One of the most breathtaking animal migrations on the planet takes place every summer, when 300 million salmon make their way from the Pacific Ocean back to the place of their birth, navigating their way through Alaska’s 12,000 rivers.

They bring with them an almost unparalleled explosion of wildlife, as black bears, brown bears, Kodiak bears, wolves, bald eagles and other creatures gather for the summer feast they provide.

It’s an extraordinary spectacle and this year, for the first time, BBC cameras will be there to film it live.

Two years after the Big Blue Live captivated viewers with its real-time footage of the teeming life in the waters of California’s Monterey Bay, the BBC is taking us to America’s last frontie

Two years after the BAFTA-winning Big Blue Live captivated viewers with its real-time footage of the teeming life in the waters of California’s Monterey Bay, the BBC is taking us to America’s last frontier.

Here its returning trio of presenters – Matt Baker, Liz Bonnin and Steve Backshall – will broadcast from some of the world’s most remote locations in Wild Alaska Live which will air in three hour-long slots in the week beginning Sunday 23 July.

The heart-stopping highlight of Big Blue Live was when, against all odds, a blue whale was spotted, causing Steve Backshall to break off an interview as the footage was beamed live into our homes.

Brown bears catching salmon in the Katmai National Park, south-west Alaska

This brown bear has thrown himself into the feast as the salmon race past in Katmai

But Wild Alaska series producer Adam White promises footage to surpass even the marvels of the Pacific, whether it’s bears capturing salmon mid-air as they leap from waterfalls or humpback whales hunting in their summer feeding grounds. ‘This time we’re going to go bigger and wilder than Big Blue Live,’ he says.

Alaska provides ample opportunity for both. The largest state in the union, it has 50 million acres of wilderness – forests cut through with glaciers, mountains and raging rivers.

Roaming through it are some of the planet’s most captivating and majestic animals. And of course the salmon, the fish that underpins Alaska’s entire ecosystem. ‘It’s the most vital creature in Alaska for animals and humans,’ explains Adam.

‘It feeds the population, the animals, and it even feeds the land: bears taking salmon into the woods to eat fertilise those trees. In essence even the forests are made of salmon.’

BEWARE THE MUNCHING PORCUPINE While bears and whales will prove a big draw, there’ll be plenty of other wildlife on offer. Beavers abound in Tongass National Forest, sculpting the landscape by creating dams that the salmon must leap over on their journey upstream. In summer the beavers make the most of the thaw, rearing their young, repairing their lodges and, later on, stockpiling food. An abundant population of marmots – the largest members of the squirrel family – also resides in Tongass. More commonly associated with mountain slopes, they’ve been drawn to the coast by the warm weather, and viewers can look forward to seeing families of them frolicking by the shore. The series will take a look at how humans manage to live peacefully alongside the famously aggressive Alaskan moose, whose antlers can grow to 6ft in span. They use these to fight during the autumn mating season, then shed them in winter. One animal, meanwhile, may prove to be the Wild Alaska crew’s nemesis. ‘Porcupines love chewing rubber and can be very destructive,’ says series producer Adam White. ‘Hopefully they won’t be chewing through our camera cables.’ Advertisement

Having migrated to the sea, they return home every summer, swimming thousands of miles to the place where they were spawned in order to breed. As they travel their bodies go through an extraordinary metamorphosis.

First their skin transforms from silver grey to the deepest blood red as their internal chemistry changes to cope with the fresh water.

They then develop humps on their backs and their jaws deform grotesquely in order to fight with their rivals – the redder and more aggressive they are, the more likely it is that they’ll get to mate.

A wolf and a brown bear in Katmai National Park

‘From above the rivers look like red arteries reaching hundreds of miles into the state feeding animals and humans and forest,’ says Adam.

The transformation of the salmon is a fitting metaphor for what happens on the land: frozen for much of the year, it springs to life in this short burst of summer, showcasing a festival of wildlife.

‘Alaska in winter is a brutal place, then all of a sudden everything comes to life,’ says Steve Backshall, who will be a roaming correspondent. ‘Along with the salmon there are enormous amounts of wild flowers and other fish. It creates a focal point for a vast array of predators. You don’t see anything like this anywhere else on earth.’

Matt Baker will anchor the show from the Tongass National Forest, part of the largest temperate, or cool, rainforest region on the planet. There are islands, mountains, forest and glaciers, home to an array of wildlife from Kodiak bears, the biggest brown bears on Earth, to the bald eagles who gather in enormous flocks.

The national emblem of the USA, the bald eagle is a sea eagle and the arrival of 300 million salmon is too good to resist. ‘Their breeding cycle is geared so their chicks will get the most food they can when they need it,’ says Adam.

NOTHING CUTER THAN A BEAR CUB The Kodiak Archipelago of south-west Alaska is the only place in the world where you can see Kodiak bears – a sub-species of brown bear and the largest brown bear on the planet – smaller than the polar bear but with the largest skull of any bear. ‘Over generations, through natural selection and the fact that food’s so abundant, Kodiak bears have become the largest species of brown bear in the world,’ says Matt Baker. ‘They can reach 12ft, towering high above you – and we’re hoping to get up close and personal with them.’ They are believed to have been isolated on the archipelago since the last Ice Age 10,000 years ago. Varying in colour from beige to dark brown, they live to around 25 years and their numbers have been rising over the past decade. Alaska plays host to America’s largest population of brown bears (grizzlies are the same species but that name is only given to those inhabiting the interior; those living by the coast are simply known as brown bears), with a huge number in the Katmai National Park. Liz Bonnin will be broadcasting from here, following a two-day trip by plane, boat and on foot. Having hibernated for six months, the bears will make a long pilgrimage here to await the arrival of the salmon. It will give Liz her first chance to study these solitary predators up close – and she intends to focus on the subtleties of their interactions. ‘You might see a bear scratching on a tree and think he’s just having a good old scratch, but actually there are many reasons behind it, from leaving a scent trail to letting another bear know this is his feeding ground. Trying to unravel the layers of what those rituals means is going to be fascinating.’ And if the sea otters had the biggest ‘aaah’ factor on Big Blue Live, series producer Adam White is in no doubt what will on Wild Alaska. ‘It will definitely be the bear cubs,’ he says. ‘To think they grow into such a formidable animal, they’re just adorable. There’s nothing cuter than a bear cub.’ Advertisement

A rare treat will be a glimpse of that ultimate wilderness icon, the wolf. Working in packs, they roam the Katmai National Park chasing down moose and elk.

‘They love winter because the snow slows down the larger animals, but at this time of year it’s hard for them so they come down for the salmon,’ says Adam. With bears and wolves in the same area, there’s potential for conflict.

‘These wolves are big. One or two wolves will take on a smaller bear. But it all depends on the salmon, if there are plenty they’ll leave each other alone.’

Some footage is guaranteed: adventurer Steve has already spent weeks in Alaska, bedding down near vast walrus and tracking salmon shark, a species only found in the northern Pacific, as they gather in the estuaries to await the salmon run.

‘You can see their dorsal fins from a mile away,’ he says. ‘It’s an extraordinary sight – you expect to see it in tropical waters, not against a backdrop of snow-capped mountains.’

Humpback whales erupt out of the water as they feast on herring while seabirds hope to pick up scraps

The national emblem of the USA, the bald eagle is a sea eagle and the arrival of 300 million salmon is too good to resist

In the Pacific Steve hopes to show us humpback whales who have travelled thousands of miles to their summer feeding grounds.

They hunt in a way seen only here: working in teams, they blow rings of bubbles, netting fish and forcing them to the surface.

‘You can watch these 40-tonne animals erupt out of the water, herring flowing everywhere, seabirds trying to feed on them. It blows your mind and I’m 90 per cent sure we’ll see it live,’ says Steve.

THE FILM CREW'S SECRET WEAPON Fifty million acres of wilderness present big problems for film-makers. Alaska’s inaccessibility means that the Wild Alaska Live crew are, as series producer Adam White puts it, ‘pushing the limit of what is possible with outside broadcasting’. His scouting missions unearthed a ‘plethora’ of stunning locations teeming with wildlife – but what they didn’t have was a working satellite signal. ‘Because Alaska is so high up on the planet quite a lot of satellites are very low in the sky, which isn’t helpful,’ he says. ‘I went to some amazing places, then I’d bring the engineer in and he would say we couldn’t get a signal.’ That wasn’t an issue in the ‘hub’ location – the Tongass National Forest near Alaska’s capital Juneau, from where Matt Baker will be anchoring the coverage – but even creating an operations centre there presented challenges. ‘You actually can’t drive to Juneau, you can only fly or get a boat there – it has about 50 miles of roads but they don’t go anywhere,’ explains Adam. ‘We had to put our equipment trucks on a barge and send them up from Washington state.’ The crew doesn’t use drones to film, but the secret weapon is a helicopter with a ‘super gyro stabiliser’ beneath, allowing the crew to use a telephoto lens to capture stunning aerial footage of what’s unfolding below. ‘The stabiliser means the camera remains steady even if the helicopter is moving. They used them on Planet Earth II to magnificent effect,’ explains Adam. ‘They allow you to film from a long way away and get a really intimate shot so we’re incredibly excited about the footage we can get of the whales.’ The Katmai National Park, where Liz Bonnin will be monitoring the brown bears, is one of the remotest parts of Alaska, Even at its most accessible point it’s 300 miles from the nearest road. ‘Everything we need has to be brought in on a three-wheeled biplane that can only be landed at low tide. Then we have to carry the equipment to camp through a forest full of bears and wolves,’ says Adam. Advertisement

It’s why he’d rather spend time filming in Alaska in summer than anywhere else. ‘Even more than the great wilderness migration on the African plain or the Great Barrier Reef, because the spectacles are more dramatic and we stand more chance of seeing things that are going to astonish people.’

It’s a sentiment echoed by Matt Baker, who says the whole aim of the show is to reveal these multiple slices of nature in all their glory.

‘The whole point is to get families in Britain sitting down in front of their TVs and seeing what’s happening on the other side of the world at exactly the same time as they’re watching it,’ he says.

‘That’s what I loved about Big Blue Live. It became appointment viewing.’ Series producer Adam White hopes it will make the viewer reflect on their place in the world.

‘Most of the time in the UK you have little to be afraid of, you feel you’re on top of the food chain. In Alaska that’s not necessarily the case and it’s a timely reminder that we are one small part of this whole planet. It’s a wonderful, humbling experience.’

Wild Alaska Live, Sun 23 July at 7pm, Wed 26 July at 8pm and Sun 30 July at 7pm on BBC1. You can also see exclusive footage on Wild UK, Mon 24-Fri 28 July at 9.15am on BBC1. Matt Baker is at Countryfile Live, 3-6 August, Blenheim Palace, countryfilelive.com.