New Zealand's rarest birds have seemingly come back from the dead.
For decades, they were thought to be extinct until tiny populations were rediscovered, the holdouts that survived against the odds. There's the kākāpō, a mossy-green parrot weighing up to eight pounds, making it the heaviest in the world. Then there's the takahē, a large grassland bird with a red beak and blue ombre of feathers.
Now, New Zealand is undertaking one of the most ambitious conservation projects in the world to save them. It will only work if the country can develop the technology to do it.
Both birds cannot fly, which wasn't a problem for millions of years. New Zealand (also known by its Māori name, Aotearoa) had no land mammals aside from bats, so the birds' only predators were raptors that hunt from the sky.
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That changed when human settlers arrived, first Māori around 700 years ago and then Europeans in the 1800s. They brought mammals with them, predators that had no trouble sniffing out and devouring the ground-dwelling birds. Ever since, most of the country's native birds have been in a downward spiral, with more than 80 percent of birds that breed there at risk.
To give native birds a chance, New Zealand plans to eliminate invasive predators by 2050, including three species of rats as well as ferrets, weasels and their relatives, stoats. In all, it will mean exterminating millions of animals, the largest invasive species removal project in the world, according to conservation experts.
Much of the work is being done with traps, a labor-intensive process that is costly to scale up over vast areas. Overall, eliminating predators is estimated to cost over $100 million per year. So New Zealand is looking to new technology, like automated traps that use artificial intelligence. Genetic research is also underway, potentially to develop ways to stop invasive predators from breeding. Still, even with new tools, some conservation experts say a full eradication still may not be possible.
"Even if we realize it's unrealistic, we'll still be in a position where we've created a whole lot of new tools and technology that's going to allow us to better protect our native wildlife," says Brent Beaven, manager of the Predator Free 2050 program at New Zealand's Department of Conservation. "We should have thriving native wildlife in areas like we've never had before, so there is no loss to this."
Raising one chick at a time
In a windswept grassland on New Zealand's South Island, Glen Greaves is gingerly holding a takahē egg. He's a ranger with the New Zealand Department of Conservation's Takahē Recovery Program and he's checking on a takahē nest.
He holds a flashlight, illuminating the interior of the egg. He's looking for movement from the embryo, a sign the egg will successfully produce a chick, but doesn't see any.
"That's bad news," he says. "The lower the genetic diversity of species, the higher the infertility generally, and we're starting from a very small population of takahē."
Takahē were assumed to be extinct, but in 1948, a small group was discovered in a remote valley. The birds Greaves works with live at the Burwood Takahē Centre, a breeding program that has slowly built up the population since the 1980s. At first, the young chicks were hand-reared, fed every 20 minutes by human caretakers wearing takahē puppets on their arms to mimic real bird parents. Now, takahē pairs are raising their own chicks.
Takahē started to decline after human settlers arrived. The rooster-sized birds were hunted and had to contend with competition for the grasses they eat after deer were introduced to New Zealand. But the biggest hit came from stoats, which were introduced by European settlers to control rabbits – another introduced animal that went awry.
Stoats are only about a foot long, smaller than a takahē, but the pint-sized predators are known to be fearless, taking down both chicks and adult birds.
"They are incredibly smart and incredibly desperate," Greaves says. "So they'll ambush a big takahē, usually on its nest, just jump on the back of the bird and hang on for dear life until it's dead."
After decades of breeding efforts, the population is more than 500 today. Now, the problem is finding safe places for them to live. Some have been released into the wild, but stoats can take a toll.
"There's lots of good habitat, but very few places where we can control predators to the level, to the critical threshold that allows takahē to survive," Greaves says.
Jurassic Park for birds
One place takahē can go is an ecosanctuary – the equivalent of a high-security facility for wildlife, complete with a Jurassic Park-style fence.
At the Orokonui Ecosanctuary outside Dunedin, the fence is designed to keep things out, instead of keeping things in. It's made of a reinforced stainless steel mesh to exclude rats. It extends underground to keep stoats and weasels from tunneling in. The top has a curved metal rim to prevent climbers from getting a toe-hold and an electric wire on top triggers an alarm with 24/7 monitoring.
Inside, the forest is filled with the sounds of birds that are able to thrive without introduced predators.
"It's hard to talk if you're here first thing in the morning – the dawn chorus is immense," says Madison Kelly, who works at Orokonui.
The ecosanctuary is home to a pair of takahē, as well as rare forest parrots and more common birds like the tūī, whose call sounds like a techno dance party. Kelly says the place is especially meaningful for her because of her indigenous Māori heritage.
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"Orokonui is obviously a biodiversity project, but it's also a community project – a place where some of our stories, our forests, our species, our taoka – our treasures, can be active here," she says.
Keeping the wildlife safe takes constant vigilance, however. After a winter snowstorm one year, stoats found a way over the fence. It was when a rare bird, the South Island saddleback, was living in the sanctuary.
"They basically were picked off one by one by those stoats," Kelly says. "It took months and months and months to actually track down those stoats."
With miles of fenceline and maintenance, ecosanctuaries can be costly. So outside the fence walls, there's another strategy underway.
Deploying smarter traps
On a steep hillside, dense with trees, Jonah Kitto-Verhoef is leading Scout, a small dog with a big job. Scout is trained to find brushtail possum droppings. The Australian marsupial was introduced to New Zealand for its fur, but has spread far and wide, devouring native tree foliage and reducing the habitat and food supply for native birds.
There are special traps for possums scattered throughout the area, set up by the Halo Project, where Kitto-Verhoef is the predator-free project manager. Traditional traps can be labor-intensive, requiring regular checking and resetting after an animal is caught. Over a large area, that can require huge amounts of staff time.
The newer traps are automated, resetting themselves after going off. They've been evaluated under New Zealand's animal welfare standards to ensure they're as humane as possible. The bait is also automatically released over time. Mayonnaise seems to work the best.
"Some people swear by Best Foods," Kitto-Verhoef says. "It's like anything – people have their favorite ones."
Some of the traps also have a newer feature: artificial intelligence. A camera inside the trap identifies the animal and only triggers the trap if it's a targeted species. Kitto-Verhouf says that makes the traps safer and provides useful data, since they remotely track what's being caught and whether some possums are harder to catch.
"Machine learning and artificial intelligence can really help improve our work, save us a lot of time and money and actually make it so much more effective," he says.
The project has culled thousands of invasive animals so far. Kitto-Verhoef says if those animals weren't dying, it would be thousands of native birds instead.
"Do the animals that have been here for millions of years, evolving in isolation, have an intrinsic right to life?" he says. "I personally believe they do."
Public polling shows New Zealanders are largely supportive of getting rid of invasive animals, though some disagree on the methods for achieving that goal. The SPCA in New Zealand, an animal rights group, supports finding non-lethal methods of control, though it recognizes the need to manage the non-native species.
Searching for genetic targets
New Zealand researchers are also developing more targeted ways of eradicating invasive species – using genomic research. At the University of Otago, associate professor Tim Hore and colleagues have sequenced the genome of the brushtail possum.
"It is definitely a new era," he says walking through his lab. "There is a huge amount to learn and lots of great possibilities."
Having the genetic sequence is only the first step, since researchers still need to map out what specific genes do. But that opens the door to finding toxins that only work on one species of animal, while sparing others. In the 1960s, a rat poison was developed that's only lethal to rats, though its use didn't become widespread.
Conservationists are also discussing the use of genetic modification to control animal populations, using what's known as a gene drive. It's a way to make a genetic change stick across generations.
Here's how it could work: animals are released into the wild with modified genes that ensure all their offspring are males. That next generation, entirely male, also has the same modified genes, so their offspring would be male. Over time, the population becomes entirely male.
"Therefore, breeding slowly grinds to a halt," Hore says. "It's about making sure that all individuals possess the gene change that you want."
Releasing genetically modified animals could have unforeseen consequences, though. While brushtail possums may be a nuisance in New Zealand, they're a protected species in Australia. If modified animals escape or are accidentally moved, they could crash populations in places they're not intended to. Conservation researchers say a safety measure could involve gene drives that disappear after a certain number of generations, but the risks need to be heavily weighed.
"It's an interesting space that needs a very long social discussion within New Zealand around its use and the potential impacts," says Beaven of New Zealand's Department of Conservation.
As invasive species spread around the planet, the technology and techniques being developed in New Zealand have the potential to help endangered species in other countries. Beaven says those tools will be crucial to making New Zealand's goal both feasible and affordable.
"We're seeing a rate of change of technology and thinking that is completely step-changing the way we approach conservation in New Zealand," Beaven says. "We want to keep refining and developing new technology to drive that cost down, because trying to achieve eradication over 26 million hectares is going to be quite a pricey exercise."
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