Two years ago, New Zealand launched a plan to reverse the decline of its native bird – to the point where 100,000 kiwi were scratching around our bush by 2030. Are we any closer? In the first of a two-part series, science reporter Jamie Morton looks at how close kiwi have come to the brink.

Amid South Waikato's gently rolling landscape, Sanctuary Mountain Maungatautari cuts an imposing figure.

The deep-green forest that surrounds this craggy, mist-covered mountain is as close to New Zealand's prehistoric wilderness as you're likely to get – and it's been carefully kept that way.

The 3400ha mountain and its 47km boundary remarkably stands as the largest pest-proof fenced project in the world, offering a rare mainland refuge for kōkako, hihi, takahē, kākāriki - and now - one little western brown kiwi chick named Tahi.

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Conservationists recently marked the 8-month-old bird's arrival with a pōwhiri, before carrying him up the mountain to his new home, a burrow shaded by a patch of fern.

As his name symbolised, Tahi was a first; not of his rare sub-species on the maunga, where about 200 already roamed, but of 500 more to be introduced there over the next five years.

The fortress has an estimated carrying capacity of 690 pairs of kiwi, and when it reaches half capacity – around 325 pairs – birds will begin to be moved off the mountain to begin populations in other predator-controlled areas.

That's why it's been chosen as something of a jump-off point for a national effort to turn the kiwi's 2 per cent annual loss rate into a 2 per cent annual increase.

In Tahi's case, Horowhenua residents Will and Jan Abel had bought a block of land near Raetihi and were surprised at how many kiwi lived on it.

When asked if they wanted to get involved in the national effort to save the birds, they jumped at the chance.

After seven years of learning about kiwi conservation and running a trapping programme with neighbours and Horizons Regional Council, the couple farewelled the first chick from their land to be part of the national programme - Tahi.

The egg, produced late last year, was uplifted from their block and taken to Otorohanga where it was hatched in January of this year, before spending six months at Rotokare Scenic Reserve.

Michelle Impey, executive director of the charity Kiwis for kiwi, said this bird represents a whole new approach to tackling declining kiwi populations.

"We have changed the way we're doing things in order to make the most of opportunities offered by others."

Using Operation Nest Egg, chicks hatched from wild-collected eggs will be incubated in captivity and released into existing predator-free habitats where they can breed in a safe environment.

"Once we have grown those areas near to capacity, we can then relocate some of the offspring to start new families in other places," she said.

"By increasing the supply chain and getting these kohanga kiwi sites to capacity more quickly, we can now do in five to 10 years what would have taken 50 years or more."

The strategy's success or failure depended on many groups – the Department of Conservation (DoC), iwi, private landowners, regional councils, hatching facilities and countless volunteers – all coming together for the cause.

Being able to stop the decline – let alone build the total kiwi population to 100,000 by 2030, as is the key goal of DoC's draft Kiwi Recovery Plan – would be a monumental feat.

A LEGACY OF LOSS

To understand why is to understand what has pushed down numbers to just around 70,000.

For millions of years, kiwi thrived in a well-suited, threat-free habitat alongside a multitude of other species now either lost or driven to the brink.

With millions of these birds scratching around in New Zealand's ancient undergrowth, it's difficult to imagine what the nocturnal chorus might have sounded like.

This picture began to change dramatically, of course, when human settlers first arrived.

The destruction reached a new level in the late 1800s, when mammalian predators introduced to control rabbits instead found a buffet of flightless birds that relied on camouflage as a means of defence - something not so effective against a ground-dwelling predator with a keen sense of smell.

When the scale of the massacre had been properly understood, it was estimated the population had fallen to 100,000, with an annual decline rate of 4 per cent.

While numbers had plunged further, DoC's response of establishing a network of five kiwi sanctuaries in Whangārei, Coromandel, Tongariro, Haast and Okarito eventually halved the loss rate.

The threat, meanwhile, remained much the same.

An average of 27 kiwi were killed by predators every week – driving a population decline of around 1400 birds every year.

Kiwi researchers' best estimates are that New Zealand's kiwi population was 67,550 in 2015 – that's fewer than the estimated 73,000 in 2008.

Their estimate was that, if the current management of each taxa was maintained for the next 15 years, the total kiwi population would be more or less stable.

Since 2000, population declines had been turned around for the four rarest - rowi, Haast tokoeka, Coromandel brown kiwi and little spotted kiwi - and reduced for others.

Jan Abel, left, owns the land where Tahi came from. Pictured with her are Craig Montgomerie, of Sanctuary Mountain Maungatautari, and Michelle Impey, of Kiwis for kiwi. Photo / Maddox Photography
Jan Abel, left, owns the land where Tahi came from. Pictured with her are Craig Montgomerie, of Sanctuary Mountain Maungatautari, and Michelle Impey, of Kiwis for kiwi. Photo / Maddox Photography

However, fewer than a quarter of New Zealand kiwi lived in places where predators were controlled.

More than three-quarters of kiwi didn't have this level of protection, so many populations continued to decline.

Across all 10 kiwi species, the proportion of each population under active management varied greatly, but generally, the smaller the percentage under active management.

The species with the largest number of birds under active management was the Northland brown – an estimated 4075 kiwi, nearly half of its population.

That with the smallest number actively managed is the Rakiura (Stewart Island) tokoeka – with just 250 birds out of an estimated population of 13,000, just 1.9 per cent.

Still, the size of individual kiwi populations wasn't precisely known because there wasn't yet a cost-effective way to count kiwi.

What was known was that the biggest threat the birds faced was being killed by pest mammals.

Simply put: protecting habitat without reducing the number of predators would not save kiwi.

Stoats and feral cats posed the biggest risk to chicks, while dogs and ferrets were a particular danger to adults.

"None of these have been eliminated from the 'list of most wanted' but of course in specific areas where there is pest and predator control, they are being eliminated or reduced," Impey said.

And many dog owners sadly remained oblivious to the deadly threat their animals pose to kiwi.

"The challenge is that some people are simply unaware – they don't know the harm dogs can do to kiwi.

"Some people know but don't think their dog would do it - and worse yet are people who know but don't care.

"I believe we just have to keep trying to have open, honest discussions and not create a sense of 'us vs them' with dog owners."

THE ROAD TO RECOVERY

DoC's draft 10-year plan, unveiled in October 2016, proved the first to assess the actual sustainability of current efforts, and to look beyond simply slowing or halting kiwi decline to actual growth.

Backed by a new $3.6 million programme, the DoC strategy further aspired to restore the national distribution of all species of kiwi and maintain their genetic diversity.

By 2030, DoC wanted species populations rebuilt to 35,400 brown kiwi, 35,000 tokoeka, 2900 little spotted kiwi, 19,900 great spotted kiwi and 900 rowi.

The cost of the work, estimated at a further $1.6m than what's spent annually, was being mostly met by an $11.2m bag of rescue money included in 2015's Budget, with an annual shortfall of $1.3m raised primarily by Kiwis for kiwi.

The plan was to work in step with wider efforts working towards the Government's goal of zero predators by 2050, coming with a separate investment of $28m, with around 100 community conservation groups playing a role alongside large-scale pest control operations.

Kiwis for kiwi's own national strategy, launched last year, focused on boosting the number of kiwi chicks in predator-free creches where they could safely grow and start reproducing, so their young could be moved to other predator-free areas to start new populations.

Its chairman, Sir Rob Fenwick, described it as like "setting up an endowment fund for kiwi".

With Tahi's exciting new life amid the bush at Maungatautari, it was already starting to pay off.

"The birds will flourish in a safe environment, the gene pool will be improved and this is a pragmatic and economically viable approach to putting a dent in the 2 per cent decline of kiwi," Will Abel said.

"There's nothing about this that doesn't make sense. While the land belongs to us, the project belongs to the wider team and the birds belong to New Zealand.

"We look forward to welcoming back Tahi's offspring in due course."

Who are Kiwis for kiwi?

Kiwis for kiwi is something of a one-stop-shop for the conservation of our national bird.

It raises much-needed funds to support dozens of community-led projects around the country and offers practical information for aspiring kiwi conservationists to kick-start new ones.

The national charity also regularly works with schools, bringing the cause into classrooms to inspire young minds.

Its executive director, Michelle Impey, said the exciting thing about its strategy – which complemented the work done by the Department of Conservation and so many others – was its potential to turn the kiwi's decline around.

"We can start growing kiwi numbers on the North Island within the next decade, for the first time reversing the decline that started when man set foot on Aotearoa," she said.

"The reason we want people to get excited about this is that it is unique in the world of conservation to have a plan that uses proven scientific methodology.

"This strategy is time bound, measurable and tangible and we can actually do it. This is a good new story in the making that we want New Zealanders to rally behind and help support."

And that support could take many forms.

"We are very fortunate in New Zealand that many people still have kiwi either in their backyard or close to where they live.

"So they can be actively getting involved - by doing predator control, volunteering at an existing Kiwi protection project, donating money and by controlling their dog, ensuring it never meets a kiwi and harms it."

Kiwi facts

• An average of 27 kiwi are killed by predators every week. That's a population decline of around 1400 kiwi every year, or 2 per cent. At this rate, kiwi may disappear from the mainland in our lifetime. Just 100 years ago, kiwi numbered in the millions.

• Stoats and feral cats posed the biggest risk to chicks, while dogs and ferrets were a particular danger to adults. A single roaming dog can wipe out an entire kiwi population in a matter of days.

• Around 20 per cent of the kiwi population is under management. In areas where predators are controlled, 50 to 60 per cent of chicks survive. In areas that aren't managed, 95 per cent of kiwi die before reaching breeding age.

• A survival rate of just 20 per cent of kiwi chicks is needed for the population to increase. That's been shown in the predator-controlled area of Coromandel, where the kiwi population is doubling every decade.

• By turning an annual 2 per cent decline into a 2 per cent increase, conservationists aim to lift the kiwi population from 70,000 to 100,000 by 2030.