How do you rebuild a population from one island?

The program started with a small number of wētā collected on Little Barrier Island to seed a colony at Butterfly Creek, a visitor attraction near Auckland. Staff there established early husbandry and release techniques — in plain English, the methods for keeping the insects alive and healthy in captivity and setting them up in the wild.

The founding colony produced the first release animals, which went onto two Hauraki Gulf islands, Motuora and Tiritiri Matangi, in 2010 and 2011.

In 2012, Auckland Zoo joined with a second breeding colony. The zoo refined the Butterfly Creek techniques and, as the paper puts it, "industrialized" them, rearing wētā in communal nurseries at a scale that produced 8,874 insects for release between 2014 and 2025 alone.

Releases expanded to multiple predator-free islands in the Hauraki Gulf and Bay of Islands, and most recently to two mainland fenced sanctuaries north of Auckland — areas enclosed by predator-exclusion fencing.

Did the released insects actually survive?

Intensive monitoring on Motuora and Tiritiri Matangi shows at least four generations of wētāpunga have now been born on those islands. Internationally, that generational benchmark is recognized as confirmation that the species has established self-sustaining wild populations on both islands. Many of the other island populations are also well on their way to the same milestone.

That result matters because breeding and releasing animals is only half the battle. Conservationists also need evidence that released populations persist without continued human help.

Who made it work?

The paper credits a wide network of partners:

• Ngāti Manuhiri, the Māori tribe that is kaitiaki (guardian) of wētāpunga and mana whenua — the traditional tribal authority — over Little Barrier Island, where the founding insects came from. Wētāpunga are a taonga, or treasured, species for Ngāti Manuhiri, and the iwi provided ongoing support and engagement.
• Butterfly Creek and Auckland Zoo, which developed and scaled up the breeding methods.
• Community restoration groups across the upper North Island, which raised funds for the resource-hungry intensive management of the insects and helped organize releases and ongoing monitoring.

"The expertise, commitment and collaboration of many people and organizations contributed to the recovery of this iconic giant wētā," Green said.

What comes next?

Green argues that documenting the program matters beyond the wētāpunga itself. "By documenting this amazing conservation success story, we can share valuable knowledge on husbandry, release methods and population persistence," he said.

That knowledge is already being applied elsewhere. It is now informing breeding of the Māhoenui giant wētā at the Ōtorohanga Kiwi House. Green points to other candidates for similar programs, including the Canterbury knobbled weevil (Hadramphus tuberculatus) and several native stag beetle species.

As for the insect at the center of it all: "The future of wētāpunga is looking bright," Green said.

The peer-reviewed paper, by Chris Green and colleagues, appears in the New Zealand Journal of Zoology (2026), DOI: 10.1002/njz2.70061. As with any single case study, the findings describe one species and one program; the authors themselves frame it as a knowledge-sharing exercise rather than a guarantee that the same approach will work for every endangered invertebrate.