NZ ` the largest landmass above sea level of a vast continent that broke away from Gondwanaland. 23 million years after the landscape emerged form the ocean depths, it's still as diverse as it is unique. Remote corners of this world have seldom been seen. Isolated and rugged, unique plants and creatures have evolved that are found nowhere else on earth. Since the arrival of human life, this wilderness and many species have been under threat ` some lost forever. But today, almost a third of this dynamic country has been protected. 14 national parks have been established to preserve this diverse landscape and the multitude of life that live here. Gus Roxburgh is an environmental specialist and adventure guide who's heading out to explore the country's wilderness and discover the often unseen backcountry world of these national parks. 125 years after the first national park was created, he wants to capture a sense of what these ever-evolving conservation parks have become through the people who work, play and preserve the wilderness that is our national parks. And I think you'll find it's quite possibly the best backyard in the world. Captions were made possible with funding from NZ On Air. Copyright TVNZ Access Services 2013 The central North Island of NZ ` a vast desert-like landscape known as the central volcanic plateau. Rising from this unique geology is the commanding presence of three volcanic mountains. To Maori, they're ancient ancestors ` Ruapehu, Ngauruhoe and Tongariro. In the foothills of these volcanic bastions lie the upper reaches of the spectacular Whanganui River. It carves a path to the Tasman Sea through the largest tract of lowland forest in the North Island. These dynamic landscapes and the wildlife that call them home have been protected in two distinct conservation parks. Tongariro was the first conservation park in NZ and the fourth in the world. 20km to the west is the Whanganui National Park, bisected by the Whanganui River, the longest navigable waterway in NZ. Neighbours by location, these two conservation sanctuaries are in stark contrast to one another ` Whanganui, formed by the uplift of the seafloor 30 million years ago; Tongariro, by a ferocious geological force just below the earth's surface. This is also a park whose rich history and evolution is as volatile as the mountains it preserves. That was the mana of Tuwharetoa expressing itself to the world. Every part of me bubbled and fizzed. I loved it. It's still alive. Te Ngaehe Wanikau's genealogy descends from both Te Wharerangi, a great regional chief, and from the great tribal chief Horonuku Te Heuheu. Horonuku was pivotal in protecting what he saw as living, breathing mountain ancestors. Each time I look at the mountains, I look at a tupuna, an ancestor. I see a repository of all our stories. This is our cathedral. This is the place where we celebrate life, where we mourn death. Without Tongariro, we cease to exist as a people, we have no identity. After wrestling with the Crown over the ownership and use of Tongariro, it contentiously evolved to become a protected park. Horonuku saw a place that would preserve things for all eternity. It wouldn't become real estate. And in his so-called gifting, he said, in Maori, 'My people's mana remains on these mountains. 'From the place where vegetation ceases to grow to the sky, 'I will share it with the nation, and I will share it with the world.' Tuwharetoa believe the original 26.5km2 of park was not gifted by Horunuku but rather coerced from him by the crown. This original land confiscation encompassed the peaks of Tongariro, Ngauruhoe, and the northern peaks of Ruapehu. To expand the park, the government controversially confiscated more land from the tribes Ngati Rangi, Ngati Uenuku and Tuwharetoa. This land is still part of the 800km2 of the park today. We want to share the mountains. It's never about us trying to keep people out, but it's about us not being erased from the landscape. The fiery hearts of these towering Maori ancestors are steeped in mythology. The Tuwharetoa tribe believe that when high priest Ngatoroirangi was frozen by a bitter southerly and close to death, he called to his sisters for fire to bring warmth to the mountains. The Whanganui tribes believe Paerangi, the god of the Milky Way, descended from the heavens to draw forth the volcanic activity. Whatever the mythical history, these mountains have been created by powerful forces of nature. Beneath these brooding beasts, the earth is very much alive. Only 16km beneath the surface, two giant tectonic plates grind and clash against one another. Further below, molten rock meets with water and volatile gases, both desperate to escape and burst through the earth's shallow crust. Small cracks serve as vents to release lava and gas. 250,000 years of ash and lava have created mountains with central vents, forming summit craters. This landscape is a ticking geological time bomb. ERUPTION ROARS But the irony is that almost one million people a year are drawn to the park, despite the ever-present threat of the powerful forces that lie beneath. Just down below me there is the Tongariro Alpine Crossing. It's one of NZ's great walks, and it's the most popular day walk in the country. It goes through one of the most active volcanic zones in the whole world. The 20km crossing traverses over the surreal moon-like landscape of Mt Tongariro, including the spectacular Emerald Lakes. Their brilliant green colour is caused by minerals leeched from the surrounding rocks. But behind the scenes around here, there's a ton of work being done to monitor these volcanoes and hopefully predict when things are getting a little bit too exciting. Mt Ruapehu has erupted over 60 times since 1945, and Tongariro exploded back into life after being dormant for over 100 years. With a growing number of visitors on the mountains, risk management is crucial. There's 75,000 people a year, increasing at 10% a year, going right past this area. Many people are going right close to the craters, so we need to have systems in place and manage that risk. Harry Keys is a Department of Conservation analyst, one of a number of dedicated specialists keeping an eye on the volcanoes. This crater has been reamed out by the eruption on the 6th of August this year and deepened and sharpened the sides. You can see some cracks down there, where the ground's collapsing in, and you can hear the roar of gas coming out. These highly-toxic acidic gases are pulsing from the vents at up to 250 degrees Celsius. It's really toxic, that gas. If you haven't got a gas mask, it's crazy coming to a place like this. If you haven't got a gas mask, it's crazy coming to a place like this. Wow. You can feel that warmth now, can't you? Yeah, pretty powerful. This is some of the most powerful parts of volcanoes. OMINOUS MUSIC God, look at the colour of that, though. It's like a full spectrum of yellow. So is that all sulphur, or what is it? The yellow stuff is sulphur. The orange stuff has got arsenic in it. On one hand, these gases are deadly. On the other, they're a vital sign to the volatility of the volcano. Drops in the levels of gases such as sulphur dioxide could indicate a blockage, leading to a rise in pressure and a potential eruption. We can't exaggerate that we know exactly what is going on. These volcanoes are unpredictable. So there is a sort of uncertainty that we gotta manage around. The volcanoes are the bosses. Some people think we can conquer them, but we can't. All we can do is learn to live with them, and that's what we are trying to do ` help people live with them. Keeping tabs on the eruption status of the mountains is an ongoing process that involves constantly gathering data and evaluating the risk. To assess the hazards to those in the park, the Department of Conservation have scientists monitoring the inner workings of the volcanoes. These are algaes and bacteria that are growing in the water, and you will see the different colours. If we just look at the temperature ` in the centre there is around 40 degrees. And it's pretty warm. And it's pretty warm. It comes out to the green and it drops down into the 30s. Right. So it's very colour dependent. So what we're looking for here is the hottest place. Where the hottest water's coming from, we'll collect a sample from there. Brad Scott is another scientist who frequently travels to the hot zone, investigating the vital signs of a possible eruption. The fluids from the geothermal system are coming from inside the volcano and we can actually look back into it by collecting the fluids. The chemistry is part of the story. We have other technologies ` a network of seismographs around the volcano, and that allows us to see if volcanic tremors are occurring, if gas is moving through the volcano. We put all those bits of information together ` the chemistry, gases, earthquakes, ground deformation, and sort of build up a picture of what the volcano is up to. Different parts of the volcano can behave differently. if you saw multiple features on Tongariro changing at the same time, that would be indicative of something quite large trying to happen. What's going on at Ruapehu? Cos that's got an alert at the moment. There's increased unrest going on at Mt Ruapehu at the moment. Um, the crater lake temperature is staying cool ` around 20 degree Celsius. The temperature underneath the crater lake is increasing, but it's not coming through the crater lake. So something's blocking it? So something's blocking it? It's basically blocked. The crater lake on Mount Ruapehu has the potential to send a violent lahar crashing down the mountainside at any time, as it tragically did, Christmas Eve 1953. That night, a lahar of unstable ice, rubble and ash collapsed around the crater lake. Sludge and rock raced down the mountain at speeds of up to 100kmph, flooding the Whangaehu River - destroying the Tangiwai rail bridge 35km away. Minutes after a bridge support gave way, a crowded express train plunged into the river, and 151 lives were lost. 1 The crater lake on Mt Ruapehu has been constantly warmed by the volcanic gases steaming up from the magma chamber below. In the 50s and 60s, it was often used by swimmers until the acidity levels climbed to such a degree it became toxic, and scientists were concerned about the possibility of an eruption. 60 years on, NZ's largest ski area is just 500m from the unpredictable crater lake ` a highly volatile environment that could take lives in a matter of seconds. There's now a complex system of sensors to warn of an impending lahar from the crater lake. If all things, um, point towards an eruption happening, then it sets off the alarms up here. How much warning do you get when one of these things comes down? How much warning do you get when one of these things comes down? Um, about 90 seconds from eruption time to, uh, the lahar entering the` the top part of the ski area. Part of Andy Hoyle's job as a ski patroller on Mount Ruapehu is to prepare people for the possibility of an eruption. We want people out of the valleys, get to the ridge. Wherever you are in the ski area, you can get to a ridge top within 20 seconds, 30 seconds easy. It's all about getting to a high spot? Yup, hear the sirens, see an eruption, move to the ridge and wait for further instructions. All we know is that we love it here; it's part of the adventure. You can get out and ski amazing terrain that's just unmatched, I think, in the world. Working on the side of an active volcano is just another part of the job description in Tongariro National Park, but it's not just the volcanoes that make this a challenging place to work. Standing alone in the middle of the North island, these mountains bear the brunt of the westerly weather blown in from the Tasman Sea. The moisture-laden air is super cooled by the conditions. It freezes in a matter of seconds, wrapping its icy grip to any exposed surface that's at or below freezing temperature. The ski field on Mt Ruapehu battles against some of the worst rime icing conditions in the world. Ski lifts are frozen shut until the towers are cleared, but if the ice builds up too quickly, the lifts can collapse under the weight. Would this be pretty bad icing for you guys? It's pretty mild stuff, to be honest. So you can get, like, a few centimetres forming up in just a couple of hours? Yeah. On a, uh, sort of, normal de-icing day, you and I, right now, would be, uh, covered in about a good inch of ice on our jackets, so,.. and that's a half an hour period. We just need to clear a bit of this ice off this ladder there so we got a good free climb up. Get to the top there and, uh, I'll let you loose. 'The wind's blowing around 70km/h, but for Johnny Tewano and his team, this counts as an easy day.' What's the strongest winds you guys can operate in? I mean, must be pretty edgy up on top of some of the towers. It's to a point where it's unsafe and we either can't stand up there any more, or, uh, conditions blow us over. I think with the old wind reading we've been up here 140 K, 150 K. That's` That's nearly 100mph. Yeah. That's one tower, out of about 10 on this lift, and there's at least 10 lifts to clear, all before 9 o'clock. In these extreme conditions, any kind of maintenance takes time. But there's one thing that doesn't. Weather patterns here can change dramatically in a couple of hours and, in some cases, minutes. Still, for some hardy souls, nothing will get in the way of making the most of the extreme conditions. From the roof of this extreme and volatile landscape, to the desert-like lowland, forces of nature have had a profound effect on this volcanic plateau. Around 1800 years ago, NZ experienced the most massive volcanic eruption to occur in modern history. The explosion created nearby Lake Taupo and sent a fiery cloud of hot rocks and dust that flowed at speeds of up to 700km/h. The ash cloud turned the sky red as far away as Italy. Enormous quantities of pumice spread over 21,000km2. In one cataclysmic event, forests were levelled, incinerating and burying vegetation. But life has a way of finding its feet. Pollen profiles reveal that within 200 years of the eruption, forests rose from the ash-laden landscape. Many became treasured by early Maori ` not only providing shelter, but also supplying a storehouse of amazing medicinal remedies. And was there any use for this matai tree? Yeah, it's medicinal. You could take the sap from this tree and the sap from a rimu tree, you blend them together, and let's say you cut your finger, you could put some of that on to your finger and it will heal it up quite quickly. You're still using that now? You're still using that now? Yeah, absolutely. How old do you reckon this tree would be? Oh, this one's about 900 years old to 1000 years old. Oh, this one's about 900 years old to 1000 years old. 1000 years old, eh? That's amazing. While no one can remove vegetation from this protected forest, Ngahuia Rameka and her family still make use of the ancestral medicinal knowledge that's been passed down. So this plant here, this is called, um, in English it's called hen and chicken fern. This part here we call pikopiko. It's nicknamed bush asparagus, so you cook it the same way as asparagus. But we can't pick them, because we're in a Department of Conservation forest, so just like all the good cooking shows, here's one I prepared earlier. OK, so that's pikopiko, you can eat the whole thing. You can eat it raw? You can eat it raw? Yup. It's pretty good, isn't it? Kind of peppery. There's a couple of good restaurants in Auckland that use them as garnish on top of their dishes. Mm-hm. Hey, here's another one. This is, um, piotako. Say you've got a hole in your tooth and it hurts a lot when you eat sweets or lollies, you could take part of that vine and you chew on it, and then it will numb all that area, so you can't feel that pain so badly. Since the devastation of the eruption 1800 years ago, forests in the region continue to fight back, regenerating around the skirt of the mountains. On the south-western side of the mountains of Tongariro National Park, the neighbouring forest of the Whanganui National Park was sheltered from the Taupo eruption, and the immense Whanganui River flowed through the forests and was the lifeblood of the region as it traversed for almost 300km. This massive waterway is still the longest navigable river in the country. A watercourse where travellers can be cut off from civilisation for days on end. Look at those big, brown eyes. This is the time he won 'Baby of the Month' competition for the local Courier newspaper. 'Course, we weren't in very much doubt about it, cos he's so photogenic, eh? (CHUCKLES) I used to dread these afternoons. Now I positively cherish them. Play music. (JAUNTY CLASSICAL MUSIC PLAYS) Buckle up, Margaret. This is the future of bragging. # Oh, oh. Oh, oh. Oh. # 1 Beginning life on the north-west flank of Mount Tongariro, the Whanganui River winds its way to the Tasman Sea, fed by surrounding tributaries. The waterway traverses through vast rainforests and deep gorges. For over 25 years, this park has protected one of the largest expanses of lowland forest remaining in the North island ` an ecosystem of podocarp-hardwood trees; a habitat that has been decimated from much of NZ. It provides a sanctuary for some of NZ's unique wildlife. This rugged and inaccessible landscape has no throughroads. Like the path of the river, an epic cycle journey also begins in the mountains, traversing through the Whanganui National Park to the Tasman Sea. Descending from the mountain slopes, it passes over the Hapuawhenua Viaduct ` a decommissioned rail bridge towering 45m over the gorge below. It's a gorgeous place for a bike ride and a pretty amazing piece of construction when you think that they made this over 100 years ago. But the guys making this didn't have an easy time with the weather. In a nine-week stretch, there were only five days when it wasn't pouring with rain. Completed in 1908, the viaduct was part of the main trunk line from Auckland to Wellington, until it was replaced in 1987. But today, the only way into this part of the park is by foot or by a bold new experiment to allow mountain bikers to explore the park. George Taylor from the Department of Conservation was instrumental in the creation of the Mountain to Sea Cycleway. What's going on here, George? Well this is a remnant from the old days, really. This is the Mangapurua, where the government tried to open this area up for farming to World War One soldiers coming back from the war. They allocated them land and told them to go in and give it a go, break it in. No chainsaws back then, was there? No chainsaws back then, was there? No, just an axe. Just a man and an axe, and that's pretty much it. Over 30 families made a valiant attempt to settle in the area, and for a few years, the valley communities prospered, supplied by a government-funded road. But the rugged terrain, poor soils and economic hardship took their toll, and the families started slowly leaving the valley. The bridge to no where. This is a remnant of what they tried to achieve back in the day, you know. By the time they put this up, um, people were already starting to abandon the valley. There's only ever been one vehicle to actually drive down and go across this bridge. It was a car, and it turned around at the end and went back out. The onset of World War Two saw the government stop funding maintenance of the road. After a couple of major flooding events in the 1940s, the last of the settlers left the Mangapurua Valley, and nature began to reclaim the land. The old road eventually became a track used only by hunters and trampers until it was developed as part of the cycle route. The Mountain to Sea Cycleway is divided in two by the imposing Whanganui River. With a length of 290km, it's the country's third-longest river. Before the arrival of European settlers, the area around the Whanganui River was one of the most populated in the country. The river provided trade and communication between the many settlements. Traps for eel lined the riverbanks. Once a busy thoroughfare for freight and passengers, the Whanganui River's traffic is now nearly all recreational. Jet boats provide a shuttle service from the Mangapurua landing to Pipiriki, where the cycleway trail continues. Joe, how long you been on the river? Um, been involved with it all my life ` from my earliest memory, sort of, 4 years old, yeah. The whole river trench hasn't changed at all. It's basically what it was like hundreds of years ago. Joe Adam is one of a long line of boat operators that have spent their lives transporting people and supplies on this mighty river. Before the central plateau was opened up, this was basically used as a main highway, and steamers were coming up from Wanganui, wakas were coming up and down. The river became a tourist destination, sort of, early 1900s when they started bringing the steamers up here. BELL DINGS Advertised as The Rhine of NZ, the rugged beauty of the Whanganui attracted thousands of visitors each year. Even with a deepened river channel, boats had to be winched up the more difficult of the Whanganui River's 200 rapids. As soon as they opened up the main trunk railway line in the early 30s, basically everything stopped, yeah, or slowed right down. The tourists may have changed over time, but the river hasn't. It still has the potential to rise dramatically by a couple of metres overnight. It's not a dangerous river; you've just got to respect it. When it floods, it floods very quickly. It's a beautiful river, you know. It's an awesome river, as long as you respect it. They ever gonna get you away from here? They ever gonna get you away from here? Nope, not even in a box, mate. As the river carves its path through the heart of the Whanganui National Park, the tempestuous mountains of Tongariro National Park, 60km away, seem distant. But in the 1970s, there was a reminder of the umbilical connection between these neighbouring parks. An eruption from Mt Ruapehu flushed toxic water into the Whanganui River, decimating fish life downstream. The vast expense of rainforest in the Whanganui National park is home to a large number of native plants, insects and birdlife. It's also home to unique species ` NZ's only native land mammals, the long and short tailed bats. Slightly larger than the human thumb, the short-tailed bat has no close relations anywhere else on the planet. While other bats hunt in the air, the short-tailed bat can wrap its wings around its legs to crawl like a mouse, foraging on the forest floor. Before introduced predators arrived in NZ, the bats were safe to forage all night. They're now found at fewer than 20 locations, including the Whanganui National Park. When Polynesian rats, possum and cats were introduced, almost half our native birds and three species of lizard and frog were wiped out. And there's one introduced species, not commonly viewed as a predator. Wild pigs are scavengers and foragers that can ravage native plants, insects, and the eggs and chicks of ground-nesting birds. But the introduction of the pig by Europeans in this region also provided a major new food source and soon became the main supply of protein for Maori in the Whanganui. And this is all about getting food for the marae, huh? Food for the marae. The old, um, settlers when they came in it was their staple diet, and the Maori adapted and adopted. Unlike early Maori, Baldy Hitana's approach is high tech. Each dog is fitted with a GPS satellite tracking device. They're released into the hill country, and the hunt is on. Have they gone over the top? Patch is at 536 and so is Jaffa, so they're all in the same place. And that means one thing ` the dogs have cornered a pig and the GPS technology pinpoints the location, saving time and a whole lot of effort traipsing over this rugged countryside. These wild pigs are often smaller and stronger than domesticated pigs, and capable of considerable damage in a short amount of time. Today, pig hunters in the Whanganui National Park have helped the Department of Conservation drastically reduce the population of wild pigs, while also providing food for the only marae that exists in a national park. Tieke Kainga marae has always been a unique settlement and was once a major trading centre on the Whanganui River. This was a chief marae where everyone, all the hapus up and down the river, came to have a discussion. If there was a concern, then they would sit here for a day or two until everything was solved. Boy Cribb and his iwi have continued the tradition of keeping this marae open for all their wider whanau, and this is also the only marae in a national park that's open to travellers from around the world. And the uniqueness of it is the relationship between the Department of Conservation and, um, Te Whanau o Tieke. So people can actually come and stay here in a marae in the middle of the park? Yes. Now we have, uh, cyclists coming. We have still rowers coming through. As long as they follow our protocol to the marae and work to DOC's requirement, we have no problem. Sitting here at Tieke, it's hard not to think about the future of our parks. It hasn't been an easy road, but DOC and the local iwi have worked together and built a relationship, and today you have got a place with the marae right behind me and the DOC hut beside it, and it's a pretty amazing example of co-management in a park. And the fact that visitors could potentially be helping keep wild pig numbers down, which in turn increases native species populations, is a huge incentive for promoting schemes like this in our parks. The Whanganui National Park has a distinct landscape of river valley systems with steep slopes, razor-sharp ridges and an almost complete cover of native lowland forest. The inaccessibility and the size of the park, is a double-edged sword. It provides a unique sanctuary for our wildlife, including one of NZ's largest population of kiwi. It also means monitoring them and their predators is a massive undertaking. Enemy number one is the stoat, capable of swimming for up to 1km and travelling over 30km per day. Stoats can live in any habitat that has prey, from beaches to high altitudes and any variety of forest. A pest-control programme using the controversial poison 1080 has been implemented in this park to help halt the stoat's impact and increase kiwi numbers. Monitoring the kiwi population in 160,000ha of rugged terrain is a challenge that requires an innovative and high-tech solution. So, basically it's just a microphone down the bottom there. Every 15 minutes it records what it has heard, so it cuts down on battery use. So I can get 130 hours of listening out of this. Daniel Hurley and his team use digital audio recorders to pick up the nocturnal calls of the kiwi, allowing them to calculate the size of the population. So, how sensitive is the mic on this thing? Very sensitive. You will pick up the weta clicking their legs. Very sensitive. You will pick up the weta clicking their legs. Wow. 'The practice of setting and retrieving audio recorders has been in place for three years now 'and is a critical technology in measuring how this kiwi population is doing.' So, how long's this one been out here for? So, how long's this one been out here for? A bit over three weeks, yeah. But it will be just quite interesting to see if there is a new kiwi around this area. We'll go chuck this in the computer and show you how it works. That there is the` the hum of an aeroplane going over head. OK. > You obviously get to know what different sounds look like, huh? You obviously get to know what different sounds look like, huh? You do. You get quite fast at it. About five hours' worth of listening I'll get through in 15 to 20 minutes. Here we go. Wow, look at that. Yeah, no. That's, um, amazing, actually. You think that's kiwi? You think that's kiwi? KIWI CALL That's a real guttural sound. That's the grumpy female. Making a call, and they should be right here. There should be a... Making a call, and they should be right here. There should be a... HIGH-PITCHED KIWI CALL Male kick in there. Yeah, so it's a really strong duet, which is cool. Would there be a way to actually tell different kiwis? There's a downward sound on the end of the male call, and it looks like the tail end is quite unique. They can possibly pick out different male kiwi. Over time, Daniel's been able to determine in more detail what the birds have been up to, from snoozing and snacking to courting. I'd say it looks like we've picked up on an intimate moment out there in the bush between two kiwis. I've talked to people who spend time in the bush, and they reckon they are more social than we think. Kiwi calls have been detected at 60 separate sights in the 160,000ha forest. The frequency of recorded calls has been increasing over the years since monitoring began, clear signs that the kiwi population could well be benefiting from the pest-control programme. 1 Beneath the dense vegetation, the land is primarily soft sandstone and mudstone uplifted from the seabed just a million years ago. As the river carves its path, it exposes the massive mudstone layers, and provides the sensation of being cradled deep in the heart of a magnificent ancient rainforest. This is unbelievable in here, Sheree. It's amazing, isn't it? It's amazing, isn't it? It's really cool. A lot of people just kinda forget that there's these amazing places in NZ that are so remote. 'Canoeing down the river is certainly the best way to appreciate what makes this landscape so unique. 'Sheree Brown has been guiding people down the river for the last four years.' It would be impossible getting around here, other than on the river. You'd never be able to climb those banks. The Maori, when they used to have their villages on the tops there, they'd use, um, vine rope ladders. Must be nearly 100m up some of these big banks. Must be nearly 100m up some of these big banks. Yup. There's a great story, actually, of how one of the tribes in this area used to deal with their enemies. The chief ` he'd send his beautiful daughter out to the mouth of the river, and warriors would come down and they'd see the beautiful girl and they'd, uh, follow her into the` you know, the narrow gorge here, and they'd drop down the rope ladders, and then she'd scramble back up. And, uh, the tribe from above would just drop huge boulders down, and that's how they... Serious? Serious? ...that's how they got them, yeah. Serious? ...that's how they got them, yeah. It's kind of a perfect trap in here. There are countless streams and rivers scattered throughout this park, with over 200 white water rapids on the Whanganui River alone. These clean, fast flowing waters have evolved a unique water fowl ` an endangered species found nowhere else in the world. There are fewer than 3000 whio, or blue duck, remaining in NZ. This population is fragmented and isolated. They're renowned for having low reproductive success and are increasingly dominated by males. The whio gets its name from the distinct call made by the male bird. (WHISTLES) I've been doing this job for the last 10 years, and probably the first five or six years, I practically lived on the river. Rufus Bristol is an expert in monitoring a bird more endangered than the kiwi. This is a mixture between an inner tube and a kayak. Uh, yeah, and it just happens to be the perfect vehicle for us. In these fast moving waters, the lightweight rubber tubes are tough and able to slide over the rocky rapids in search of whio. Hey, there's a bird pair with chicks. 'They're amazing little white water specialists that stay in the same stretch of water for years at a time 'and aggressively defend their patch.' He's keeping a pretty close eye on me. He's keeping close. You see how he moves? Watch his head and pay particular attention to his head and his eyes, cos whatever his eyes are looking at, that's what he's thinking about. There they go, just heading back up the river. Rufus is saying this is the end of their territory. Got about a kilometre of this river. That's where they call home. And thanks to the reduction in stoat numbers, this 30km stretch of protected water now has around 40 breeding pair of whio. The biggest threat is always the stoats. We got a trapping regime here. I don't think we're ever gonna get rid of them, not in the immediate future, but we can contain the numbers. She's got one chick with her. That's all she had yesterday. Probably that's all she's got left out of the six. Unlike some endangered bird species, blue ducks can't simply be transferred to off-shore islands to protect them. They rely on large tracts of quality, fast-flowing river habitat that's unavailable on islands. The survival of this species will be through the protection of secure populations like this one here. Each of our parks has its own thing going on, its own landscape and its own special feeling, but I think the thing for me about Tongariro and Whanganui National Parks is that up in Tongariro, the volcanoes are definitely still in charge, and down here, this terrain and the bush has pretty much beaten off any attempt at settling here. And I guess, for me, that is what national parks are all about. It's about having a place where nature dominates. The Whanganui River continues to weave and contour the rocky ravines, shaping an epic river journey like few in the world. It's in this unique wilderness that NZ's endangered species have a real chance to fight back as they shelter in the country's largest natural sanctuary. Whanganui National Park is an ecosystem like no other with pockets still undiscovered. Its neighbouring park, in the centre of the volcanic plateau, has an indomitable history. These are untamed landscapes, unable to be subdued, a restless underworld, unpredictable... BOOM! ...and explosive. The Tongariro National Park is one of the most unique and volatile playgrounds in the country. Captions by Brittany Stewart. Edited by Desney Shaw. www.tvnz.co.nz/access-services Captions were made possible with funding from NZ On Air. Copyright TVNZ Access Services 2013