A rocky outcrop on Antipodes Island A rocky outcrop on Antipodes Island

There used to be a lot of places that looked like this, but now there's only one: a volcanic slab of rock in the world's roughest sea, which has become our southern conservation fortress.

There are no trees, only fields of dense, sepia-toned tussocks, dotted with giant birds and their nests; no gorse and broom, only native plants like mosses and lichens and tall, spindly ferns that droop in the wind; sea mammals and penguins and tiny meat-eating parakeets together in what seems like a living laboratory, a range of travelling species accidentally assembled in a world without land mammals.

For a long time, this tiny place was undiscovered, and its wildlife prospered. It's further from the former centre of western civilisation than any other landmass, but it was eventually found and kept secret, which changed its character.

For much of the last century, the sub-Antarctic islands as a whole were forgotten, but they have since been rediscovered as something aspirational: a glimpse of the world as it used to be, and something that can be recreated.

In a time where the idea of a country without introduced predators is increasingly both politically and scientifically feasible, the wild islands of the south have been given a new sense of value. Can the damage to these places be undone? And if so, can we do this on a wider scale?

A recent expedition to the most remote of the sub-Antarctic islands will get us closer to answering those questions, and forms an important stepping stone in our latest New Zealand project, repairing the ecological damage wrought over several centuries.

But there remains another question: Is it too late to save what's left?

ACROSS THE SEA

The HMNZS Wellington sailing in rough seas to Antipodes Island

The HMNZS Wellington sailing in rough seas to Antipodes Island

The ragged sub-Antarctic islands south-east of New Zealand, on the wind-battered path to Antarctica, are our equivalent to the Galapagos Islands: one of the world's few remaining pockets without an active human presence, and where hundreds of species, many of them found nowhere else, live largely untouched.

The sub-Antarctics have been called the seabird capital of the world due to the swathes of birds roaming the skies of the Southern Ocean, which rest on the small, rocky islands to breed. It's for that reason the islands were deemed internationally significant and given World Heritage status, which they share with the pyramids and the Great Barrier Reef.

The most remote of the five island groups is the Antipodes Island group, comprising six small islands and the largest, Antipodes, in the centre. It is roughly 860km south-east of Stewart Island. It is ringed by severe basalt cliffs, punctured with caves hollowed out by the sea, and much of its surface comprises a thick, green plateau that rises to a volcanic peak. It is often doused in rain or obscured by mist, which gives it a passing resemblance to King Kong's Skull Island, a strange and imposing presence emerging out of nowhere.

The island was called the Antipodes because of its location: It is geographically further from London than any other landmass on Earth. Similarly, its Māori name, Moutere Mahue, roughly means the forgotten islands. Even today, it is extremely difficult to reach, with two shallow and rocky landing points only accessible by a small boat moving fast enough not to be swallowed by forests of bull kelp, but not too fast so as to crash on the shore, or into a passing elephant seal. One of the nearby islands, Leeward, is so rugged no human has set foot on it, due to the sheer cliffs and impossible conditions that make a helicopter landing dangerous.

The volcanic landscape has been carved by the conditions of the Southern Ocean, one of the fiercest places on Earth. The island straddles the “roaring forties” and the “furious fifties”, referring to the southern latitudes in which westerly winds prevail, which has left many shipwrecks in its wake.

What has made the island so hostile to humans has allowed wildlife, particularly seabirds, to flourish.

Everything that made it to Antipodes Island, which is a relatively small 2000ha, got there accidentally.

In geological terms, the island is brand new, volcanically formed on the edge of the Bounty Plateau, the huge underwater mass south of New Zealand that forms part of Zealandia, the ancient continent.

The island has 21 species of seabird, four species of ground bird, and hundreds of species of plants and invertebrates, with a high degree of endemism (meaning species found nowhere else).

Because it is so remote, the birds were likely carried there by the wind, which has resulted in an unusual conglomerate of species. Antipodes Island is one of the only places in the world with endemic species of both parakeets and penguins, which happily co-exist with elephant seals, snipes, giant petrels, and albatrosses.

Because there are no trees, the parakeets - of which there are two species on Antipodes, both likely related the mainland's Kākāriki - burrow in the ground. They also eat meat, in the form of dead penguins.

That two distinct types of parakeet, typically a tropical species, are endemic to one small sub-Antarctic island is unusual in itself; even stranger is that in their 30,000 years on the island, there has been no evidence of inter-breeding.

Despite their island fortress, many of the species found on Antipodes are in decline.

They include some of our most fascinating birds, and invertebrates that are entirely unique: An expedition to the island in 2000 found nine species never before recorded by science.

Islands make up a disproportionate amount of the world's biodiversity, but are also the most vulnerable to endangerment. Around two-thirds of recent extinctions happened on islands, according to 2017 research.

The reasons for the declines are different for each animal, but in most cases, the causes can be traced back to the ultimate alien invader: Us.

THE LAST ALBATROSSES

The polar bears of the south face extinction

Wandering albatrosses perfoming an elaborate mating ritual.

Wandering albatrosses perfoming an elaborate mating ritual.

When Kath Walker and Graeme Elliott first arrived on Antipodes Island in 1995, they thought it was paradise. It was warm and sunny, like a mirage in the bleak Southern Ocean.

“It was like a tropical island," Walker says.

“We had really hot, sunny weather that year. Even though we’ve been all these other times since, that first time…"

The scientists have been to the island every year since then, spending much of each summer observing an interesting and under-observed bird species, the Antipodean wandering albatross, one of the world's largest flying birds.

As its name suggests, virtually the entire species breeds on Antipodes Island, where the birds carefully build their nests in the open tussocks high above the sea, on the volcanic slopes rising to the cratered peak.

Across the island, males wait in the tall grass for passing females to stop by so they can perform their elaborate mating rituals, composed of squawks, roars, and beak clapping.

Of all the species on the island, the albatrosses are in the most dire straits. They are critically endangered, and at their current rate of decline, the species will be functionally extinct within two decades - another of our native birds lost forever.

"I’m always thinking our wandering albatross should be New Zealand’s polar bear," says Kath Walker.

"We’re seeing trouble, and they’re beautiful and interesting enough that we should focus on them as a canary in a goldmine."

Walker and Elliott, who both work for the Department of Conservation (DOC) but study the albatrosses on their own time, have spent more days on Antipodes than anyone else. Because the albatrosses have such a long life-span - they can live up to 60 years old - some of the birds they met on their first expedition are still around.

Much of the scientists' work is done during their annual leave, and at times they've spent their own money to make the arduous trip across the Southern Ocean.

They started studying the albatrosses in 1995 because of the declining population, which at that point had fallen to around 5000 pairs, but was starting to reverse.

"The birds are pretty flash - they’re special," Elliott says. "You see these magnificent creatures and you hear their population’s declining and that certainly wound us up.

"They were going up nicely, then in 2005, the population just crashed. The big thing we’ve observed is this crash from 2005, which in Antipodes hasn’t stopped."

There are now only around 2500 pairs, which, based on current rates, will fall to 500 pairs in 20 years.

The island's DOC hut, built in 1978, is above a cliff by the sea.

A pair of Antipodean wandering albatrosses performing a courtship ritual

A small outhouse near the DOC hut.

Climbing a hill covered in tussocks.

A parakeet endemic to Antipodes Island. Because there are no trees, they burrow on the ground.

Erect-crested penguins are only found in the sub-Antarctic Islands.

Climbing up the rugged slope above the island’s only DOC hut, which is perched close to a cliff overlooking a rocky cove, Walker and Elliott reach a long, flat plateau covered in squawking white dots.

Almost all that remains of the entire species breeds here, in this field.

The males wait patiently for passing females, which stop between each nest to perform their synchronised rituals, like a form of speed dating.

Many of the birds are young - they typically start breeding aged 10, and usually mate with the same partner for life - which makes the prospect of population recovery even harder.

Today, there are few females. The male albatrosses wait alone.

"You see the white birds standing around, which are males, trying to attract the females, of which there are none," Walker says.

"There is a huge sex imbalance."

The imbalance is so significant that male albatrosses, usually hostile to each other, have formed pairs, sitting closely next to each other and performing courting rituals. Some male pairings have lasted multiple seasons, a behaviour never seen before in the species, Walker and Elliott say.

The population problem, in the most basic sense, is caused by fishing.

Over the last decade, the albatrosses have been going further away to feed due to a change in local ocean conditions, likely relating to climate change, fishing practices, or some mixture of the two.

Because the albatrosses are frequently killed as bycatch by longlines attached to fishing boats, their new feeding destination - in international waters north and east of New Zealand - makes them vulnerable to poorly regulated fishing industries, like those of China and Chile.

The females, which are lighter and smaller, have been going further away to feed, into dangerous territory.

"Ten years ago, they never went to Chile," Walker says. "Now they all do."

Because so few scientists visit Antipodes, Walker and Elliott have become the defacto experts of the island.

Many of the notes scrawled on the walls of the hut are theirs, as is much of the crockery. They even discovered some of the historical artifacts left by the sealing gangs, on the edges of caves few people have ever visited.

The pair are often the only ones on the island, for weeks at a time.

When they arrived in 2014, they found much of the island had been damaged by landslides, including the hut, which had been shunted several metres onto a precarious angle above the cliff.

They spent six weeks in the castaway depot, the first people to stay there for a significant period of time since the castaways of nearly a century before; when their work was complete, they started digging out the damaged hut.

"The weather’s always crap, and the boat trips are usually pretty crap and scary," Walker says.

"The work’s repetitive, and it always means you miss out on summer in New Zealand. We’ve been missing summer for a quarter of a century. So there’s lots of downsides."

When they were dropped off in 2004, for example, the boat radioed the next day to say Walker's father had died. She was unable to make the funeral. Before her sister died of cancer, she wasn't around much because she was on the island: "We’ve missed life," she says.

But if it wasn't for them, the fate of the albatrosses would likely have gone undocumented and unnoticed. That's partly why the albatrosses' ongoing decline has been so frustrating - they feel powerless to stop it.

"We’re feeling voyeuristic, really," Walker says "We’re just watching this decline without being able to do anything about it."

It now seems the only way to stop the extinction of our southern polar bears is through international diplomacy, to force countries to regulate their fishing industries to reduce bycatch - a compromise that seems impossible.

Then there's climate change, which presents its own threat to animals reliant on the sea, particularly in the Southern Ocean which scientists believe is more vulnerable to acidification due to its cold water temperatures.

"To imagine it will change and get better seems a little on the optimistic side," Elliott says.

"If we’re experts at anything, it’s pissing around with albatrosses. It's not international diplomacy."

A penguin colony on Antipodes Island.

ROCKY REFUGE

A seal family near a penguin colony on Antipodes Island.

A seal family near a penguin colony on Antipodes Island.

One of the most interesting stories of the sub-Antarctic islands is a useful lesson in contrasts.

The Auckland Islands make up the largest bloc in the sub-Antarctics, primarily through the main island, which is 23 times the size of Antipodes.

It has been ravaged by introduced pigs, cats and mice, which have been disastrous for the native species. They have wiped out all of the burrowing seabirds, and albatrosses don't breed there - The unique megaherbs, which at their best look like something out of Dr Seuss, only grow a few centimetres tall.

It is the conservation equivalent of a scorched earth. But travel a few hundred metres south, and you find the opposite: Adams Island has been largely untouched by humans and introduced animals, and has flourished.

It is abundant with native birds and plants, despite being a short distance from an island heavily damaged by introduced predators.

It's the reason why Antipodes Island has recently been the focus for conservation efforts: If nothing is done, it could become Auckland Island, but with intervention, it could become Adams Island.

It doesn't have the same predators as Auckland Island, but incredible damage is being done by the one land mammal living on Antipodes: Mice.

Getting rid of the mice on Antipodes has been a long-held fantasy for conservationists.

Ever since mice arrived on the island, likely hitchhiking with a sealing gang or escaping from a shipwreck, they have wrought havoc on the its delicate ecosystem. They feed on invertebrates, so are well nourished by the dozens of species endemic to the island, ranging from beetles to spiders to cave weta.

At least two species are believed to be locally extinct due to mice, including the weta species. At least two more are on the brink of extinction.

Because the mice vastly outnumber everything else, they form an imposing bloc against the birds, which eat the same invertebrates.

The distinctive tussocks of Antipodes Island can grow a metre high.

The HMNZS Wellington waiting offshore of Antipodes.

The island's DOC hut was built in 1978.

A penguin infiltrates a seal family.

A fur seal and giant petrels intermingle on the shoreline.

The operation, called Million Dollar Mouse, had a strange path to fruition: The majority of the cost was borne by DOC, but the rest was met through a public crowd-funding campaign supported by the Morgan Foundation, with help from other charitable groups.

The work began before the former National-led Government announced its intent to eliminate predators from mainland New Zealand by 2050, but is now seen as one of several crucial stepping stones: New Zealand has a prodigious record of killing rats, but strangely enough, has limited experience in killing mice.

Several other sub-Antarctic islands have been cleared of predators, but the Antipodes operation is the hardest yet.

It's in large part due to the conditions - it's too far away to fly, so helicopters had to be brought over in a large ship and stored in a temporary hangar erected on the island, where miserable winter weather made flying hazardous. But it was also the nature of mice themselves that made the operation difficult, because they are extremely hard to kill.

"Mice have incredibly small home ranges" says Finlay Cox, who is leading the monitoring effort.

"If we did miss some individuals, it would be incredibly difficult to know that at the time."

Every predator has what is known as a home range, which is effectively the radius in which an individual animal moves in its day to day life.

A wild cat’s home range, for example, can be up to 500ha; a stoat’s range is around 200ha; a possum or a rat’s can be up to 2ha.

On Antipodes, research showed a female mouse’s home range was just 20m, which meant no corner of the island, including the steep cliffs and the inter-tidal areas, could be spared.

Because mice are king, if any survived, they would just breed again and repopulate. It's why officials waited two years after dropping the poison to come back and see if it worked - if any mice survived, they would have reproduced again.

"On Antipodes, they’ve got no competition or predation from rats, in fact they’ve got no predation from anything," Cox says.

"They’ve got this harsh environment to survive in, but there are no predators reducing them."

A land ruled by mice can be frightening. A grimy, night-vision video from another island shows a gang of mice killing and eating an albatross chick many times their size, an unusual case of direct predation called a "prey swap".

It is effectively what happens when mice eat their way through the beetles, the snails and the other invertebrates and resort to eating birds: an ominous glimpse of the future if mice had remained.

If the mice weren't cleared from Antipodes, it would have spelled doom for many of the species there. While the focus is often on birds, there are hundreds of species on the island threatened by the tiny, alien invaders.

"The project was done to benefit the whole ecosystem there," says Stephen Horn, the project's manager.

"These islands are high value, they’re World Heritage sites, and part of the reason is they have this obvious evolutionary process with lots of endemism."

It has been an enormous logistical challenge to clear such a remote place of hundreds of thousands of mice. It involved transporting three helicopters and two diggers by ship across the Southern Ocean, building a temporary hangar on the island, and a team living there for several months in wild, wet conditions.

Helicopters landed on islands no human had ever landed on before, just to make sure there were no mice there that could reinvade; there is no harbour, so ships travelled back and forth for thousands of kilometres, while machinery was offloaded.

"It’s one of those things where if you start writing an acknowledgments list, there’s a cast of hundreds, throughout the department and external," Horn says.

"You can’t put it down to a few people, it’s a massive team effort to get this kind of thing done."

It will all lead into the next step - clearing the ravaged Auckland Island of predators, the last remaining sub-Antarctic island with predators.

Birds flying above Antipodes.

A penguin sleeps.

REDEMPTION

On an Autumn's day in 1800, a British naval ship, emerging from dense fog, came across Antipodes Island, a previously unmapped slab of rock. They found a place heaving with wildlife, and a seemingly unlimited bounty.

In the years after its discovery, sealing gangs in their dozens arrived to hunt. At its peak, nearly 90 sealers packed the desolate island at one time, slaughtering seals in their thousands. In the space of just two years, around 350,000 native fur seals were killed, primarily by being clubbed in the head or stabbed with spears.

The extermination at Antipodes, just a few years after its discovery, amounted to roughly one third of all fur seals killed in New Zealand. The sea became so barren seals have only recently shown signs of recovery. Two centuries later, the fur seal population at Antipodes is still a fraction of what it once was.

By the 1860s, when there were no seals left, hunters briefly killed the endemic erect-crested penguins, which were were used for women's earmuffs and gloves in London.

Thousands of penguins were killed before it was realised the demand wasn't high enough to sustain an industry. Large rolls of penguin skins were left in a cave on the island, and remained there more than a century later.

Today, the penguins, much like the albatrosses, are in the midst of a stark decline.

Around two-thirds of the world's erect-crested penguin population breed on Antipodes. Little is known about the species, except that they are large, with flamboyant yellow eyelashes and booming voices.

They are one of two penguin species on the island, the other being the rockhopper. Both species have declined rapidly in recent decades. A recent count estimated the population of the two combined had fallen nearly 75 per cent since 1978, and both appear to be firmly on the path to extinction.

Like the albatrosses, the fate of the penguins seems unavoidable. The series of human-caused events - ocean acidification, overfishing, predator introduction - has caused so much damage it may be impossible to claw it back.

A TVNZ documentary about Antipodes Island, filmed in 1981, was titled "Island of Strange Noises" - it begins with frightening, disembodied squawks, like an introduction to an alien world.

The island itself looks extraterrestrial, in part because there are no trees, only enormous, green tussocks on old lava flows, littered with flying birds the size of pelicans and black and white penguins in their hundreds affixed to rugged brown cliff faces.

After they were plundered, and the sub-Antarctic Islands were forgotten, it seemed unlikely they would attain the status they have now - among the world's most fiercely protected places.

"It defies expectations, this place," says Conservation Minister Eugenie Sage, who visited the island with the monitoring group.

"Just listening to the seabirds and their chatter all night - it's not something you'd hear on mainland New Zealand, but it was something that was once on mainland New Zealand."

The idea that places like this can be saved is a relatively new one, and one New Zealand has been particularly good at pursuing. It's had more successful pest eradication projects on islands than almost any other country, and its methods are being used internationally as best practice.

The idea that places like this can be saved is a relatively new one, and one New Zealand has been particularly good at pursuing. It's had more successful pest eradication projects on islands than almost any other country, and its methods are being used internationally as best practice.

"I think New Zealanders really want to see some of these most remote, far away places kept as far as possible in their original state," Sage says.

"Aotearoa New Zealand is the seabird capital of the world, with a range of different species here. We need to protect all of the places they live."

In the coming weeks, it'll likely be confirmed that no mice remain on Antipodes Island, more than a century after they first arrived.

There are already signs of recovery; more snipes and more parakeets bouncing through the tussock than previous years.

In the quest to clear New Zealand of predators, there are much greater challenges ahead. For now, the many species living in this particular conservation fortress will thrive, for the first time since they were found by humans.

"With mice gone, they’ll do completely fine, they’ll have a great time out there," Stephen Horn says.

"They’re not competing with mice anymore. It will benefit a huge number of species."