creatures is they can be damaging to native birds and other native animals that you want here,” says Mila McKenzie, age 13, who also volunteers with Town Belt Kaitiaki.
The group’s trapping project is part of a nationwide effort, one of the most ambitious conservation projects in the world. New Zealand is trying to eradicate many of its invasive species — animals that were brought to the country by humans and have wreaked havoc on the native wildlife ever since. (New Zealand is also known by its Māori name, Aotearoa).
New Zealand has rare birds that are found nowhere else, like the fuzzy and flightless kiwi. Invasive predators have helped drive 62 native bird species to extinction, and more than 80% of the remaining ones that breed in the country are at risk.
To save those birds, New Zealand set a goal of eliminating invasive predators by 2050, likely tens of millions of animals, if not more. While the government is leading eradication efforts, local volunteers are getting involved across the country, even setting up traps in their own backyards.
Conservation experts say to reach that goal — the equivalent of an environmental moonshot — community participation will be crucial. Invasive animals would need to be removed from both private and public land, and the public would have to remain vigilant to prevent animals from reinvading.
“Predator-free New Zealand is as much a social challenge as it is a biological challenge,” says Emily Parke, who studies the ethics of conservation at the University of Auckland. “This isn’t just about coming up with the right technologies and methods. It’s about a lot of social change.”
Mila McKenzie checks a chew card, a piece of cardboard scented with bait. It attracts animals like possums and rodents, which nibble the edges of the card, alerting the group when invasive predators are in the area.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
Bringing birds back to the community
In a neighborhood park in Dunedin, New Zealand, Hibbert and Mila spot a kererū, a pigeon the size of a chicken. The songs of other native birds can be heard echoing in the trees, a hopeful sign for the group.
“You see that our efforts are starting to make a difference, even if it’s only one possum at a time,” Hibbert says.
A stand of native trees, recently planted by the students, is starting to grow in. Brushtail possums devour tree foliage, reducing the food supply and habitat for native birds, so restoring the forest is a key step in bringing birds back. Nearby, the group tracks wildlife that walks through using a “tracking tunnel,” which has an inked strip of paper inside that animals walk across and imprint their footsteps on. Rats, which prey on native bird eggs and chicks in their nests, are common.
Finn Hibbert of Town Belt Kaitiaki says conservation is becoming part of his generation. “The more birds we start to see, we get to see the result of our tree planting and our work and our trapping.”
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
For millions of years, New Zealand had no land mammals aside from bats. Without predators on the ground, some birds evolved to be flightless, relying on camouflage to evade eagles and other raptors that hunt from the air.
Mammals arrived with human settlement, first Māori around 700 years ago and then Europeans in the 1800s. Rats hitched a ride on ships, while other animals were brought intentionally, like brushtail possums for the fur trade. The stoat, a relative of ferrets, was brought to control rabbits, another introduced species whose population boomed. It quickly became a voracious predator for native birds.
Tracking cards capture animal footprints with ink, allowing the group to identify which invasive species are present in the park.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
With native wildlife in a downward spiral, New Zealand has embarked on what conservation experts say is the largest invasive species removal project in the world, both in terms of area and complexity. Many experts say that goal is likely out of reach without new technology to more efficiently capture animals. But the effort has already led to the development of new traps, which are safer for humans to use and meet the country’s animal welfare standards.
Takahē are another of New Zealand’s flightless birds. They were thought to be driven to extinction by humans and invasive predators, but now are being brought back through captive breeding.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
Town Belt Kaitiaki uses some of those newer traps. The group does safety training for its members and is supported by staff at City Sanctuary, a community predator-free group run through the city government. The kids say trapping is part of a difficult trade-off in New Zealand — if they weren’t getting rid of invasive animals, native birds would be dying instead.
“Though it is a bit gross sometimes, it’s actually quite an ethical thing because it’s easy if you kill off something that’s causing a problem, instead of letting them kill off everything else,” Mila says.
A coalition of community groups traps invasive predators across Dunedin, New Zealand. On one peninsula, the coalition believes there are only a few possums left after more than 20,000 were removed.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
Conservation in your backyard
Around New Zealand, communities are also creating networks of backyard trappers. In Whakatāne, James McCarthy spots a black and blue bird in his yard on a rainy morning. It’s a tūī, a native bird with a call that sounds like a techno song.
“What we noticed here was that the birds started coming back,” he says. “We’ve seen heaps of birds returning and nesting.”
McCarthy says he was drawn to the trapping effort after putting in a garden with native plants. McCarthy keeps four traps in his backyard, as well as a few in the neighborhood. Some of his traps automatically reset themselves, but he and his wife check them daily. So far, they’ve killed more than 100 possums and rats.
James McCarthy sets up a trap in his backyard in Whakatāne, New Zealand. He’s one of about 600 trappers across town who volunteer to combat invasive species to help protect New Zealand’s native birds.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
“It’s a cumulative contribution that individuals can make,” McCarthy says. “I don’t feel vengeful about it, but definitely it’s our responsibility. Especially as a colonized country, all the things that were introduced into it were brought here by colonizers.”
One example: hedgehogs, which McCarthy has also trapped. They were introduced to New Zealand to remind Europeans of home by “acclimatization societies,” colonial groups dedicated to bringing animals from overseas. Today, it’s estimated that there are more hedgehogs in New Zealand than in the United Kingdom, where they’re from. McCarthy traps them because they prey on native bird eggs and insects.
“Some people really don’t like the fact that I do that, but they’re just in the wrong place,” McCarthy says. “They’re a devouring machine for our species.”
Cats are another polarizing species in New Zealand. Feral cats also take a heavy toll on native birds, but are currently not one of the species in the country’s Predator Free 2050 goal. Some conservationists are now calling for them to be added to the eradication program. New Zealand’s SPCA, an animal rights group, doesn’t oppose the killing of feral cats, though it opposes methods that could cause the animals suffering. The group recognizes the need to control invasive species, but prefers nonlethal methods of control.
Whakatāne is just one of many New Zealand communities that have formed predator-free groups. “It feels like the whole country is onboard,” says Keturah Bouchard, who volunteers in Whakatāne.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
A big goal needs social buy-in
New Zealand’s birds are part of the national identity, even printed on the country’s money. New Zealanders are nicknamed “kiwis.” Awareness about endangered species is high, and surveys show that much of the public has participated in conservation work.
“The public response and the public support for predator-free as a program of work has far exceeded anything I imagined would ever be possible,” says Brent Beaven, manager of the Predator Free 2050 program at New Zealand’s Department of Conservation.
Jame McCarthy walks down a neighborhood path where a line of traps is set for invasive species. “We see the results remarkably quickly when they’re removed from the environment,” he says.
Ryan Kellman/NPR
hide caption
toggle caption
Ryan Kellman/NPR
Still, eradicating predators could mean using new technologies that have less public support. Scientists are studying how to genetically modify invasive species to interrupt their reproduction, something Beaven says would only be deployed after a lengthy public discussion about the risks.
Even with public participation, the goal of eliminating invasive predators completely may not be possible. But conservation experts say even simply suppressing their numbers gives native wildlife a better chance.
“It might not be in my lifetime, but these kids that we’re engaging with now hopefully will get so engaged with their environment, they’ll come up with the solution,” says Bridget Palmer, lead project manager for Halo Whakatāne, a group that supports community predator-free work. “It’s ensuring the next generation builds on the vision that this generation has.”
