Stephen Belcher

Great Experimentations

This year, the Department of Conservation will embark on a brave new model for managing takahe, one of New Zealand’s most endangered birds. After more than six decades of intensive intervention, rangers are going to try to do the impossible: nothing.

Written by       Photographed by Stephen Belcher

At this cold and early hour, as the boat skims across Lake Te Anau, the water surface is so still that Centre Island appears to float like a mirage, a perfect green disc against the metallic silver lake, the land and its reflection merged into one.

“Couldn’t ask for a better day,” says takahe ranger Martin Genet, holding the wheel with a hand pulled back into the sleeve of his down jacket and looking up into the heavy overcast sky. “I hope this cloud cover hangs on for the morning. It’ll make the climb easier.”

I know he is covering his unease with this small talk of the weather, feeling the pressure of leading someone to find one of New Zealand’s rarest birds. “We may not see any,” he cautioned me earlier. “They’ve become so wary of people, they hoof it into deep cover at the slightest disturbance.”

The cloud will burn off soon enough, but for now, as we dock at the Glowworm Caves wharf and start up the steep trail up and across a forested side of a gorge at the foot of the Murchison Mountains, we are grateful for the shade and coolness it provides. The mountain beech forest around us is silent, misty and mysterious, cut through with bands of limestone and pocked with caves and grottos.

Lake Orbell in Fiordland’s Murchison Mountains is ground-zero for the only wild takahe population on the mainland. It was here that Geoffrey “Doc” Orbell rediscovered, captured and filmed the birds that until 1948 had been considered extinct.
Lake Orbell in Fiordland’s Murchison Mountains is ground-zero for the only wild takahe population on the mainland. It was here that Geoffrey “Doc” Orbell rediscovered, captured and filmed the birds that until 1948 had been considered extinct.

Three steep and sweaty hours later, above the gorge and the clouds now, we cross the river over a natural bridge of jammed boulders and top the crest of a hanging valley, its floor filled with a long and shallow lake. There, on a narrow strip of a beach, imprinted in sand as golden and coarse as coffee sugar, is a set of fresh footprints. Genet’s mood lifts instantly.

“They’re here,” he says, then with his raised hand silences my reply. “Listen!”

With the stillness of the mountain valley surrounding us like an amphitheatre, not a breath of wind marring the mirror surface of the lake, we hear a deep Ooom Ooom. A sound so soft and faint it is impossible to pinpoint its source.

“There’s one! Just left of that big hebe bush.”

Genet’s voice is both excited and relieved. Some 50 m away, poised against a straw backdrop of tussock and watching us with its head cocked to one side, is an adult takahe. Off to the right and below, I spot its mate, frozen in the same vigilant attitude.

Up close their feathers have the iridescence of a polished paua shell, their carmine beaks marbled with shades of red, but from this distance the birds appear inky blue.

For a moment, we watch each other, then, with a couple of quick steps, both birds vanish under the tussock, into a grassy thicket riddled with tunnel-like trails. We would not see them again, but their image lingers in my mind like I had just stared into a lamp. This is my “Doc Orbell” moment, rediscovering for myself the takahe in the wild.

Despite more than three decades of Herculean effort to save the takahe, the number of birds in the wild have not significantly increased. Their gene pool is perilously limited, but with several small populations on predator-free offshore islands, takahe are no longer in danger of extinction.

In April 1948, on the very same beach of the lake that was to be named after him, Geoffrey “Doc” Orbell, an Invercargill doctor and avid deer hunter, found a set of bird footprints not unlike those of a white heron but with the big toe distinctly bent inwards. He had heard their calls, “as if someone were whistling across the top of an empty .303 cartridge”, and was convinced that the takahe, for so long thought extinct, was to be found here still.

In November that year, he returned to the valley and captured and filmed the bird. His discovery made headlines around the world. It was like finding the extinct dodo, alive.

In 1998, as the 50th anniversary of the event neared, I visited the Murchison Mountains to write the definitive story about the takahe for this magazine. I spent time with Doc Orbell, hearing his first-hand recollections. (He passed away in 2007, aged 98.) I flew around the Takahe Special Area with the members of a recovery team radio-locating the birds, waited out a two-day snow storm while we camped in the remote hanging valley, and assisted in the release of hand-reared juveniles into the wild. I depicted the population of takahe as a “lost tribe”, like the near-mythical Hawea people, a rebellious sub-tribe of the Ngati Mamoe who also sought their last refuge in the Murchison Mountains. Now I was revisiting the birds and their home range, curious to find how they were faring, especially on the eve of the great takahe experiment.

[Chapter Break]

Back in 1998, there were nearly 200 birds and the prospects for survival of the species were good. Burwood Bush Rearing Unit near Te Anau was a sort of takahe factory, producing steady numbers of ready-to-release juveniles from surplus eggs collected in the wild. Another 50 of the birds were protected on predator-free offshore islands such as Mana, Kapiti, Maud and Tiritiri Matangi, genetic safety caches should a disaster strike and wipe out a part of the Fiordland population. Still, when it came, the disaster took the recovery team by surprise.

“In 2007, we were about to celebrate our 300th takahe,” Phil Tisch, the programme’s manager, told me. “Then there was a beech-mast season…”

The fruiting of beech trees is what once induced breeding behaviour in the kakapo, and among trout fishermen it is eagerly
anticipated and known as the “mouse year”. The event, which occurs once every few summers, produces a rainfall of tiny nut-like kernels. This abundance of food commonly triggers a plague of mice and rats, a proliferation of prey which in turn stimulates the breeding cycle of stoats, which can withhold a pregnancy until conditions are most suitable. The following year, when most of the beech mast has either been eaten or is germinating, there is a sharp decline in the rodent population, while stoats remain numerous. In the absence of their traditional prey, stoats turn to birds. In the Murchison Mountains these happen to be the takahe.

“The beech mast was not particularly heavy but it coincided with a harsh winter and already high predator numbers. As a result, our bird population was knocked from 160 to 90,” said Tisch. “We’re still recovering from this setback.”

As with most of our flightless birds, the task of saving the takahe is mainly a battle to control the stoat. It has been thought that an adult takahe can stand its ground against this super-predator, though a stoat certainly would not be shy of attempting to take the bird down.

takahe_rescuechopper

I have seen a stoat attacking and killing a fully-grown rabbit with leisurely ease. It is a gruesome spectacle to behold, and harder still to listen to. The stoat bites the rabbit at the back of the neck and for a few moments the two are a blur of tumbling, knotted bodies. The killer then backs off, nimble and poised, to watch from a safe distance as the rabbit, perhaps already partly paralysed, continues to tumble about, squealing in legless agony. The stoat darts in for another bite and backs off again, preventing any escape but not administering a coup de grâce. Each time I have witnessed this, I have had to remind myself this is Nature’s way. But I have wondered what odds a takahe would have in a similar situation.

Martin Genet, who is responsible for the takahe habitat, shows me a topographical map of the mountains so covered with black dots it is difficult to see any other features. The dots, 200 m apart on ground level, represent wooden tunnel traps—each with entrances at both ends, two spring-loaded jaws and an egg for bait in the middle. They are strung into long traplines following the contours of the land: ridges and spurs, valley floors and especially the shoreline of the lake.

In total, there are 1600 traps spread over 500 sq km, monitored regularly by a team of contract trappers who carry with them trays of fresh eggs to replace the bait. At times, a trap yields a double hit, as one stoat does not hesitate to eat another already immobilised by the sprung metal jaws. In a year, the traps may take out 250 to 350 stoats.

Recent technological advances in the battle against stoats may tip the balance of survival in favour of the takahe and other native birds. The Auckland-based company Connovation has designed a stoat-specific toxin known as PAPP (para-aminopropiophenone) which works by inhibiting the animal’s red blood cells from carrying oxygen, with effects similar to carbon-monoxide poisoning. Connovation claims its field trials in Southland’s Waitutu Forest showed an 80 per cent reduction in stoats.

Another company, called Goodnature, based in Wellington, has developed a range of self-resetting traps targeting stoats, rats and possums. These are powered by compressed carbon dioxide from a recyclable canister and are toxin-free and species-specific. When the stoat brushes aside a trigger to investigate the bait behind it, the trap releases a steel-core, glass reinforced polymer piston, delivering a precise and fatal blow, then resets itself. Up to a dozen animals can be dispatched with a single CO2 cartridge—what Goodnature bills as “more bangs for your buck”.

Flight for flightless birds. Intense management has been one of the hallmarks of the takahe recovery programme, and a number of wild birds, often tracked down with the help of bloodhounds like Yuki (top), clock impressive air miles en route to establish new populations on offshore islands and in city sanctuaries such as Zealandia, Willowbank and Orokonui. “Our new focus is on predator control,” says ranger Martin Genet (bottom). “Particularly the stoat, which is the takahe’s greatest foe.”
Flight for flightless birds. Intense management has been one of the hallmarks of the takahe recovery programme, and a number of wild birds, often tracked down with the help of bloodhounds like Yuki (top), clock impressive air miles en route to establish new populations on offshore islands and in city sanctuaries such as Zealandia, Willowbank and Orokonui. “Our new focus is on predator control,” says ranger Martin Genet (bottom). “Particularly the stoat, which is the takahe’s greatest foe.”
“Our new focus is on predator control,” says ranger Martin Genet. “Particularly the stoat, which is the takahe’s greatest foe.”
“Our new focus is on predator control,” says ranger Martin Genet. “Particularly the stoat, which is the takahe’s greatest foe.”

Improvements in GPS technology have made the monitoring of wild takahe easier, more cost-effective and less invasive. Gone are the days of nausea-inducing helicopter combat flying to flush birds out of cover so that they could be visually identified by the configuration of coloured leg bands. Now, a fixed-wing plane flies over the territory 8-10 times a year carrying a Sky Ranger GPS recorder, which logs the positions of nearly all of the 50 birds fitted with transmitters. Because the machine takes several readings per flight, rangers can ascertain if the birds are moving or not. Only a “mortality signal”, when the bird has not moved for more than 24 hours, results in a ranger’s investigation. Otherwise the birds are left undisturbed.

And yet, despite all this gadgetry, the future of the takahe population continues to hang in the balance. Even the kakapo, the most difficult of birds, with its mysterious lekking behavior when mating, and breeding as infrequent as Olympic Games, has responded with more consistency to intensive-care management, their numbers slowly but steadily increasing.

But with the takahe of Fiordland, as Phil Tisch put it, “we are just managing to hold our own”.

[Chapter Break]

On the shore of Lake Orbell, Martin Genet listens out for the takahe with his radio-telemetry receiver, dialling through the individual frequency of each bird, his hand pivoting a fold-out directional aerial above his head, finding the direction of the strongest radio signal. There are only 10 in the Takahe Valley, and the ones we saw earlier were the only pair living below the bushline. Through the receiver’s speaker the signals sound like a pulse on an ECG machine, some clear and strong, others so faint they are barely audible.

The Murchison Mountains are a harsh environment for any creature. In winter, Lake Orbell freezes over and temperatures as low as minus 18ºC have been recorded. There is often heavy snow on the steep tussock slopes above the tree line and it comes down as avalanches, white death cutting wedge-shaped swathes of destruction into the forest.

With the arrival of snow in the tussock, the takahe descend into the forest to find shelter and food. “This is what they mainly feed on in winter,” says Genet, pointing to a patch of summer-green fern Hypolepis millefolium. With the first frosts the fronds of the fern die, leaving only a network of creeping rhizomes, 2–4 cm beneath the surface of the soil, which the takahe dig up with their beaks. Studies have shown that up to 80 per cent of the birds’ winter sustenance is derived from the Hypolepis rhizomes, though it is unclear if this is sufficient to maintain them in optimal breeding conditions for the coming spring. To make things worse, Hypolepis often grows in chutes and snow-slide areas, which exposes feeding birds to the danger of avalanches.

Stoats, avalanches, unforgiving habitat and food of poor nutritional value, in addition to a natural mortality estimated at eight per cent per year—little wonder that some ecologists have been questioning whether the takahe belong in the Murchison Mountains at all.

In my 1998 article for New Zealand Geographic I wrote: “Despite almost two decades of intensive efforts, eggs and chicks shuttled by helicopters, weeks and months spent in the field by dedicated and enthusiastic DOC staff, the last summer [1997] headcount revealed just 104 birds. That’s fewer birds than during the dire days of the early 1980s when the alarm bells were first sounded.”

Fourteen years later, though the takahe are not in any immediate danger of extinction, their numbers in the Murchison Mountains are about the same—an estimated 110–120 birds, and among these only 29 known breeding pairs.

This autumn—after many ideological debates, considerations of science, budgets and past performance—begins the great takahe experiment, one of the boldest moves in the conservation history of the species.

“We want to leave the Murchison population alone for a few years, without any interference except for the continual and ever-improving predator control,” says Phil Tisch.

“We will no longer collect eggs from the birds in the wild, we will not introduce new juveniles there. We want to see if the
population is self-sustaining. The Murchison birds are the only wild population we have, so this is an important question to answer.”

As insurance, a second large population will be established. This has been attempted once before, in the Stuart Mountains, neighbouring the Murchisons to the north and across the Middle Fiord, but for still-unknown reasons it resulted in the loss of 58 captive-reared birds.

Closely-cropped tussock tillers, arranged in neat bunches like pick-up sticks, are a telltale sign of a feeding takahe. In the Murchison Mountains the birds favour the tussock above all other food sources, and head into high-alpine pastures as soon as winter snow melts above the bushline.
Closely-cropped tussock tillers, arranged in neat bunches like pick-up sticks, are a telltale sign of a feeding takahe. In the Murchison Mountains the birds favour the tussock above all other food sources, and head into high-alpine pastures as soon as winter snow melts above the bushline.

It’s been decided that the new second population will be established in a safe, controlled and easily managed environment. The hills around the Burwood Bush Rearing Unit and the nearby Red Tussock Conservation Area are the most likely candidates. The birds will live in free-range habitat pens surrounded by a predator-proof fence.

That most memorable prop of the takahe programme—the blue glove puppet with red wooden beak for feeding orphaned chicks while not habituating them to human presence—has also been decommissioned. “It was cute but extremely labour-intensive,” Tisch explained. “From now on, we’ll let the birds do their own breeding and parenting, with minimum intervention on our part. But we will foster out eggs from the birds with poor parenting records to the ones which are more dependable. Some of the 45 pairs on offshore islands often lose their first clutch because of the wild early-season weather, so this cuckoo strategy should help us prevent that.”

In these strident economic times, with many concerns vying for our attention and resources, there may be those who ask, why bother? Why maintain an evolutionary anachronism whose time has passed and which can exist only in perpetual and costly care, like a patient on a life-support system? This attitude, together with a lack of public awareness about the birds, Tisch says, is by far the biggest challenge the recovery programme is facing, beyond the logistics and finer points of predator control, safe habitats and boosting the population numbers.

In the corporate language of the modern world, where each of our iconic species now has a business sponsor to support its survival (for the past seven years the takahe programme has been co-funded by Mitre 10, which has just extended its commitment for the next three years), you could call this a lack of ‘brand awareness’.

“I’m amazed how few New Zealanders remember we still have this bird called takahe,” Tisch told me, “how fewer still feel a sense of ownership and responsibility for its fate. We restore old buildings and ships, warplanes and vintage cars because they give us a sense of history and heritage, a connection to the past and a continuum of our existence through generations. But what about our native birds? They’ve been here a lot longer. Surely, they are even more a part of our heritage. They are, together with the landscapes, what makes this country like no other.”

Perhaps part of this problem is that the takahe are so hard to access for the general public. Tisch and his team have set to fixing that, making sure that “ambassador birds” can now be readily seen in city sanctuaries such as Zealandia in Wellington, Willowbank in Christchurch, and most recently, Orokonui near Dunedin and the now well-established population on Tiritiri Matangi Island in Auckland.

Despite their iridescent plumage, takahe are well camouflaged within the patchwork of light and shadow that is their tussock habitat. “You’d think you would see them well, green-blue against yellow, especially with that big red beak of theirs,” says ranger Martin Genet, “but they can just tuck the beak away and disappear before your eyes. It’s quite a vanishing trick.” 
Despite their iridescent plumage, takahe are well camouflaged within the patchwork of light and shadow that is their tussock habitat. “You’d think you would see them well, green-blue against yellow, especially with that big red beak of theirs,” says ranger Martin Genet, “but they can just tuck the beak away and disappear before your eyes. It’s quite a vanishing trick.”

Those wanting to see takahe in the wild, and experience their own ‘Doc Orbell moment’, will have to wait. For one, it’s a logistically formidable proposition—the steep track to Lake Orbell would be a challenge for most, and, as Martin Genet warned, there’s no guarantee of even seeing the birds.

Nevertheless DOC is working to incorporate public access into the future management plan of the Takahe Special Area.

There are good things happening in conservation around the country: community initiatives, business and iwi partnerships, new and often unofficial sanctuaries created and maintained at the cost of untold volunteer hours, and the Department of Conservation—overstretched, under-funded and continually downsized—is no longer seen as the sole caretaker of our natural heritage but more as a big-picture consultant on biodiversity. It’s a diversified approach to conservation no better represented than around the takahe homeland.

The organisers of the Kepler Challenge race now run some 60 km of stoat traplines in the adjoining Kepler Mountains and have teamed up with Kids Restore New Zealand (a charity administered by the Air New Zealand Environment Trust) to enlist the help of local schools and combine predator control with hands-on education about natural values. The Wapiti Foundation does its own trapping of vermin in the Stuart Mountains, and a group of Te Anau businesses—accommodation and transport providers, tour guides, even a pizzeria owner—operates a “Buy a Box” programme where visitors to Fiordland can purchase a stoat trap for $60 apiece, which is then added to the traplines on the perimeter of the takahe area.

Shedding light on new life, ranger Glen Greaves ‘candles’ a takahe egg—the standard method to check for its fertility and date development. The new hands-off approach to takahe conservation means that these eggs will now be left to incubate naturally in the Murchison Mountains.
Shedding light on new life, ranger Glen Greaves ‘candles’ a takahe egg—the standard method to check for its fertility and date development. The new hands-off approach to takahe conservation means that these eggs will now be left to incubate naturally in the Murchison Mountains.

The perimeter is highly significant to the takahe programme, as juvenile birds travel long distances to disperse. They’ve been sighted at the entrance to the Kepler, the Worsley River near Milford Track, even in the fiords on the seaward side of the Main Divide.

“It is a big job but it can be done,” Genet told me on the shore of Lake Orbell. “New technology certainly makes effective pest control feasible and we have learnt a lot from past projects and have refined our strategies. It is now a question of priorities. Not if we can do it, but do we want to.”

In 2008, Brent Beaven, the DOC biodiversity manager for Stewart Island, conducted a study commissioned by the Rakiura Community and Environment Trust which attempted to calculate the cost of ridding our third-largest island of rats, wild cats and possums. His conclusion? It could be done, at a cost of $35–55m. A staggering amount, to be sure, but less so when compared with other public spending. In his study, Beaven cited the $34m the government put towards Team New Zealand’s 2007 America’s Cup campaign in Valencia, Spain (it has committed another $36m to the 2013 campaign in San Francisco), or the $240m it paid to upgrade Eden Park to host the Rugby World Cup. As a nation, Beaven pointed out, we spent $258m on racing and other sports gambling in a single year, $493m at casinos and $321m on Lotto tickets. But are we not also gambling, with unfavourable odds, with the future of our natural heritage?

How important are our native birds to us then? Where are our priorities? To me, following Martin Genet down the deer trail from Lake Orbell, with the vision of free and wild takahe still fresh in my memory, the choice was as clear as this perfect Fiordland day.