On Mainland New Zealand, Crafty Kākāpō Are Thwarting Reintroduction Efforts

Ten of the critically endangered parrots were released into a sanctuary in 2023 with hopes of eventually establishing a wild population. The only problem? The birds keep escaping.
A bright green kakapo emerges from a bag on the ground held open by a person's hands.
Kākāpō Motupohue released at Sanctuary Mountain Maungatautari in July. Photo: Peter Drury

In the wee hours of the morning on January 2, 2024, a driver spotted a bird sitting in the middle of a rural road in New Zealand. Fortunately, the startled driver realized that the fluffy green mound was a Kākāpō, a critically endangered parrot endemic to the country, and he quickly called the Department of Conservation’s hotline to report the sighting. Within a few hours, rangers safely returned Elwin the Kākāpō to Sanctuary Mountain Maungatautari (SMM)—the bird’s home since September 2023.

Elwin, a 15-year-old male, was one of two cohorts of 10 male Kākāpō translocated from Whenua Hou (Codfish Island), a southern offshore island, to SMM on New Zealand’s North Island in July and September 2023 as a part of the species’ long-term recovery plan. The reintroductions mark a huge achievement for the effort: the first time the largely flightless birds have lived in mainland New Zealand in nearly four decades, and the first time Kākāpō have lived wild there in more than 100 years.

“To know that we’ve got Kākāpō out on the mountain is pretty special and also feels like quite a responsibility,” says Janelle Ward, the biodiversity team leader at SMM. “We really want them to be healthy and settle in well and to be safe here.” But since being released, 6 of the 10 birds have earned return flights to Whenua Hou after venturing beyond the 8,310-acre sanctuary’s enclosure or showing signs of possible escape. Four Kākāpō—Ōtepoti, Bunker, Taeatanga, and Tautahi—remain at the sanctuary, where undeterred researchers still hope dozens or even hundreds will one day roam. 

Kākāpō, a culturally important species for the iwi, or Māori tribes, of Aotearoa (New Zealand), once thrived in dense forests across the country’s three main islands, where males set up leks on peaks and boomed loudly to attract females. The arrival of humans and the introduction of non-native species, like stoats, rats, and feral cats, decimated their population. Nearly extinct since the 1990s, when just 51 individuals remained, Kākāpō are now a global conservation success story.

Until recently, however, the entire population of 247 individuals lived on southern offshore islands, protected from the onslaught of invasive predators elsewhere in New Zealand. But the population has exploded in the past decade—doubling since 2016 alone—forcing the team to look for other safe havens for Kākāpō. “We didn’t expect it to grow that fast, and suddenly we’ve got this situation where our main breeding islands are full,” says Andrew Digby, the lead biologist with the Kākāpō Recovery group, who’s worked with the endangered species for the past 10 years.

The predator-proof fence around Sanctuary Mountain Maungatautari was modified with strips of smooth sheet metal to (hopefully) keep the Kākāpō from climbing out. Photo: Janelle Ward

The Kākāpō Recovery group flagged SMM as one of the only suitable places on the mainland—basically an oasis of native vegetation surrounded by farmland, Digby says. SMM hosts 22 endangered New Zealand bird species, and a 6-foot-tall fence surrounds the sanctuary’s nearly 30-mile circumference. But the predator-proof barrier wasn’t built to contain Kākāpō—though flightless, they climb readily, using their beaks and talons to scale trees and fences. Outside the enclosure, the birds could easily fall prey to an invasive predator, so the Kākāpō Recovery group tested various fence modifications before the reintroduction to prevent the birds from climbing out. It took nearly 30 volunteers and sanctuary staff about 9 months to install thousands of smooth metal sheets to keep Kākāpō from scaling the fence. 

“Perhaps we underestimated, for a lack of a better word, the athleticism of these birds.”

Yet, somehow, they’ve managed to escape. “It’s high stakes when a bird is outside the sanctuary—it’s an anxious time,” says Dan Howie, one of the rangers tasked with monitoring Kākāpō daily. “Perhaps we underestimated, for a lack of a better word, the athleticism of these birds.”

Several of the parrots escaped in quick succession in October 2023, so the team kicked monitoring into high gear. The researchers try to stay as hands-off as possible, instead relying on tracking technology. NoraNet—essentially a Fitbit for Kākāpō—detects birds if they pass within a certain distance of receivers. But it works best when birds are higher on the mountain, missing individuals when they descend into valleys. Each bird also wears a radio transmitter and GPS attached like a miniature backpack. Rangers ride ATVs or hike across the rugged terrain, carrying a large antenna that helps them triangulate each Kākāpō's location to within 300 feet a few times per week—the more, the better. While the GPS doesn’t currently allow for live tracking, data downloaded after the birds are recaptured, such as during their health checks, can reveal fine-scale movements and even potential escape routes.

Despite these tools, the curious Kākāpō continued to thwart reintroduction efforts. In November 2023, the Kākāpō Recovery group made the difficult decision to relocate 3 of the escape artists birds back to the southern islands. And another three birds earned return flights in January 2024 after summiting the fence or suspiciously patrolling the perimeter. “It is a stressful thing for the team,” Ward says of escaped birds. “Is it going to be alive? Is it going to be well?” Besides Elwin’s eventful escape, four-year-old Tautahi walked a mile beyond the barrier before rangers found him. Manaaki, meanwhile, preferred to plop in a patch of blackberry bushes and gorge himself on the invasive plant’s tasty fruit.

Why and how the birds are escaping is unclear. The team suspects the birds climb nearby vegetation that leans close to the fence and use their outstretched wings to “parachute” softly to the ground. “Occasionally they might have an opportunity to get up over the fence, and they aren’t necessarily trying to escape, they’re just trying to get to a different place,” Digby says.

Though just four birds remain at SMM, everyone involved is committed to this trial to ensure Kākāpō’s long-term survival. After the the first bird broke out in 2023, a crew started clearing trees and low-hanging branches near the fence. But vegetation grows quickly, and almost 30 miles of fence mean the staff would have to work nonstop to keep vegetation at bay. Drones, which arrived in fall 2023, can help identify where to prioritize trimming and detect a missing bird faster. Soon, the team plans to set up mini-enclosures within the sanctuary to observe how Kākāpō interact with the fences. They also plan on updating NoraNet later this year to provide more coverage and will begin collecting GPS data more frequently.

Digby and the rest of the Kākāpō crew are still hopeful that the four remaining males at SMM will settle and eventually establish small territories. Though it could take years before the males start booming to attract females, the researchers are patient; releasing the birds to a safe spot on the mainland has been a goal since 2008. And if these four pioneers can stay put, down the road, the  Kākāpō Recovery group could release females to SMM with the ultimate goal of starting a breeding population.

To save the Kākāpō, the team knows they must be flexible and, sometimes, take chances. “You kind of have to take risks when you’ve got an endangered species like this,” Digby says. “You want to be conservative, you want to preserve what you’ve got, but you also need to take some jumps to change things and improve things for the future.”