Once, under the towering rimu and tōtara of Rakiura (Stewart Island), the booming calls of kākāpō resonated through the night. These moss-green, flightless parrots thrived here, along with kiwi, Harlequin gecko, southern dotterel, kākā, and penguins. Introduced predators drove kākāpō to offshore islands. Remaining species, and the forest teeter on the brink of survival.
Predator Free Rakiura could change everything.
Set to kick off in autumn 2025, the project isn’t just a lifeline for wildlife – it’s New Zealand once again aiming to achieve what no other country has.
Renowned for pioneering predator eradication on islands, this is the most daring challenge yet to remove rats, possums, feral cats and hedgehogs across the inhabited island. Predator Free Rakiura will reaffirm New Zealand as a world leader in nature restoration on a scale never before attempted.
Kākāpō dreaming
Ridding Rakiura of predators will mean kākāpō, once abundant on the island, can return.
And the timing couldn’t be more critical – kākāpō are running out of space. In 2023, ten kākāpō were translocated from their Whenua Hou (Codfish Island) stronghold to mainland fenced sanctuary, Maungataurari Sanctuary Mountain. However, the experiment revealed the challenges of fenced containment – six birds have already been sent back to Whenua Hou after making daring escapes beyond the fence.
The Department of Conservation has its eyes set on Rakiura, but it must be predator free first.
With a permanent population of 400 people, Rakiura is a hilly, bushy island roughly the size of Singapore. The island has some unique advantages in its fight against predators.
Incredibly, it’s already free of stoats, ferrets, goats, pigs and mice, and there’s a good network of traps in the township. Plus, 85% of the island is already a national park, so toxin drops could be massively effective in the uninhabited regions of the island.
“The habitat there is so unique and so much of it is truly a wilderness area,” explains Paul Norris, a stakeholder representative for Predator Free Rakiura and RealNZ Chief Conservation Officer.
“It is quite a diverse landscape, with a lot of rock around the coastal areas and a lot of big stands of trees. When you get up higher, there’s alpine areas and snow in the winter months.”
The size and diversity of the environment mean that without predators, it will again become a hot spot for native wildlife.
But as it stands, wildlife on the island is in trouble. Parts of the bush are collapsing, and bird and lizard populations are struggling along with it.
“Possums have eaten away the top vegetation,” Paul says.
“Trees have died. The floor covering has been eaten out by deer. The bush is in a very poor state. Not everywhere, but, as you can imagine, if they have devoured an area, they just move on to the next one.”
The pukunui (southern dotterel) is in dire trouble, too. Historically found across the South Island, but stoats, weasels, and ferrets proved deadly for the shorebirds. Now, only 101 of the birds remain, and all of them live on mustelid-free Rakiura. Unfortunately, the plucky ground-nesters are being devastated by feral cats. Their population has fallen more than 65% since 2009.
Hope on the horizon
Incredible birdsong can be heard around the township, thanks to a huge trapping effort from the local conservation group, Stewart Island/Rakiura Community & Environment Trust (SIRCET).
“They’re holding the line in that area, but certainly, once you get a kilometre from the township, the bush is pretty silent,” Paul says.
The wildlife around the town and inside the fenced Mamaku Point Conservation Reserve hints at what Rakiura could be without the predators that devastate the bush and birds.
“The dawn chorus here starts at about 4 am and is just loud. It’s just genuinely loud,” local resident and chair of SIRCET, Shona Sangster, explains.
“One of the things that still blows me away is quite often, I’ll see red-crowned kākāriki. They’ve had a couple of good summers, and they’ll be down on my driveway [foraging amongst] moss.”
The ground foraging is a show of incredible confidence from the species – confidence Shona believes comes from the reduction of predators.
“I think it doesn’t take some species, especially your smarter parroty type species, long to rejig their behaviour.”
Restoring the mauri of Rakiura
Tane Davis saw the immediate bounce back of birdlife on neighbouring sanctuary island Putauhinu, where he worked on the eradication of kiore in 1997, achieved through a toxin bait drop.
“Dramatic changes started to appear virtually within months. The island was starting to regain its mauri (life force).”
“The bird life starts to populate. The bird life becomes more relaxed.”
Tane represents Rakiura Tītī Islands Administering Body on the Predator Free Rakiura engagement and advisory group. To him, achieving a predator free Rakiura and being able to reintroduce kākāpō and tīeke would be huge.
“That’s the jewel. That’s the taonga. That’s the reward for our people.”
“The birds are a big part of us as Ngāi Tahu, and we are a part of them.”
Benefits that go beyond
A project of this size and complexity has never been attempted and will unlock new knowledge to achieve a Predator Free New Zealand.
“A successful eradication sets us up as a nation to truly contemplate a Predator Free 2050. As the third largest island in Aotearoa, a predator free Rakiura will show what is possible,” Department of Conservation Predator Free 2050 manager Brent Beaven says.
But the list goes beyond predator free aspirations, Brent explains. New job opportunities in the fields of ecotourism and biosecurity would be created on the island. The tourism potential of an island with kākāpō, kiwi and mohua is huge, he says.
“Stewart Islanders would be free of the nuisance of rats. Whenever there’s a rat plague on the island, residents can be overwhelmed by rats chewing wires in their boats and cars and destroying food.
“And without the impact of possum browsing, our native forests could be more resilient to climate change. As the world ramps up carbon markets, there is the potential for both economic and climate change benefits of being predator free,” Brent says.
Where the Predator Free Rakiura project will begin
The project is in its consultation and planning phase, and trials are underway. These include testing what lures attract the island’s three rat species.
The operation will fall into three main stages:
- Knockdown: in uninhabited areas, an aerial 1080 drop and bait stations wipe out 99% of target populations
- Mop up: surviving predators are detected and targeted
- Maintenance: reinforcing the boundary and managing incursions
Eradication is forecast to take six years, and operations are slated to begin in the uninhabited southern end of Rakiura.
