Original subtitles

In the far north of Europe is a land steeped in myth.

The realm of Thor...

..and Odin.

From Norway's frozen wilderness...

..deep into magical Swedish forests.

Across Denmark's windswept shores...

..to explosive Icelandic volcanoes.

Scandinavia's breathtaking landscapes...

..have shaped its people...

..and its wildlife.

Where the land meets the sea...

..there are great gatherings of life.

But also many challenges.

Only the tough and the resourceful...

..can carve out a life...

..on this wild, unpredictable frontier.

As Scandinavia emerged from the last Ice Age,

a spectacular coastline was revealed...

..reaching out into the turbulent Arctic and Atlantic oceans.

But our journey begins in the more sheltered Baltic Sea.

Off the coast of Sweden,

30,000 islands stretch far out into these icy waters.

And at the outer fringes,

this skerry has some new arrivals.

Over 1,000 grey seal pups.

They may look laid back,

but they're all in a perilous race against time.

PUP SNORTS

Just 18 days after being born,

they will be abandoned by their mothers.

Before that moment, to have the best chance of survival,

the pups need to quadruple their body weight.

Glugging three litres of super-rich milk a day builds up blubber -

a vital energy store and protective insulation.

THUNDERCLAP

On this exposed coast,

fortunes can change in an instant.

As the swell builds ahead of a late spring storm,

pups that linger too close to the edge

are vulnerable to rogue waves.

The storm takes a terrible toll.

Pups washed into the sea quickly succumb to the cold.

In the Baltic,

up to half of all pups don't make it through their first year.

The squall has left the shoreline treacherously icy.

But with so few days together,

crucial life lessons can't be put off.

This pup needs to improve his swimming skills.

And Mum needs to be on her guard.

BULL GROWLS

Aggressive bull seals skulk around the shoreline,

on the lookout for a mate.

The water is dangerously cold for the pup

as his fur offers little insulation.

So this must be a quick dip.

She stays close.

BULL SNARLS

But then a sneaky male intrudes.

Instinct drives the pup towards shore.

But the way is blocked by another male.

Forced back into the surf,

the pup is swept away.

Amongst the slosh, a sign of life.

Washed into a cove,

this pup has been lucky.

PUP WHINES

But his ordeal is far from over.

Spurred on by his mother's calls,

he slowly claws his way over the ice to safety.

Reunited,

it's time for a warming feed.

These devoted mothers have not eaten since giving birth,

sacrificing a third of their body weight to give their pups

the best start in life.

Now starving,

they must abandon their pups and return to the sea to feed.

One last look,

and she's gone.

PUP WHINES

Too young to follow,

the deserted pups head inland.

Here, they stay for several weeks,

living entirely off their blubber reserves.

They shed their white fur and grow a shorter waterproof coat.

An outward sign of miraculous changes

happening to their bodies

as they transform into seagoing youngsters.

Finally, they're ready to take the plunge

and leave these ancient granite islands behind.

Further south, rocky shores give way to ever-shifting sands.

This stretch of Denmark's coast

is part of the largest tidal flats on the planet.

Over 500 square miles of silt and mud

reshaped and revealed

with the ebb and flow of each tide.

It's a vital refuelling stop for millions of birds

on their annual migration to the Arctic to breed.

Mingling with the locals,

these travellers are drawn here by a smorgasbord

of delicacies buried in the mud.

And these worms, clams and crustaceans

are best gathered as the flats are exposed by the falling tide.

Each bird has its own unique way to harvest the hidden feast.

Avocets sweep the silt,

snagging worms and shrimps.

With their long, straight bills,

godwits probe the deeper mud.

Whilst red knot patrol the tide lines,

hunting for clams to swallow whole.

The feasting continues until the tide turns.

Then, as the water rises...

..food is once again submerged,

beyond the reach of the longest beaks.

Buffet over, they take to the air in their thousands...

..finding safety in these shape-shifting crowds.

For a few weeks,

they are slaves to the rhythm of the tides...

..before resuming their journeys.

Heading north, many will pass over Skagen Point

at the very tip of Denmark.

Here, water funnelling out of the Baltic

meets the tidal surges of the North Sea.

Together, they give rise to a new force,

the Norwegian Current,

which powers its way towards Scandinavia's

most spectacular coast.

The Norwegian fjords.

Long, twisting canyons

formed when glacier-carved valleys flooded with sea water

at the end of the last Ice Age.

While, according to legend,

these rocks are the bones of Ymir,

a giant slain by the Norse god Odin.

Some fjords reach over 100 miles inland,

with sheer walls rising over 1,000 metres.

This rugged coastline nurtured the Viking traditions

of seafaring and exploration.

Someone continuing that same spirit of adventure

is Hege Ringard.

- I'm mentally prepared the whole hike.

It's one thing I definitely like, being on mountains,

is that they're massive

and I'm this little...lady, like, walking around there.

And you're vulnerable.

- Many Norwegians embrace the idea of friluftsliv,

a passion for the outdoors.

But Hege takes this tradition to the extreme.

- Walking to the edge,

I focus on my breathing.

I am very much in the moment.

- She needs to be totally in tune with the elements.

Her life depends on correctly reading the wind

and the weather.

- You can never really trust the weather forecast,

but you can trust what you see right in front of you.

What you can see right away is the waterfalls.

How are they falling? Straight down?

Or are they moving a lot?

And that could be a good hint

that maybe it's a good day to go base jumping.

I clap.

My body and my brain is, like, working together,

and the clap is like a little wake-up thing.

And then I jump.

Slowly, the wings will fill up with air.

It's like this soft, sweet emotion.

It doesn't feel that fast, actually.

It's like an enjoy-the-view kind of thing.

And get off the mountain.

- Norway has more fjords than anywhere else on the planet.

Their twists and turns add over 16,000 miles

to Scandinavia's coastline.

So Hege has endless possibilities to satisfy her obsession.

- It's such a cool way to go up on the mountain

and then fly off of it.

It feels like a privilege.

Thinking about just being there in the moment.

I'm not thinking about what's for dinner later.

I'm just enjoying it.

Being out there just makes me feel good.

So that's why I keep going back again and again.

- Where the fjords spill out towards the open sea...

..tides churn the shallow water into a plankton-rich soup.

A hunting ground of some voracious predators.

Lion's mane jellyfish.

With a dome up to a metre across,

these giants trail hundreds of delicate tentacles

to trap plankton and fish.

Up to 30 metres long,

each tentacle is packed with stinging cells

that fire when touched,

paralysing their victims.

But some have turned these deadly tripwires into a safety net.

Whiting fry seem immune to the jellyfish stings,

which gives these hitchhikers a refuge

from other predators.

When conditions are right,

jellyfish numbers can explode.

Gathered into seasonal swarms by the swirling tides,

they drift north with the current.

For the next 500 miles,

the mainland is protected from the turbulent Atlantic

by thousands of small islands.

Behind this natural storm barrier,

there are calmer waters.

Stronghold of one of Scandinavia's most iconic creatures.

The white-tailed sea eagle,

riding on massive 2.5 metre wings.

Odin was said to transform into an eagle

to survey his realm.

And these sharp-eyed opportunists don't miss a trick.

EAGLE SQUAWKS

Swooping down at 40mph,

they must time their grab to perfection.

Curved talons and spiny scales on their toes

help grip slippery fish.

Catching a fish is one thing.

Keeping hold of it quite another.

Distinguished by its mottled tail,

this young sea eagle is pushing his luck...

EAGLE YELPS

..but has little chance against the flying skills

of an adult.

Whilst youngsters are perfecting their fishing technique,

piracy is a short cut to a full stomach.

Especially when the victim is another juvenile

more easily intimidated into dropping its catch.

A fish can be won and lost

many times in the chaos of a chase.

And things don't always go to plan.

These novices still have a lot to learn

before they match up to an adult eagle.

In the last century,

these majestic eagles were almost hunted to extinction.

Now protected across Norway,

the population has grown to over 6,000 mature birds.

Which means there's little chance of a quiet meal

as gangs of hungry youngsters gate-crash the party.

These boisterous juveniles will spend several years

wandering the coast before finding a place of their own.

Whilst sea eagles seldom leave this maze of inlets and islands,

the search for fish takes others far out into the North Atlantic.

BIRDS SQUAWK

Captain Kjartan Gudmundsson commands the Drangavik

and her ten-man crew

as they trawl for cod off the coast of Iceland.

After being heavily overfished,

careful management and strict quotas

means this fishery is now considered sustainable.

Fishing is in the captain's blood.

The open ocean is unforgiving.

But the crew must set and retrieve the net

whatever the weather.

Even with the latest technology,

it takes all his experience to put the Drangavik

in the right place at the right time.

Just three successful trawls can fill the ship's hold

and allows Kjartan to set course for home.

The richness of these offshore waters

owes much to a powerful current

that sweeps across the Atlantic from the tropics.

Every second, the Gulf Stream delivers nine million tonnes

of warm water into these northern seas -

enough heat to keep sea temperatures

along the Norwegian coast

much warmer than other places on the same latitude.

The Lofoten Islands are over 100 miles

inside the Arctic Circle.

Yet, here, the sea never freezes.

Communities cling to the narrow shores.

Huddled around inlets that offer safe haven all year round.

Most coastlines this far north will be locked in ice

for six months.

But warmed by the Gulf Stream,

winter sea temperatures here are kept a few degrees

above freezing.

Just enough to support some surprisingly busy sea life.

Sea cucumbers emerge to feed in the current.

They trap plankton and algae in their feathery tentacles.

Each taking turns to push food into its central mouth.

Starfish gather together in large numbers.

On cue, they raise themselves up on tiptoes.

Standing tall in the current,

they synchronously shed millions of eggs

and clouds of sperm.

These mix in the swirling water

before the fertilised eggs and larvae

are carried away with the flow.

Through the winter, the Gulf Stream keeps the sea from freezing.

But its heat doesn't reach far into some northern fjords.

Where rivers drain into these inlets,

the cold, fresh water can freeze,

forming a shelf of ice.

A welcome hunting platform for an otter.

And it's landed a prize catch.

But out on the ice, this otter is exposed.

OTTER SNARLS EAGLE YELPS

A young sea eagle up to its old tricks.

Time to take evasive action...

..until the coast is clear.

These Norwegian otters live further north

than any others on the planet.

Benefiting from the relatively mild climate

and the wealth of sea life nurtured by the Gulf Stream...

..these otters survive hundreds of miles

inside the Arctic Circle.

Lofoten fishermen exploit the unique local climate

to preserve their catch of spring cod.

During the annual Lofotfiske season,

fish are hung out to dry on huge wooden racks.

These fillets and fish heads don't need smoke or salt

to preserve them

because the Gulf Stream keeps the air temperature

just stable enough...

..to stop them from rotting

as they dry in the sun and wind.

It's a 1,000-year-old tradition dating back to the Vikings

who traded these dried fish all over southern Europe.

RACKS CREAK

By the end of the season,

these racks will be groaning under the weight

of thousands of tonnes of fish.

The riches of this coast destined to be shipped

all around the world.

Journeying to the very north of mainland Scandinavia,

the coast becomes wilder and even more unpredictable.

The Gulf Stream meets its match

as it comes up against the chilling Arctic Ocean.

This powerful collision can generate violent storms,

massive surges that churn up nutrients from the deep.

After spending the winter far out to sea,

tens of thousands of sea birds converge

on the island of Hornoya.

It's the bounty of these waters that support

such ravenous gatherings.

Huge rafts ride the swell...

..until it's time to make landfall

to nest and raise their chicks.

This is one of Scandinavia's most magnificent

wildlife spectacles.

While 30,000 guillemots pour in to claim a pitch

on the narrow ledges,

puffins head for the windswept lower slopes.

Returning birds seek out the nest burrows

they've used in previous years,

even if they are still buried under the snow.

And these are where partners will meet up again

after their long winter at sea.

Rubbing beaks reinforces their lifelong bonds.

As the weather clears, more birds join the throng...

..including a puffin rather late on the scene.

While all over the colony, birds are settling in,

he faces an uphill struggle.

With 8,000 puffins nesting on Hornoya,

the slopes are already crowded.

He must navigate

through this increasingly fractious crowd

to his old nest hole.

With burrows always in short supply,

everyone is ready to defend their patch.

He keeps his head down,

hoping to avoid any trouble.

But he's unwittingly strayed into dangerous territory.

A gaping beak is a warning.

And the wider the beak, the angrier the puffin.

And puffins fight dirty.

His burrow is up there but, without reclaiming it,

his chances of nesting this year are over.

Dusting himself off, he tries again.

He spots a familiar landmark.

His mate has beaten him home.

And she's already taken possession of their old burrow.

Life this far north is never predictable but, reunited,

they now have a fighting chance of raising a chick.

Just when this coastline seems at its most inhospitable...

..its greatest secret is hidden beneath the waves.

In the darkest months, Atlantic herring migrate

into the northern fjords to escape the worst Arctic weather.

A single shoal can contain three billion fish.

Such abundance does not go unnoticed.

Orca, killer whales.

In a deadly game of hide and seek,

they use echolocation to track down the big herring shoals.

Following in their wake is biologist and photographer Audun Rikardsen.

He's spent years piecing together

the lives of these formidable predators.

And he takes a very hands-on approach.

- If you are a visitor in their world and if you go down there,

then you can really feel the contact.

And those moments are really precious.

You can imagine what they do beneath the surface but, to really see

what's happening here, you have to go underwater.

For me, that's crucial, both as a scientist and as a nature

photographer, where you can use your picture to tell

better your research and you can use your research

to take better pictures.

- One herring isn't even a bite-sized snack for an orca.

But here, these clever whales have developed a unique hunting

technique to turn an appetiser...

..into a feast.

It's called carousel hunting.

Operating as a pack, they go to work, coordinating their attack

with pulsing calls.

- In fact, it's the older females, the grandmothers, that are the boss

in these family groups.

They know exactly what they should do when they work together.

- ORCA CALLS

Using air bubbles and belly flashes,

they herd the fish into a tight ball and drive them

towards the surface.

ORCA CALLS

While some corral the fish, others drive into the swirling mass,

whipping their tail to stun the herring.

Then each is delicately eaten one at a time.

But orca aren't the only clever predators here.

Humpback whales have begun tracking the orca's every move.

By listening in on their calls,

they know when a shoal has been rounded up.

And that's their cue to muscle in, rising from below to engulf

hundreds of fish in a single mouthful.

WHALES BRAY

In response...

..the orca have started eavesdropping

on other herring hunters.

From miles away, they have learned to tune in to the noise

of fishing machinery.

A trawler's winch is like a dinner bell.

The fishermen work at nights when the herring rise

up from the deep.

The nets are already full, but the orca are patient.

As the catch is hauled aboard...

..any strays and spills are easy pickings.

There's not enough to satisfy a humpback,

so the orca feed undisturbed.

Well, almost.

Audun has caught up with the orca.

Their presence around the trawlers gives him the perfect opportunity

to delve deeper into their changing world.

- So, what we want to do is to follow constantly and see what they do.

And doing that, you have to have a tag on, a satellite tag.

These are going to report positions for hopefully up to three months.

So then we can follow the herring and we can see if these killer

whales are following the same pattern as the herring.

OK. - OK. - Let's get it up.

- Success will take patience and skill.

- Yes!

- CHEERING

- That was good. That was really good.

- The tracker allows Audun to see just how much the orca depend

on the herring during their migration

through these northern seas.

- There's no-one that's better than the orcas to follow the herring.

So, if you have a good overview of the migration of the killer

whales, you will also have a good overview of the change in migration

patterns of herring, which is important for conservation.

- Over the last 20 years, orca have followed the main herring shoals

as they've shifted their winter base almost 200 miles further north...

..a move coinciding with a one degree Celsius rise in the average

sea temperatures here.

To survive on this unpredictable coast has always demanded

adaptability and resilience.

In a warming world, these qualities will be tested as never before...

..as all face up to the latest challenges

on Scandinavia's wild frontier.

Over an eventful year,

the Wild Scandinavia crew filmed along an epic coastline.

But to capture the drama of puffin life, they had to travel to Hornoya,

off Norway's Arctic coast.

- Made it! Woo!

- The crew must carry everything they need for the next 12 days

up to their base at the island's lighthouse.

- Incredibly grateful for the guys from the Norwegian Army,

who have come over to help us move this kit. - Come on, hurry up!

- Each day, the team must hike down the icy path to the bottom

of the bird cliff.

But on this wild coast, the weather is constantly changing.

A storm is never far away.

- Puffin spotting in the snow in a blizzard.

- The conditions are putting off most of the birds.

But a hardy few are brave enough to endure the storm.

- We've got puffins on the ground.

- But they don't seem to be in the mood for fighting.

- Wind has really gotten strong this afternoon,

so we're going to pack it in and call it a day.

- Buffeting winds make the icy path even more treacherous...

..and it's a long drop down the sheer cliff...

..a close call and an exhausting walk back to the lighthouse.

All the team can do is watch...

..and wait.

Finally, the storm subsides.

- Can't believe it.

At the moment, there's I don't know how many birds,

but it's just a cloud of guillemots going around in a big circle.

It looks like a huge, chaotic roller disco in the sky.

- And they're not alone.

- We've got puffins.

They just keep coming.

Within the space of about half an hour, almost the entire population

has landed on the cliffs.

- With the puffins now on the slopes in numbers, Jesse begins to get

a taste of their charming personalities.

- There's lots and lots of interactions between the birds.

They're sort of strolling around, either in pairs or...

Urgh! Oh, no!

Right in my mouth. There's a lot of birds flying over and I opened my

mouth at the wrong moment.

- HE COUGHS

It soon becomes clear why the birds keep flushing off the cliff

and over the crew's heads.

- There's two white-tailed eagles hunting on the cliff above us.

- Eagles pose a very real threat to the birds here.

But they're not the biggest challenge they face.

No-one understands this better than scientist Tone Reiertsen,

who has been studying the birds here for almost 20 years.

- It's worrying to see these warning signs now that things are changing.

The puffins, they tend to arrive earlier and earlier

and this is linked to the rising sea temperatures.

It looks like the Barents Sea has risen by one degree,

which doesn't sound very much, but it can have quite dramatic

consequences. The food and everything for the whole

marine ecosystem, actually.

So, if the food changes, then they simply cannot bring

up a chick.

We focus on trying to understand how they are adapting and how much

they are capable of adapting, but there is so little we know yet.

We need to find out more. We are running out of time.

- As the puffins stake out their old nests, Jesse is finally

able to film the battles for burrows that the team came here to witness.

- Having had no fights for days and days,

it's all kicking off today.

And you just saw it there. I mean, amazing.

And they're really going for it.

Oh, another fight! Another fight!

- Slow motion reveals just how intense these fights are.

- You see, sometimes they grab bills.

One of them does a karate kick right in the other guy's eye.

- But even with many burrows still buried, Jesse's noticed

they still seem to know where to find them.

- They kind of walk around a bit.

They're orienting themselves and trying to work out exactly

where their burrow is under the snow.

- Yeah, puffins, like all other sea birds,

they have an enormously good sense

of space so that, when they come back, even if there is one metre

of snow, they know exactly - this is my spot.

- It seems to me like a really silly thing to do for a bird

to have a fight on a cliff.

- The value of the nest site is very important for them.

These are very aggressive birds, actually.

I used to call them the most angry birds in the world!

- After a punishing start, the birds have made a powerful impression

on this team. - They're really magical little things.

I'm not sure I like them very much. Quite aggressive, but they are cool,

you've got to admire them.

- I've never been to anywhere with so many birds. It feels so alive.

But, sadly, the truth is that life for these birds

is becoming increasingly unpredictable.

And I just hope that we can slow that process down so that these

amazing birds have time to adapt because places

like this are just too precious to lose.

- Next time, we explore the magical forests...

..and the labyrinth of waterways

that are the heartlands of Scandinavia.

A secret world where ancient alliances connect all life...

..as animals and people face the trials

of the ever-changing seasons.

In the far north of Europe is a land steeped in myth...

..the realm of Thor...

..and Odin.

From Norway's frozen wilderness...

..deep into magical Swedish woodlands...

..across Finland's water world...

..to explosive Icelandic volcanoes...

..Scandinavia's breathtaking landscapes

have shaped its people...

..and its wildlife.

At its heart, enchanted forests wrap around a maze of waterways.

It takes surprising and intimate relationships to

survive in this ever-changing, seasonal world.

BIRD CALL

In Norse myth, there are tales of a mighty sacred tree...

..Yggdrasil.

Its trunk was at the centre of the cosmos...

..while its branches reached up to heaven...

..and its roots extended into the underworld.

Great forests are still at the heart of Scandinavia.

160 billion trees thrive in this northernmost woodland...

..part of the vast Boreal forest that fringes the Arctic.

Here, bowed spruce

stand like Ice Giants of Norse legend...

..enduring a winter of five long months.

They wear a coat of tykky...

..layers of ice crystals grown from the freezing, moist air.

And they're highly adapted to these extremes.

Flexible branches carry the heavy, insulating snow...

..while within, natural antifreeze protects their tissues.

These fairy-tale trees are masters of resilience.

But all who live here must find their own way

to survive the tough winter.

Clever tricks and partnerships work for some.

Ravens were said to be

informants to the Norse God Odin.

They scoured the world for gossip to bring back to their master.

RAVEN CALLS

But for these vocal birds, food is the only topic of conversation.

And word has spread fast,

drawing in a crowd.

RAVEN CALLS

With the carcass frozen, they can't break in...

..but their commotion attracts... just who they need.

A Golden eagle...

..Scandinavia's most powerful raptor.

It knows that where there are ravens, there's food.

Six times their size, an eagle can easily kill a raven.

But there are benefits to inviting your adversary to dinner.

The eagle has the tools to open up the carcass for them...

..if only they can sneak back to the table.

But their dinner plans are cut short.

More eagles arrive to claim their share of this feast.

All the ravens can do is watch...

..as these titans battle it out.

Eventually, a new victor emerges.

It's able to eat its fill, undisturbed...

..and finally allows the ravens back to the opened carcass.

This fleeting alliance of brains and brawn, benefits them all.

Some relationships here are so deeply entwined,

it's hard to imagine one without the other.

Margret Fjellstrom is an indigenous Sami reindeer herder.

Her family have depended on the reindeer for generations.

- The reindeer provide me food,

it provides clothes,

but it also provides me

contact with nature, with my ancestors and my future.

It's who I am.

- Margret must keep her herds alive through harsh winters, where

temperatures can plummet close to minus 40.

It's essential the reindeer get energy-rich food...

..particularly the pregnant females.

And to find it, they must seek out the Heartlands' oldest forests.

Margret and her family use snowmobiles,

steering the herds up to 30 miles a day, to the best grazing spots.

SHE CALLS

The reindeer need help from the Sami,

as their traditional migration routes are often blocked

by roads, towns,

and wind farms.

- The infrastructure of the land

has changed.

So, we need to guide the reindeers around

and find safe places for them.

- On their journey, the herds pass through new growth plantations...

..but these areas have little nutritious food to offer them.

It's the forests with trees over 100-years-old

that have what they desperately need...

..lichen.

During the winters, they make up 80%

of the reindeers' diet.

They eat a dozen different varieties.

With their excellent sense of smell, reindeer can detect them

a metre beneath the snow.

Lichens may look like plants,

but they're actually an ancient partnership between algae and fungi.

And as many grow just a few millimetres a year,

it takes decades for lichen-rich forests to develop.

But now, they are becoming more scarce.

- I see this forest.

It was all over and it was

a thick layer of lichens.

It was like to walk on soft, soft cotton.

But the lichen is burned by the sun.

- More than 70% of Sweden's age-old woodlands

have been cleared in the last 60 years...

..threatening the balance that sustains the Sami way of life.

- Now, we are using the forest faster than the forest can provide

and grow up. That's the problem.

Because if the lichen forest is disappearing,

the reindeer will starve to death.

- Some winters are more challenging than others.

But when Margret's reindeer reach the food they need,

it makes it all worthwhile.

- When I see the reindeer is grazing outside

and it's good condition, it's like a big love story.

You get all tickly in your body and you're smiling.

It's the best feeling.

You know, when you're in love, really in love, that's the feeling.

- Margret has always had a special relationship with the reindeer...

..which will continue with the next generation of calves in the spring.

As the days become longer, winter begins to

loosen its stranglehold.

But within the forest, this boggy clearing is still frozen

and carpeted with snow.

Every April, it becomes the focal point of one Scandinavia's

most flamboyant wildlife spectacles.

ANIMAL CALLS

As dawn breaks...

..a distinctive bubbling sound carries through the air...

..war cries of male black grouse.

THEY SQUAWK AND SHRIEK

DRAMATIC MUSIC PLAYS

They're here to compete for mating rights to the mottled brown females.

On this battleground, known as a lek,

there's a distinct hierarchy.

And in the centre of it all is the King.

He's the champion fighter,

flaunting the biggest scarlet eye combs...

..and finest lyre tail feathers.

Popular with the hens, he wins the most mates.

But every male wants his success.

Threats come from all sides.

Novice males, are just learning the ropes....

..and are easily intimidated.

Others, he must fight to assert his dominance.

SQUAWKING AND SHRIEKING

SHRILL SHRIEK

But there's one battle-scarred male who's a serious challenger.

This old timer has sacrificed many

of his fine feathers in combat...

..and isn't satisfied with a place on the edge of the action,

watching the hens pass him by.

He challenges the King to a duel.

Both are heavy-weights, at almost 2 kilos,

and closely matched.

DRAMATIC MUSIC PLAYS

The old timer rips out

a clump of chest feathers.

The King retaliates.

The battle goes on for almost an hour.

Both sustain stabbing injuries to their chests...

..until the King deals the final blow.

Injured, the old timer is defeated.

The King grouse retains his title...

..and is eager to make good on his victory.

His reward?

To mate with over half the females on this lek...

..as the snow begins to thaw...

..exposing the peaty bog once more.

Across Scandinavia's Heartlands,

spring heralds a time of magnificent transformation...

..the Great Melt.

Water is liberated from the mountains...

..into fast-flowing rivers and streams.

Some of the world's most spectacular waterfalls

are found in Scandinavia...

..cascading through the landscape...

..and filling hundreds of thousands of lakes,

carved from rock during the last Ice Age.

For Swedes, Varkanslor,

or spring fever,

begins with returning migrant birds.

GRUNTING

Moose are also on the move,

following long-standing migration routes towards new pastures.

In the forest canopy,

warmer days trigger the pine cones of Norway spruce

to ease open.

Just one tree can release tens of thousands of seeds every year.

But only a few will survive to join the Heartlands giants,

standing up to 40 metres tall and living for 600 years.

Over half of Scandinavia is covered with trees...

..and ideas of the forest

have always been entwined in Norse folklore...

..fabled to harbour many mythical creatures.

There are tales of trolls...

..murderous giants...

..and dangerous seductresses.

One forest animal was renowned as the companion of Freyja...

..goddess of love -

..the lynx.

It's Europe's biggest and most elusive wild cat.

LYNX CALLS

But its scream isn't as sinister as it sounds.

It's the mating season

and this roving bachelor is looking for love.

He searches for special trees that could help with his quest.

He rubs his body all over the scaly trunk of this Scots pine...

..releasing odour from glands on his cheeks and paws.

A "love letter" to receptive females

and a warning to other males.

His signature is etched into the bark and sealed with his scent.

The textured surface will preserve his smell for weeks

and even snags a lock of his fur.

He continues his patrol...

..leaving fragrant messages on distinctive landmarks.

Lynx travel up to 30 miles each day.

Over 3,000 of these rare cats

wander the Heartlands of Scandinavia.

LYNX CALLS

Hopefully, a female will hear

or smell him...

..as he roams his vast territory

of 300 square miles...

..weaving through forests,

increasingly fragmented...

..by human expansion.

During spring, the weather is still changeable.

A passing storm...

..brings fresh snowfall.

And there's a glimmer of hope.

A beautiful female lynx

has taken a keen interest in the male's aroma

preserved in the tree's craggy bark.

She's smaller than him, with lighter fur,

and sprays her own calling card

as a reply.

It can take a lynx two weeks to patrol his territory...

..but this male returns to some good news.

The female's lingering perfume reveals she was here recently

and she's in season...

HE PURRS

..much to his delight.

PURRING

With the help of this distinctive gnarled tree,

this lynx has finally had his love letter answered...

..and hopefully his chance to meet her face-to-face

is just round the corner.

Every creature here relies on the forest...

..and by late spring it is lush...

..and green.

After the long winter, this female brown bear...

..finally emerges from hibernation.

With her two young cubs,

she's amongst 5,000 bears

left in Scandinavia.

Their broad diet gives them an important role

as forest gardeners, spreading seeds.

And this mum will teach her cubs

over 70 different edible plants.

But they're easily distracted.

And always keen to play.

Mum knows there's one lesson that can't wait.

These towering pine trees could save their lives...

..but only if they can climb.

They will be their escape route out of danger.

Going up looks easy...

CUB SQUEAKS, MUM GROWLS

..but it's harder coming down.

Mum encourages them from below.

SHE ROARS

Training over,

the cubs snuggle in for a nourishing feed.

She has a couple more years to pass on her specialist

knowledge of the forest before they become independent.

The summer months bring longer days.

A brief season of plenty...

..and relaxation.

But some creatures never rest.

This woodland looks like a scene of destruction.

But it's only during twilight hours that the culprit emerges.

A Eurasian beaver...

..Scandinavia's largest rodent...

..over a metre long.

The beaver's an industrious engineer.

Building dams which flood the forest...

..he dramatically transforms the landscape...

..creating a water world so he can access his food in safety.

He dines on a vegetarian smorgasbord of bark,

branches, leaves, and shoots.

In serving his own needs,

he is the architect of this maze of secluded rivers and lakes.

The slower movement of water provides nurseries for fish

and underpins a rich diversity of life...

..including the osprey,

a specialist fishing hawk.

This male has flown over 4,000 miles from Africa...

..returning to this lake in southern Scandinavia.

He's now raising his two chicks solo...

..as osprey mums leave for Africa as soon as their chicks can fly.

He's a devoted parent.

Every extra day he stays and provides,

his fledglings will get stronger...

..but he must also keep the reserves

to make his own marathon migration south.

For now, his chicks still use the family nest as their base

and are completely reliant on him for meals.

With many years of experience, this dad's a pro at fishing...

..and the fledglings need to learn from him fast.

With exceptional eyesight, he pinpoints a fish...

..and dives at speeds over 75mph.

He works relentlessly...

..catching as many as ten fish a day...

..for his gluttonous chicks.

By early September,

it's time for dad to leave for Africa.

One last feed,

and his job is done.

His chicks will now have to manage by themselves.

In just a few days,

they'll begin their own epic migration to Africa...

..leaving these rich lakes quiet,

until ospreys return again next year.

At the end of summer, temperatures begin to fall

and days get shorter...

..triggering an explosion of brilliant autumn colours,

known as Ruska in Finland.

Deciduous trees like birch, aspen

and rowan show off their magnificent shades of yellow and orange.

While on the damp ground,

the forest's most fundamental relationship is revealed...

..fungi.

They erupt from the forest floor as mushrooms,

to spread their spores before winter returns.

CHATTERING

With almost 10,000 varieties across Scandinavia...

..many families have secret spots

where they collect edible mushrooms every year...

..expressing their Allemansratten, or every man's right,

to roam and forage in nature.

Mushrooms are all we can see at the surface of a massive underground

fungal network that links into the roots of almost every tree...

..and is vital for keeping the forest alive.

In this shallow acidic soil,

fungi have the key enzymes

to provide essential nitrogen to the trees.

But to do this, the fungi need fuel,

which they get from the trees as sugars, in this age-old association.

Without this foundation of fungi,

the landscape could turn to treeless tundra...

..but in partnership,

the boreal forests have been able to survive in the north.

Autumn is an important season for the Heartlands residents.

A short window of opportunity to stock up

before the cold arrives once again.

This male brown bear must pack on the pounds

before he goes into hibernation.

Over the next few weeks, he must eat 20,0000 calories a day.

And surprisingly, such tiny berries can meet most of his needs.

But he's not averse to a very different meal.

With a remarkable sense of smell...

..he can sniff out food from several miles away.

A wolverine is first to the feast.

This opportunist has no problem breaking into a carcass

with his powerful bone-crunching jaws.

But he's not the only diner.

RAVENS CALL

The ravens' noisy calls draw the bear closer.

THEY CAW NOISILY

He can eat as much as 40 kilos in one sitting.

But he needs to watch his back.

DRAMATIC MUSIC PLAYS

Wolves were Odin's mythical warriors,

and this hungry pack are on the offensive.

The bear is bigger and stronger than any wolf, but he's alone.

The ten-strong pack press closer.

Led by the alpha pair,

they work as a team to intimidate the bear.

SNARLING

He can't afford to abandon his meal.

One wolf tries to distract him away from the carcass.

GROWLING AND SNARLING

But the bear's determined.

He grabs whatever he can.

The wolf pack have the remains...

..but each must wait their turn to feed.

While this family is doing well,

wolves are Scandinavia's rarest carnivore.

Hunted under a strict quota,

there are fewer than 700 left.

These stealthy predators soon melt back into the shadows

and safety of the forest.

HOWLING

The formation of ice...

..and first dusting of snow,

heralds the return of winter...

..completing the seasonal cycle for life in the Heartlands.

But there are some who have been eagerly awaiting

the return of the ice.

Oskar Karlin is one of thousands of Scandinavians for whom wild,

or Nordic, ice skating is a consuming passion.

- Winter is something I really look forward to.

You want to be on the ice as soon as possible

because the first ice is the best ice.

- But as ice skating can be dangerous,

he needs to be absolutely sure the ice is thick enough.

- You say 3.2 centimetres is the thinnest you can skate on.

And when it's almost 10cms,

you can almost drive a small car on it.

- Oskar takes the lead, navigating a safe route across the lake.

- I would never ever skate alone. That's so dangerous.

It's important to be quite focused, cos you never know

if the ice is getting thinner, or what's going to happen.

Parts of your brain has to be

scanning the ice and looking for dangers.

- There are lots of different kinds of ice...

..but the holy grail

is newly-formed black ice.

It's smooth, clear and precariously thin.

- If the conditions are perfect,

when it freezes, it becomes like purely black,

and that's the most magical ice to skate on.

- ENIGMATIC PULSING BEATS

- The sound from the ice when it's quite thin sounds

very strange, almost like laser beams - tshoom, tshoom.

It's the sound from another world.

It's almost like watching the Northern Lights, but with your ears.

- EERIE PULSING CONTINUES

- Sometimes, when there's a little bit of water on the ice,

it feels like you're skating in the sky, or something,

because the reflections are incredible.

Living in the city, I love it, but it's quite hectic,

so when I come out, I'm not so stressed.

You constantly see this beautiful nature

and when you skate, you get happy from it.

So, the more you move,

the happier you get!

- Scandinavia's raw wilderness is exhilarating for those who

immerse themselves in it.

But this perfect balance in nature...

..is a fleeting and fragile one.

- The seasons, every year is different.

If the temperature just changes a few degrees,

then we will have almost no ice, so it's such a small variation

in temperature that changes the whole thing.

The more time I spend in nature, I realise how fragile everything is.

- This extraordinary world

with its countless intricate relationships

exists in a delicate balance across the seasons.

Today, it's becoming more fragile,

impacted by human pressures

and climate change.

Yet, just as the legendary tree, Yggdrasil,

was the centre of the Norse universe...

..forests still play a vital role...

..interconnecting life.

They are the living, beating heart of Scandinavia.

The Wild Scandinavia team filmed in the Nordic Heartlands over

the course of a year,

braving the mosquitoes...

..cold water...

..and thin ice.

Using state-of-the-art cameras and innovative techniques,

the crew captured the dramatic behaviour...

..of some of Scandinavia's most iconic animals.

But perhaps the most challenging of the shoots was filming with

a family of Sami reindeer herders in Sweden.

The film crew had to cope with extreme winter conditions

to get their shots.

- I'm just about keeping feeling in my fingers with some hand warmers.

My water has succumbed to the cold!

- Traversing with deep snow is tricky.

I don't know how the reindeer do it.

Deep snow! God!

Oh, my God!

- Pull you up by this?

Woo-hoo!

OK, pull!

- LAUGHTER

Margret and her family take great risks, crossing frozen lakes

and difficult terrain to guide their herds

to the precious lichen forests.

As the reindeer move fast over long distances,

the only way to keep up is by snowmobile

and Margret learnt to drive one when she was just five-years-old.

- This machine is going really, really fast.

And you can hurt yourself really, really bad on that.

- The crew need to learn how to handle one safely.

- Start.

Gas.

Brake.

Yes. Ready?

More, more, more.

Not so fast!

When the snow is deep,

you always get stuck.

When I teach people,

I force them to get stuck in the snow.

And if you don't know how to get loose,

when you get stuck, it can be dangerous.

Everybody need to come here and help.

One can take there.

- It's essential that the crew work as a team.

And with Margret's training,

they're ready to deal with the challenges ahead.

- Yeah, we're in. - Victory!

They did really, really good, this crew.

They are not afraid of speed. That's a good thing!

- The crew can now get to work,

following and filming the Sami, as they herd their reindeer.

They see for themselves just how tricky it is.

- It's very difficult. They're just sort of completely scattered

through the forest.

They're like water, they just flow everywhere!

- Margret makes it look easy.

- Really cool, see how she moves the reindeer and herds them and...

It's like cowboys in the snow! Amazing!

I want to be a Sami now!

- But the job of a reindeer herder has got even harder in recent years,

particularly with a changing climate.

The average temperatures in parts of Sweden have gone

up by a couple of degrees Celsius over the last 30 years.

- You can have three seasons

in one month. That's never happened when I was growing up.

The skills that I learned from my fathers about weather

is not working any more.

It's really, really

hard to predict where should we go,

for the best grazing.

We never know. We have to move them

all the time in the winter.

- With such unpredictable weather, Margret

and her husband, Daniel, have had to adapt...

..and have found a novel way to herd the reindeer even if there's

not enough snow to use snowmobiles.

- We use the drone. It's an easy way to

get a hold of where they are.

And it saves time.

- Daniel broadcasts some intriguing recordings from the drone's

loudspeaker to get the deer moving.

SIREN-STYLE ALARM

BARKING

- That's some dog from the internet.

- BARKING CONTINUES

- This is the Tasmanian devil, apparently.

- STRANGE ROAR AND HOWL

- You have to use that carefully

because they can get really, really scared.

And you can record your own voice

and play it up in the drone.

- HE CALLS

RECORDING PLAYS

- It's about the same as when you drive a snowmobile.

You just point them in the direction you want

and just go round them like this, holding them together.

- Out of the 70,000 Sami that live within Arctic Europe,

only 10% of them still herd reindeer.

But despite this dwindling lifestyle, Margret's

18-year-old daughter Alva is keen to continue the tradition.

- I will want to go out in the forest and work with the reindeers,

full-time.

Here, I get to be outside, I get to see the

animals that I really love.

You can just see a reindeer one day by the road

and you make it go to the forest and then you feel like a superhero.

- Although the Sami herders of Scandinavia

face many challenges today...

..Margret and her family have found ways to modernise

and adapt their traditional way of life...

..retaining their close alliance with the reindeer, which will

hopefully continue far into the future.

Next time, we travel to Scandinavia's extremes...

..where the long, dark, polar night...

..melts into a sleepless rush of life under the midnight sun...

..in the kingdoms of ice...

..and fire.

In the far north of Europe is a land steeped in myth.

The realm of Thor...

..and Odin.

From Norway's frozen wilderness...

..deep into magical Swedish forests...

..across Denmark's windswept shores...

..to explosive Icelandic volcanoes...

..Scandinavia's breathtaking landscapes...

..have shaped its people...

..and its wildlife.

At the extremes, Scandinavia gives way to a kingdom of ice...

..where the long dark polar night...

..melts into a sleepless rush of life...

..under endless summer light.

To survive here,

animals must navigate the most dramatic seasonal shifts on Earth,

driven by the power of the sun.

Scandinavia's far north is in the grip of winter.

Lonely mountains and isolated Arctic islands...

..are locked under the weight of snow and ice.

These are Scandinavia's most remote places.

Starved of sunlight in winter and plunged into the bitter cold...

..often reaching lows of -20C.

There are not many creatures who can bear this long, dark season.

But for those who stay, this is a final stronghold in a warming world.

Winds over 100mph greet the muskoxen

of Norway's remote mountains.

They are a relic of the Ice Age, unchanged for over 600,000 years.

Layers of thick fur shield them from the vicious weather.

Herding together, they're at home in the long winter.

But even in the gloom, the sun does not let the North forget her.

93 million miles away, a solar storm is raging.

Electrically charged particles burst from the sun's surface...

..and hurtle towards Earth.

As they reach our planet,

the attack is deflected towards the poles by Earth's magnetic field.

But some particles break through to the atmosphere

and react with gases in the sky...

..igniting the lights of the aurora borealis.

Only in the darkness can they be seen in their full glory.

Icelanders call them Nordurljos, the Dawn of the North.

They are a reminder that the sun will soon return.

On the western edge of Scandinavia lies the island of Iceland.

Only a few miles below the Arctic Circle,

the Hornstrandir peninsula spills out towards the North...

..in a series of dramatic fjords...

..and vast tracts of tundra.

In February, the late winter heaves thick sheets of snow and ice

downhill towards the sea.

Small patches of berries from last autumn...

..are uncovered in the weak sunlight.

A morsel for Iceland's only native mammal...

..the arctic fox.

Her fur is thick enough to tolerate temperatures as low as -45C.

But it's not the cold that she needs to worry about.

Prey is scarce in the winter months...

..and a few berries are not enough.

It pays to keep an eye on the tides.

To survive here, arctic foxes must scavenge on the shoreline.

But on the edge of Iceland, foraging is not always easy.

Every day that the sun grows stronger,

the cliffs of snow edge towards collapse.

A formidable descent lies between her and her only hope of survival.

She can't afford to miss low tide.

There is no choice but to go down.

Hornstrandir's coast is revealed for just a few hours...

..and ravens have already arrived.

She works quickly,

trying to find something they might have overlooked...

..before the tide cuts her off.

Every metre of the beach is explored.

This time, the strong currents have provided what she needs.

A sea urchin is a lifeline.

In summer, these cliffs will come alive with nesting birds...

..and her resilience will be rewarded.

As the earth shifts, the sun grows stronger.

For an arctic fox...

..the change can't come soon enough.

In Iceland's highlands,

the lengthening daylight does little to thaw the hills.

In March, this is still winter's kingdom.

Each year, this is the first place to greet the cold...

..and the last to say goodbye.

But it's not as deserted as it seems.

Bryn, Thorey and Birna are no strangers to the cold.

These three friends take on a winter expedition every year.

- I really love bad weather, there's something healing in it.

It's just you against the elements. It's great.

- Crossing hundreds of miles over a single weekend,

they set aside any fears to navigate over hidden rivers...

..across buried crevasses...

..and creep beneath heavy banks of snow.

In exchange, they are liberated from life's usual routines.

- For me as a woman, allowing me to have interests,

to have something else than just being a mother

and just being a good employer...

..I wanted to just put more adventure into my life.

- On these trips they are self-reliant,

carrying everything they need...

..and hours away from rescue.

- I like navigating, and that's my...

My strong suit is navigation and reading maps.

Slowly, slowly you build up the experience...

..and you get more confident.

- But survival isn't just about mastering the conditions.

- It's a feeling of freedom.

I think freedom is the strongest feeling I feel

when I travel like this.

- With daylight fading, their intended destination comes into view...

..Iceland's hot springs.

No trip to the highlands should be without this vital luxury.

- The hot springs are a treat all year round,

but especially so in the wintertime.

You find a hot spring and just soak it in and warm up.

- There are geothermal hot springs all over Iceland.

The waters here are 40C

and rich in minerals thought to have healing properties.

- You're a bit tired after the challenge

you've taken on during the day, and it is the most amazing feeling.

- These hot springs are known in Icelandic as Landmannalaugar,

'the people's pools'.

For centuries, they have been used as a rest spot for weary travellers.

Little has changed.

These hot springs are an oasis in a desert of snow,

but humans aren't the only ones here soaking up the warmth.

Hidden amongst the mosses,

a surprising creature stalks the undergrowth.

Laugakongulo...

..Iceland's pool spider.

Only the size of a thumbnail,

these spiders are amongst the smallest of the wolf spider family.

They're found all over the world.

Normally dormant in the winter...

..here they live a very different life.

The constant heat allows these spiders

to defy the seasonal clock...

..thriving, even in the middle of winter.

But there are limits even here.

Wolf spiders must walk a perilous line

between the worlds of ice and fire.

One wrong step means being boiled alive...

..or swept away in the current.

Not everyone lives to see the summer.

But stray too far from the hot springs...

..and a much colder death awaits.

Luckily, their prey is also marooned.

These flies are hot spring specialists,

feeding on nutrient-rich algae.

Wolf spiders earned their name

from their predatory hunting technique.

It's sometimes hard to see the association.

Even the most hopeless spider gets lucky sometimes.

They might not be agile hunters, but in this warm oasis,

they have the luxury of time.

The hot springs across Iceland are a sanctuary from winter.

But the volcanic forces that have created them...

..are as powerful as they are unpredictable.

Since the history books began,

Iceland has been a land dominated by ice...

..and fire.

Though they coexist, it's fire that reigns here.

Iceland has over 100 volcanoes.

Magma is the lifeblood of this island...

..able to thaw Iceland's coldest winters

and unleash ash clouds that turn day into night.

More explosive eruptions of the past

might be behind the words of ancient poetry.

Sol ter sortna - the sun turns black...

..leikr har hiti - flames fly high...

..vid himin sjalfan - as if against heaven itself.

Nowhere else in Scandinavia can the Earth defy winter with such success.

Bur warmth is a distant memory in the far North.

At Scandinavia's extremes,

the frozen islands of Svalbard lie deep inside the Arctic Circle.

Here, the brutal winter has been one long night.

But by March, the sun finally returns.

In just one month, the daylight swings from one hour to 12.

Spring has finally begun.

The sun's reappearance ignites a dormant lust in male polar bears.

This male is now entirely devoted to finding a mate.

He might have to travel hundreds of miles to find a female...

..and in the vast frozen landscape,

there's only one way to track down romance.

He must follow his nose.

Scent glands on polar bears' feet mean that every footstep they leave

encodes their identity on to the ice...

..and he's following the faint footsteps of a female.

After days of pursuing her...

..there she is.

Finding her is only half the challenge.

Polar bear courtship is anything but simple.

Males are usually so aggressive

that females spend most of the year

avoiding them.

If he wants to win her trust,

he'll need to turn on the charm.

Because it takes so long for a polar bear couple to meet,

her ovulation will only be triggered after several days of his company.

And it'll take much longer than that for his efforts to bear any fruit.

After a winter alone, he's willing to take on the challenge.

South of Svalbard, across the freezing Barents Sea,

the northern tip of Norway is a patchwork of tundra and snow.

In mid-May, sunset merges into sunrise

for the first time in the year.

The sun won't set again for another eight weeks.

It's a silent starting pistol

that will transform the Arctic landscape...

..and its animals.

Stunted willows provide the first nectar of the season...

..and a song post for migrant birds from the south.

But the tundra's most extravagant visitors have just arrived.

Male ruffs...

..desperate for attention.

This is a lekking ground.

Here, males defend their own tiny patch of tundra,

performing elaborate dances to seduce their female audience.

With 24 hours of sunlight,

this performance goes on through the night.

Whenever boundaries are crossed, fights break out.

But there are some who don't play by these rules.

Ruffs with white feathers are genetically different.

They will never hold a dancing patch of their own.

They're less aggressive than the other males...

..and perhaps that's why...

..the dominant dancers tolerate their presence.

They even co-ordinate dance moves for a more dazzling display.

But white ruffs have their own mating strategy.

He'll endure the leading male's ego

if it means he can get a little closer to the ladies.

But too close...

..and he's quickly put back in his place.

He'll need to be a little sneakier.

Perhaps he can trick this orange-maned male?

But he's not the easiest dancing partner either.

BIRD CHIRPS

An intruder interrupts.

This is his moment.

The white ruff steals the show...

..and there's nothing his competition can do about it.

He'll take every chance he can get.

And with endless daylight on his side,

he has plenty of time to push his luck.

Throughout June, across Scandinavia...

..as each day grows warmer,

the landscape becomes almost unrecognisable.

The muted white of Iceland's highlands

gives way to a kaleidoscope of colour.

Meltwater braids across black volcanic sands.

Flowers rush from seed to bloom in a race against time.

In the ancient Norse calendar, these weeks of light

were known as Solmanuour, the sun month.

Even in Svalbard,

the stubborn remnants of winter are finally overthrown.

The sun is at the height of her power.

Temperatures climb up from their winter lows by nearly 30 degrees.

And this world of snow and ice

is unravelling at an unimaginable pace.

Every year, Svalbard loses 18 billion tonnes of water...

..and much of this water comes from glaciers.

In recent years,

glaciers across Svalbard have been behaving strangely.

Scientists know that the Scandinavian Arctic,

like most of the North, is undergoing a dramatic change...

..none more so than glaciologists like Dr Heidi Sevestre.

- My job is to study big monsters of ice, like this guy behind me.

I find glaciers endlessly fascinating.

They are absolutely beautiful. They are just mesmerising.

- Heidi has been studying glaciers for over ten years.

- Just another day in the office!

- Wahlenbergbreen is one of over 2,000 glaciers on Svalbard.

This is a river of ice, 16 miles long,

emptying into the sea.

- Glaciers in the Arctic are all being deeply affected by climate change.

The one we have behind us is quite a special one.

This glacier, five or six years ago, was almost completely static.

It was completely dormant. So slow, nothing was happening here.

And, simply, the glacier started to wake up and to accelerate.

This is a glacier that is currently surging.

- As the arctic heats up, Svalbard is experiencing more rain every year...

..which erodes through glaciers,

making them slip faster towards warming seas

in this process known as surging.

Heidi is here for the arctic melt season

to find out just how fast Wahlenbergbreen is moving.

- Time-lapse is really a revolution in the field of glaciology.

Making the invisible visible.

- The team leave the time-lapse cameras running over the summer

to monitor the glacier's movements before retrieving the footage.

- Using the time-lapse footage

and tracking some of the features in the ice,

it tells us that the glacier is moving

at about four to five metres per day,

which is super, super fast for a glacier of this size.

- For scientists like Heidi,

Svalbard is a glimpse into the future

for places far beyond Scandinavia.

- It is very important to have people to study what is happening here

because it's showing us what will happen

in the rest of the world in the decades to come.

- Because of climate change,

the Arctic is warming twice as fast as the rest of the world.

But Svalbard is warming much faster than that.

- We've seen glaciers in Svalbard that, as the result of a surge,

lost 80% of their entire mass.

- That is ice that the glacier will never recover.

- So what we are seeing here

is pretty much like a patient in intensive care

and all the alarm bells are ringing.

- Temperatures here are expected to warm by over ten degrees

by the end of this century...

..changing Svalbard beyond recognition.

But Heidi believes there is still hope for the Arctic.

- What's very clear is that you can never stop an ocean that is rising.

We have all the cards in our hands today to fight the climate crisis...

..and that makes me incredibly hopeful for the future.

- 20,000 years ago,

great sheets of ice covered the whole of Scandinavia.

Ancient glaciers carved Norway's mountain valleys.

But in the midday sun...

..the Ice Age is a distant memory.

And the muskoxen of Norway were not built for this heat.

With two layers of thick fur, the leader of the herd is suffering.

His rank entitles him to this harem of females...

..all mothers to calves that he has fathered.

But this mating privilege comes with responsibility.

He must protect and lead them until winter.

They can't stay in the hot, airless valleys.

Moving to higher ground brings relief...

..but it also means the muskoxen scattered across Dovrefjell

are slowly moving closer together...

..an unwelcome prospect for the male.

Late summer triggers the start of the muskox rut.

His position of dominance must be defended in battle every year.

A rival male.

This challenger knows he is an equal match.

Presenting his broadside demonstrates his bulk.

The defender won't tolerate such insolence.

They charge at speeds over 30mph.

Despite having a skull thicker than a brick...

..and a brain smaller than a fist...

..these impacts cause lasting damage.

They're too evenly matched to end the fight quickly.

Instead, they try to throw their opponent off balance.

The defending male times it right.

It's enough to finish it.

His legacy is protected...

..for now.

The muskox rut will only end at the first signs of winter.

Under the glare of the sun, he'll be tested to his limits.

Other arctic animals seem to be revelling

in life under the midnight sun.

In Svalbard, freed from sea ice,

the shoreline provides summer visitors

with round-the-clock feeding opportunities.

In Hornsund, the arctic's most numerous sea bird...

..is permanently dressed for dinner.

This war zone of rock is the seasonal home of the little auk.

Spending their life at sea,

little auks come on land for just a few months of the year.

Concealed between the boulders lies a badly kept secret.

Over 55,000 little auk chicks...

..hiding out of sight.

They need to grow up quickly and fledge

before the temperature drops below freezing.

They have just under four weeks.

Little auks mate for life and his parents are a team,

coordinating daily trips over 60 miles out to sea

to ensure their chick is never without food for long.

Raising young like this is a massive energy investment...

..so each pair will only have one chick,

one shot at parenting, every year.

But they are devoted to the cause.

Each day, the chick will eat half its body weight

in energy-rich zooplankton.

When he is not being fed, he's alone in the nest.

But there is always someone watching.

Glaucous gulls.

They are ruthless predators.

Suddenly, the nest made of rocks makes sense.

This is a fortress.

And enemies are everywhere.

As July gives way to August...

..the sun's power in the North begins to wane.

The temperature on land drops and fogs roll across the colony,

announcing the end of summer.

It's a warning that time is running out.

At just two weeks old, this little auk chick

must begin preparing for the flight of his life.

But it's too cramped in here.

He'll have to go outside.

The gulls pick off unwary chicks as they emerge.

Despite the risks,

he needs to exercise his wings before he can fledge.

This practice is vital.

The gulls ignite terror in the young chicks...

..but they must continue their training.

Every fledgling chick has a guardian for their first flight.

It's a nervous time for any parent.

Once they take off, they will have to head straight to the open ocean.

There's no turning back.

A young female is also readying herself.

And with some imperceptible signal...

..she's gone.

Not everyone can pluck up the courage so quickly.

Soon, pairs begin disappearing into the horizon.

True freedom.

And just in time.

By late August, Svalbard's slopes fall quiet once more.

The sun dips below the horizon for the first time in over 100 days.

Across Scandinavia, seasonal visitors depart...

..fleeing the coming winter.

Many who remain welcome the return of the cold.

Solitary polar bears are once again free to roam the expanding sea ice.

Muskoxen regroup into larger herds...

..to face the winter together.

Iceland's foxes wait for new treasures on the tides.

Over the next few weeks, the daily temperature drops to -10C...

..and the sun finally surrenders to the polar night.

The team spent a year

filming in Scandinavia's most extreme environments,

capturing some of its toughest and strangest characters.

But no shoot took the team further

than a trip to the High Arctic islands of Svalbard

to film little auk chicks learning to fly.

- It's just unbelievable, you know.

The sounds are just amazing.

You get, like, these big swooshes as they go over you.

It just sounds like the wind.

It's just so beautiful and electric, I'm just kind of in awe.

- To match the colony's peak activity,

the crew must work during the night hours.

It's almost midnight.

- It's beautiful.

I think the biggest challenge for me

will be the fact there's just so much going on.

- But the crew have help at hand.

Kasia Wojczulanis-Jakubas, from the University of Gdansk in Poland,

has been studying little auks for almost 20 years.

- Part of me treats them as data points...

..parts of me treat them like, I don't know, not even like pets,

but like family members.

- Every summer, Kasia and her team

monitor the behaviour and health of the little auks,

giving Declan a chance to meet one of this year's chicks.

- So how old's this little guy?

- Two weeks old. - Do they grow pretty quick?

How long do they have until they've got to leave the nest?

- They need three weeks to be fully developed

and then to fledge it's like four weeks.

- Good luck, little fella. I really hope you make it.

- DECLAN CHUCKLES

- They're so cute.

- In return, the crew are hoping to help Kasia see the chicks

as she has never seen them before.

- So I am just fitting this nest camera into the nest,

so we can get a view of the chick as he grows.

This is our view.

- Oh, yeah, there is a chick. - There's chick.

- Oh, so cool.

- And it seems one of the chicks isn't alone.

- There was another chick!

Come on, there is another nest!

- So they're neighbours, those little chicks!

That one just pooed right into his nest, which is very impolite.

- That's amazing.

The nest density is so big. Yeah, yeah.

This is so unexpected.

Oh, so cool.

- After a week under the midnight sun,

the crew are making great progress...

..and attracting interest from the locals.

- We've got distracted from the little auks

because an arctic fox has just been terrorising reindeer.

A* entertainment from the Arctic Tundra.

- As another filming night ends, time is ticking for the crew

to capture the moment a chick first takes wing.

- It's coming up to 5am now.

So we've got about five nights left,

and hopefully he'll fledge in time because he's late!

- And Kasia's observations are suggesting

not everything is right in the colony.

- Working here for almost 20 years, I can really say that this year

is very, very different from the others.

They started to breed the earliest ever.

And then, apparently,

they struggle a lot to get food to all their chicks

and it seems like they travel really, really far.

So it's like 100km.

- That's so much energy they're using. - Yes, it is.

- The most nutritious food can only be found in cold Arctic waters

that are becoming harder to reach in a warming world.

100km per mouthful is a big ask for a tiny bird.

- So they could keep struggling year on year? - Yeah, yeah.

You will always have better and worse seasons, but the thing is,

these worse seasons, they happen to be more and more frequent,

and this is very likely to be an effect of this climate change.

- The weather takes a turn for the worse...

..and the crew must retreat to the research station.

All they can do is wait.

- The headphones are going back on.

- The next evening,

a break in the weather brings a change in atmosphere.

- All of a sudden, it just seems a bit different.

The colony, they're a bit more... - Yeah.

- It's 8pm, and the crew spot a chick that's looking ready.

- I really think these two are hyping up for something.

- They should go tonight.

- Shall we just sit tight on them? - Yeah, yeah, I think so.

- To be in with a chance of capturing the moment,

the crew must focus on one chick.

He could fly any second, but it's a big gamble.

- He's just biding his time, isn't he? - Mmm.

There's going to be hours of this.

- Yeah. This guy's nervous. I'm nervous too, actually.

- You would be nervous though, wouldn't you?

I know it's a nerve-racking time but you've got to do it.

Bite the bullet.

- After seven long hours...

- Ooh! - Ooh!

- ..they finally have their shot.

- Whoa! That was stressful.

- All right, let's find the next one, then!

- HE LAUGHS

- It's four in the morning, isn't it? - Yeah, it is.

- With chicks fledging in their droves and more shots in the can...

- Yeah, so cool!

Perfect angle, perfect moment!

- ..it's finally time for the crew to leave.

- The little auks, I loved them.

I loved watching them finally have the courage.

I'm definitely going to miss this place. It's very special.

- I feel really quite attached to the fledglings.

When we've been watching them go,

I can't help but wonder how scary it must be

to go from your safe little nest to the wide open ocean.

Tonight is quite a good example of Svalbard's famous fogs,

So it's kind of nature's way of telling you to leave,

and that's obviously what the little auks are doing.

And us, too!