Category: Islands

Source: Department of Conservation

Conservation for the critically endangered kākāpō dates back 130 years to 1894, when Richard Henry first moved kākāpō to (then) predator free Resolution Island. Today, DOC’s Kākāpō Recovery Programme combines the efforts of iwi, partners, scientists, rangers, volunteers, and donors to continue to protect and restore this taonga species.

Our purpose is to restore the mauri (life force) of the once plentiful kākāpō. So far, efforts have been rewarded and during nearly 30 years of the programme the population has increased from 51 to the 247 kākāpō alive today. It’s a long game with challenges that can be grouped into three main categories; habitat, genetics, and disease.

Kākāpō Advocacy Ranger, Andie Gentle, looks into the first challenge – habitat, and what it takes to find new sites for the growing kākāpō population.

Kākāpō pace

Aotearoa New Zealand’s much adored night parrots come with their own, unhurried pace. Longevity is on their side. The oldest kākāpō known today is at least 51 years old and it is estimated they could live between 60-90 years old. Many kākāpō reach their teens before they start successfully breeding and even then, they only breed once every 2-4 years.

Most of today’s 247 kākāpō live on two Southern predator-free islands which are reaching kākāpō-capacity. With each breeding season, there is an increasing need to find sites to support kākāpō populations into the future. To be suitable, sites need vast native forest, no predators (feral cats, rats and stoats) and the ability to stimulate successful breeding (more on that later).

Kākāpō-pace means each new site trial could take a decade or more to gather the information required. One long-term site trial that has recently been completed was on Te Hauturu-o-Toi/Little Barrier Island.

Hauturu & kākāpō

There are only two pest-free islands in New Zealand large enough to sustain a population of kākāpō that are certainly beyond the swimming distance of rats and stoats. One of them, Whenua Hou/Codfish Island, is a successful breeding home to a population of nearly 100 kākāpō. The other is Te Hauturu-o-Toi/Little Barrier Island.

Hauturu is a sanctuary 80km north-east of Tāmaki Makaurau/Auckland. It was New Zealand’s first nature reserve and is now a refuge for hundreds of rare and endangered plants, birds, and animals.

Kākāpō were first translocated to Hauturu in 1982. At the time, there were just 29 known kākāpō and it had become clear that they were being predated by cats on Rakiura/Stewart Island. With the presence of kiore (the Pacific rat) but no feral cats, Hauturu was identified as a safer haven. By the end of 1982, 21 kākāpō had been relocated there. Intensive management and supplementary feeding programmes began seven years later after no breeding had occurred on the island.

Breeding triggers

The only known trigger to stimulate kākāpō breeding today is the mast of the rimu tree. This happens once every 2-4 years on the Southern islands. We can predict a mast in advance by comparing seasonal temperatures year-on-year and counting fruit tips.

To best support the critically endangered kākāpō we supplementary feed them ahead of a breeding season to help them reach top breeding condition. Additional feeding for chick rearing is also required if the mast was big enough to stimulate breeding but didn’t result in enough fruit to sustain chick rearing (which may occur after storms or extreme weather events or if the fruit doesn’t ripen).

Despite the absence of rimu on Hauturu, several breeding attempts were made there in the 1990’s and two chicks were raised with supplementary feeding support. It was the kauri tree that was thought to be the most likely trigger to stimulate kākāpō breeding on the island. Regardless, this was proof that, with support, kākāpō could thrive on Hauturu.

There was just one big problem. The island’s terrain is much more extreme than the Southern islands, making this level of hands-on management logistically challenging.

The rugged terrain of Hauturu, being navigated by DOC rangers and Auckland Zoo team members as they carry out work with kākāpō on the island | DOC.

By 1999 more kākāpō had been discovered on Rakiura and the total population numbered 63. All kākāpō were returned South to help diversify the precious breeding populations that were now active on Whenua Hou and Maud Island. Following the removal of kākāpō, kiore were eradicated from Hauturu and the sanctuary gained pest-free status in 2004.

The trial

With supplementary feeding successful but not feasible on Hauturu, the next step was to learn if kākāpō could breed and raise chicks there without support. In 2012, eight of the total 125 kākāpō at the time were carefully selected by their genetic profiles and breeding history to help us find out. Over the coming years another nine joined the trial.

Seven of this cohort had been on Hauturu before. Notably, all seven returned to their old home ranges on the island within a couple of weeks of arriving back. Two of the returning birds were super-breeders Blades and Flossie, who had each produced the most offspring by a male and female respectively at the time.

What did we learn?

Unfortunately, the next decade saw limited breeding success on the island. In 2014 Heather was the only female to nest. She only hatched one of three fertile eggs herself and that chick needed support as, by ten days old, it was starving. It was the same poor result in 2016 when Heather and Lisa nested and the only chick to hatch also required support due to lack of food. Lisa nested again in 2021, but her two eggs were infertile.

During the trial period of 12 years, the kauri tree did not produce a heavy crop of seeds as it had in the past. Along with the poor nesting outcomes, this confirmed that while Hauturu is safe for kākāpō, they are unlikely to be productive on the island without supplementary feeding.

Wrapping up the trial

In 2023 it was decided that the kākāpō on Hauturu would be more valuable back on the Southern breeding islands, and the plan is for all to be returned by the end of this year.

It may not be the last time kākāpō live amongst the Hauturu forest, so remnant of primeval New Zealand. Given the long lifespan of kākāpō and the size and pest-free status of Hauturu, the island could play a role in the future security of the population until other safe breeding sites become available.

For now, the island has helped provide valuable data and insights to help manage kākāpō conservation for decades to come.

Left: DOC Ranger Richard Walle. Middle: Jasmine from Auckland Zoo carrying kākāpō before the first transfer off Hauturu, 2023. Right: DOC Ranger Dani completing a transmitter change and health check on Flossie in 2023. All photos by DOC.

It takes a village

DOC’s Kākāpō Recovery team worked closely with iwi (tribe) representatives from Ngāi Tahu and the Ngāti Manuhiri Settlement Trust to undertake the trial and the required transfers of the manu between rohe.

Kākāpō are a taonga species to Ngāi Tahu, the principal Māori iwi of southern New Zealand. It is of great significance to iwi when the care and protection of a taonga is transferred. During the Hauturu trial local mana whenua Ngāti Manuhiri took on kaitiaki responsibilities of the manu through the tikanga of whāngai (the concept of fostering).

This trial was undertaken in association with Auckland Zoo Conservation Fund with practical assistance from Auckland Zoo staff and its vet hospital, the New Zealand Centre for Conservation Medicine. It was also supported by Kākāpō Recovery Programme’s National Partner Meridian Energy and DOC’s National Partner Air New Zealand.

Ngāti Manuhiri and Ngāi Tahu representatives with DOC team members during (left) the first transfer from Hauturu to Fiordland in July 2023, and (right) the second transfer in August 2024. The final cohort of remaining monitored kākāpō on Hauturu will return later this year | DOC.

Moving forward to step back

Two new site trials are underway at Sanctuary Mountain Maungatautari in Waikato and Coal Island/Te Puka-Hereka in Fiordland, and there are more to come. Like at Hauturu, it will be years before results are known, but it is hoped that more breeding triggers could be discovered along the way.

The last three breeding seasons have been bumper on the Southern islands. The next breeding season is predicted to be 2026 and with more than 80 breeding-aged females, it could be the biggest yet.

Rakiura will be a game changer for kākāpō when it becomes predator free. From there, the goal will be to one day return kākāpō to all their natural ranges throughout New Zealand. Of course, these visions will rely on the success of the country’s predator free movements.

We’ve come a long way since 1894; just imagine Aotearoa after another 130 years of care and protection. Will kākāpō be roaming safe and free among our great-grandchildren?

Anything is possible, even when each day goes at kākāpō-pace.

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