Winter's Fortress | The Alps

♪♪ NARRATOR: These lofty peaks are among the most revered in history.

Their very name defines every mountain habitat the world over -- Alpine forest, Alpine lakes, Alpine tundra.

They are a battle They are a bad of ice against rock, wind against water, winter against summer.

♪♪ And yet, remarkable mountaineers thrive here, busy with battles of their own... ...while others are slowly returning to reclaim their place.

All must seize the high life of summer before these peaks become winter's fortress.

Soar into the Alps, a realm of white brightness... ...and thunder.

[ Rumbling ] ♪♪ ♪♪ ♪♪ NARRATOR: A thousand peaks crowning a continent -- The Alps.

Between sea and summits, a trove of natural treasures -- Alpine grasslands... Arctic tundra... Mediterranean gardens... gigantic glaciers... [ Squawking ] ...gaping canyons echoing the sound of thundering waters... ...dark woodlands full of mystery... [ Clucks ] ...barren crags... and slopes of vivid green.

A raw expanse to overwhelm the eye of all but one -- the one who soars above it all.

♪♪ ♪♪ ♪♪ ♪♪ [ Eagle shrieks ] It takes an eagle's eye to appreciate the Alps, their majesty and their dimensions.

[ Wind rushing ] This is the realm of the golden eagle.

In Alpine lore, the realm of winter.

♪♪ Arching across some 600 miles, this crumple zone between converging plates rises steadily from eastern lowlands to Europe's highest pinnacle.

Major rivers rising on the roof of Europe, often separated by narrow watersheds, reach three different seas.

Eight nations share the Alps -- three of them, their highest mountain.

Monumental towers guard the King of the Alps.

Dwarfing Europe's ancient fortresses, this martial architecture bears witness to an age-old battle -- the elements against a rising mass of rock.

♪♪ These ramparts are granite, the rock that sets this mountain apart from the rest of the Alps.

Looking east from its top, a skyline of majestic, yet lesser peaks.

To the west, nothing but big skies.

♪♪ Mont Blanc -- the ancient patriarch of the Alps, the highest point.

Other parts of the Alps were thrust together from far and wide -- stacked, folded, and jumbled in the vise of colliding continents.

But these granites rose straight from the deep, and they are still rising.

It may seem strange, but glaciers accelerate their rise.

In high valleys, the snowfall of millennia accumulates.

Snow turns into solid ice, but solid is not rigid.

Ice under pressure begins to flow downhill.

[ Ice crackling ] As the valley widens and the ice flows over edges, it's stretched and torn.

♪♪ [ Water trickling ] At the height of summer, once the blanket of snow is gone, the sun can reach deep down.

For decades, summers have been getting hotter, with a new record nearly every year.

Today, glaciers are melting.

But for eons, the scraping, scouring, plucking, and polishing action of massive ice flows, many times mightier than those we see today, have worn down the Alps.

Thousands of feet of rock have been removed -- an enormous weight loss enabling the Alps to rise.

♪♪ Below the glaciers and above the treeline, sprawling grasslands are the summer resort of red deer.

[ Deer calls ] But the summer is gone, and the rut is all but over.

[ Calling ] The stags are totally exhausted, worn-out and bruised like warriors returning from combat.

And combat it truly was.

Many hinds have gathered on this rutting ground and attracted many stags.

♪♪ ♪♪ Where strong stags compete for females, there are battles.

♪♪ ♪♪ For dominant stags defending a harem, that means relentless stress.

♪♪ ♪♪ [ Deer calling ] After two weeks of total exertion, the stags stay on for a few more quiet weeks to heal their wounds and regain strength to face the winter.

♪♪ [ Deer calls ] ♪♪ Clear frosty nights and frigid morning mists mark the change of the season.

In the skies, the tide has turned.

[ Wind whistling ] From now on, the northerlies prevail.

♪♪ Returning from a reconnaissance flight, the eagle has seen all he needs to know.

♪♪ A marmot den is something an eagle will remember, even until next spring.

♪♪ Marmots are twice as fat now as in the spring, unlike stags, who've just lost one-fifth of their body mass.

For half a year, these Alpine rodents have stuffed themselves.

[ Marmot chirping ] Now it's time to make the den cozy for a long winter underground.

To hold out six months underground, you want a comfy home.

♪♪ In this den, the male prepares the bedding.

His mate supplies the hay.

Out there, it's risky.

But as long as the choughs are watching, one can relax.

♪♪ ♪♪ A safe, well-furnished den is a marmot's dream.

But it's not quite there yet.

More padding is wanted.

[ Chittering ] Even when the bed's perfect, with a restless bedfellow, a good rest is hard to get.

♪♪ ♪♪ Marmots have to stay put all winter... ...while the choughs can escape to a milder sphere.

♪♪ Way below, at the foot of the mountain, autumn still has a few short but sunny days in store before winter arrives.

♪♪ Magically, overnight, maples and larches have turned to gold.

♪♪ Rooted in the sediments of an ancient ocean, vertical forests now shine in the brightest hues.

But soon, the scenery will be monochrome.

♪♪ ♪♪ In hidden valleys of the southern Alps, a revenant has been secretly about for a few decades now.

The Slovenian, Italian, and Austrian Alps have seen the cautious, gradual return of an old native who had been missing from almost the entire mountain range for a century.

A brown bear mother and her nearly grown-up cubs, feeding on beechnuts.

They're getting ready to hibernate in a well-hidden cave -- maybe together for one last winter.

When ravens appear, it may be taken for a sign.

[ Bear panting ] Alerted, one of the youngsters tests the wind.

The mother lets him take the lead -- a teaching moment.

That's what the ravens meant.

A stag, gored in the rut -- something the cubs have never seen before.

Warily, they explore.

[ Bears vocalizing ] But then, they really go at it.

Every extra pound on their ribs will help to get over the winter.

This might be the family's last shared meal before they go their separate ways.

[ Bear calling ] Ravens -- early birds at any carcass, but they need big predators to carve it up.

It's best to wait a while.

These wise birds know -- first come, first served is not a natural right.

♪♪ The wind is getting colder, sharper.

♪♪ ♪♪ A thousand mountain streams have fallen silent.

♪♪ Warm hues of fall belie the coming cold.

Glowing in the sunset, the cold rocks of these famous peaks conjure up memories of a distant, much warmer past.

♪♪ A young eagle in search of a territory of his own explores the Southern Limestone Alps stretching across Slovenia, Austria, and Italy.

The limestone of Italy's Dolomites has nothing in common with the granites of Mont Blanc.

The Dolomites are only half as high, yet their breathtaking panoramas can vie with any icon of the Alps.

Erosion grinds its sculptures down to what they once were -- sand and silt in a warm, shallow sea.

♪♪ Layer by layer, over more than 200 million years, skeletons of marine organisms accumulated enormous bodies of sediment on the ocean floor.

Africa's collision with Europe pressed them up into the sky.

Thus a tropical seafloor became the habitat of an ice-age remnant.

♪♪ Arctic or mountain hares once inhabited the cold plains of ice-age Europe.

When the climate turned warm, they retreated northward to the Arctic and up to the higher regions of the Alps.

Scandinavian and Alpine populations are now 1,200 miles apart.

Adapting their camouflage, mountain hares change their fur twice a year.

A few more weeks, and their winter coats will be as white as snow.

♪♪ Meanwhile, it's best to stay alert and near hiding places.

With marmots already underground, the eagle has set his sights on hares.

An eagle's eye works like a powerful zoom lens.

He can spot his prey long before it can spot him.

♪♪ ♪♪ ♪♪ ♪♪ A bungled stealth attack.

This eagle is still a rookie.

♪♪ A majestic rookie, by any means.

♪♪ The low sun dazzles the eyes.

But the moment it's hidden, the cold breath of the mountains makes the body shiver.

♪♪ Those who remain up high and out in the open must be well-prepared for harsh days ahead.

Down in the valleys below the fog, it's now often colder than on the high slopes.

Soon the bears will have disappeared into their winter dens.

Deer descend to their winter quarters in the forest.

♪♪ Long before the first snowfall, winter sends its harbingers.

♪♪ [ Wind whistling ] ♪♪ Each night now, the temperature plummets below freezing.

♪♪ The mirrors of a thousand mountain lakes will soon go blind.

[ Ice crackling ] ♪♪ Up among the crags, the snow is here to stay, setting the stage for a breathtaking spectacle.

Chamois don't fear the cold.

Quite the opposite -- after languishing in humid summer heat, they are now in their element.

On high slopes and crests, the wind will sweep away the snow so that the chamois can find grazing even in winter.

♪♪ One who has prudently prepared for a long winter is the spotted nutcracker, having stashed thousands of pine seeds in hundreds of deposits in the ground along the timberline.

The challenge is to find these larders under the snow.

This takes nearly magic memory.

His bird brain has stored a precise topographical map... ...a 3-D map of a vast and complex terrain, which looks very different now than it did in autumn.

Sometimes the ground is frozen so hard that the nutcracker cannot get all the seeds he has buried.

These seeds will sprout in spring, thus the flying forester rejuvenates the stock of pines from which his own species will profit for centuries to come.

♪♪ ♪♪ Among the chamois, the mood is tense.

Bucks and females are now coming together.

It's all about the future of their population.

Bucks spray their coats with sperm and urine -- personal perfume any female will remember.

A secretion from glands at the base of a buck's horns marks his claim near the female's stamping ground.

♪♪ Rivaling bucks tax each other.

♪♪ Each buck needs to decide -- attack or retreat?

♪♪ ♪♪ Counterattack or exhaust the opponent?

Anything but surrender.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ A performance, and a stage, to take one's breath away.

♪♪ ♪♪ This is the sovereign airspace of a pair of golden eagles.

♪♪ ♪♪ Over the years, they've built a number of nests around here.

They do not breed each year, but soon, there will be two eggs in one of the nests.

Across the Alps, well over 1,000 breeding pairs are occupying all the suitable territories.

Breeding success greatly depends on how well a pair gets through the winter.

♪♪ Golden eagles stay together for life -- for three decades and more.

♪♪ ♪♪ ♪♪ [ Wind rushing ] Being born up here means being born to climb and to flourish in arctic conditions.

[ Wind whistling ] Each morning, the females scramble up to the ridges where the wind has cleared away the snow and they can feed.

The bucks follow.

It's not an easy climb.

A film of frozen fog covers these limestone rocks in the southern Alps.

This is dangerous terrain.

[ Rocks clattering ] In early winter, bucks become obtrusive stalkers.

Every move she makes, every step she takes, a buck will be watching.

There's no liquid water up here, yet ibex stay up high all winter.

A gang of young bucks has closed in on a female leading a kid.

With their tongues and a special organ on their gums, they taste the scent she emits, which signals her readiness to mate.

♪♪ ♪♪ She's the focus of attention, but indifferent to these youngsters.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To be taken seriously as a suitor, a buck must be at least 6 years old, but it's rare that bucks under 9 or 10 years get to mate.

Two mature, strong bucks have been standing back and watching.

One of these, she might choose.

[ Horns knocking ] But the choice is often made by fate.

[ Horns knocking ] ♪♪ He's out of the race... for good.

A broken leg up here means death.

♪♪ Fate and the weather turn quickly in the Alps.

Within an hour, a calm and sunny day can turn into a howling white inferno.

A humid southerly from the Mediterranean hitting the high ridges can bring gale-force winds and masses of snow.

♪♪ In an airborne life, whims of the atmosphere are not the only challenge.

Bearded vultures, giants of the sky, are claiming their share of space.

♪♪ ♪♪ To avoid nasty weather from any direction, ibex and chamois try to be in the right place at the right time.

[ Wind howling ] Mountain hares let the wind work for them, exploiting snow drifts for shelter.

In the same way, ptarmigans will calmly sit out any storm for days.

Not even an eagle can see them now.

For the golden eagle -- neither an arctic nor a high-mountain species -- these are hard times.

[ Wind howling ] Six feet under is the perfect place to truly rest in peace.

Marmots cozy up as families to keep warm.

The temperature inside the den decreases gradually from 60 degrees in autumn to freezing in spring.

The animals also lower their body temperature down to about 40 degrees plus.

They survive on their body's storage of fat and water.

♪♪ With thick layers of snow and soil on top, the entrance to their extensive den securely blocked, the marmot is nature's paragon of bunker mentality.

There's not the slightest draft down here, no matter how hard the storm may blow outside.

♪♪ In such weather, the zone above the treeline is a hostile place.

Roe deer and red deer are seeking shelter in the mountain forest.

[ Wolf howls ] But more and more often in recent years, they are not alone here.

♪♪ Wolves had almost become extinct in the Alps by the early 20th century.

About a century later, their tracks in the snow appeared again.

♪♪ For thousands of years, red deer would migrate from the high Alps down to the floodplains of big rivers.

But their migration routes are now cut off by roads and towns, so they stay in the mountain forest.

Covered in water-repellent top hair over a fluffy layer of wool, they can deal with the cold.

It's the deep snow that wears them down and the lack of forage forcing them to subsist on a meager diet of bark and branches.

Their bodies are now in energy-conservation mode.

In this state, having to flee from a threat will critically tax their reserves.

♪♪ For fast-flowing mountain rivers to freeze over, temperatures must drop further... and they will.

The deer limit their movements to trampled paths between resting and feeding areas and nearby drinking places.

In contrast to deer, a wolf's energy level stays high.

Blood circulation never slows.

Being much lighter than deer, wolves do not sink into deep snow as easily.

After generations without wolves, bears, and lynx in the Alps, deer are beginning to learn again about big predators.

For a deer, the extra stress of a chase lowers the chances of surviving the winter.

Remote valleys of the Alps have been abandoned by people in recent decades.

Fortunate for red deer, the new wilderness offers alternative prey.

♪♪ ♪♪ ♪♪ One particular species has invited back the wolf.

♪♪ ♪♪ ♪♪ A burly wild boar would be too risky a quarry for a single wolf.

But as a team, the pack is confident it can take on a single animal.

♪♪ ♪♪ ♪♪ Poor judgement.

This individual seems rather powerful.

Better to let it go.

♪♪ ♪♪ But somewhere, there's always a ready meal.

Worn out by the rut, the trials of winter have proved too much for an old stag.

♪♪ Winter is a hostile season.

Up among the peaks, it never really ends.

The monumental Matterhorn and the massive Mont Blanc have featured as the thrones of winter in ancient Alpine lore.

♪♪ ♪♪ No matter how often the sun has risen during past millennia, so far it's never thawed away the snow on these iconic summits, never stripped them of their mantle of majesty.

However stunning the snow-capped Alps may appear from distant lowlands, to fully appreciate their glory, their vastness, and complexity, one must ride the winds like an eagle.

♪♪ But the face of the Alps is changing.

A thick new layer of fresh winter snow veils the rapid melt of what used to be called "the eternal ice."

Over eons, at a glacial pace, ice has been grinding down the rocks.

Now a warming climate bears down on the glaciers.

In their rapid demise, winter is just a minor break.

♪♪ ♪♪ Even the harshest winter has its balmy days.

The storm is over.

But other risks persist.

♪♪ Ptarmigans and hares are now replacing marmots on the eagle's menu.

♪♪ But the little animals in their winter suits are lucky.

The eagle is distracted.

A huge bearded vulture allows no stranger near his nest.

♪♪ ♪♪ Ignoring the sky, the youngsters are caught up in a play-fight.

♪♪ In the eastern Alps, tracks in the fresh snow are evidence of chamois on their way back up to the high ridges.

♪♪ The forest offered shelter from the wind, but little food.

♪♪ The snow now lies deep.

♪♪ It's only on windswept hilltops where some grazing might be found.

♪♪ After a blizzard, the steep lee side of a mountain can turn into a hazard zone.

♪♪ ♪♪ The wind -- the architect of avalanches -- has moved enormous volumes of snow.

Along the edges, it has piled up huge drifts.

Tons and tons of wind-pressed snow projecting from sheer cliffs are a threat to every living thing below.

♪♪ Impossible to say when the spell will break.

♪♪ ♪♪ [ Rumbling ] The speed and force of the white death is beyond comprehension.

[ Rumbling continues ] Heart-stopping violence fades into peaceful silence.

♪♪ ♪♪ ♪♪ A new sunrise -- an expression of nature's indifference.

♪♪ The misfortune of some is fortunate for others.

[ Ravens cawing ] Ravens, as always, the first to descend on a funeral feast.

[ Ravens squabbling ] A frozen chamois is not exactly fast food, yet the ravens must be quick before the sovereign claims his own.

♪♪ ♪♪ ♪♪ Both ravens and eagles depend on avalanche victims to make it through the winter and get ready for an early breeding season.

♪♪ "Cleanliness is next to godliness," the old saying goes.

And why not mix in a little playfulness?

♪♪ ♪♪ When dense fogs fill the valleys, they give a vague impression of an ice-age panorama of the Alps some 20,000 years ago.

♪♪ Back then, only the highest peaks would protrude from the ice, such as the Grossglockner, Austria's highest mountain.

It's been the ice ages that sculpted the rising Alps and ground them down to their present size.

♪♪ Where the ice has vanished, grassland and woodland has conquered the ground, inviting new inhabitants.

♪♪ Europe's biggest cat.

The Eurasian lynx is another revenant to the Alps, after a century of absence.

The lynx is an elusive, solitary hunter.

♪♪ Roe deer, abundant in Alpine forests, are his preferred prey.

♪♪ Like most cats, the lynx hunts by surprise, not chase.

♪♪ Between hunter and hunted, it's a battle of the senses.

♪♪ Both animals pick up the slightest sound, the smallest movement.

♪♪ Cats can move noiselessly, like ghosts.

♪♪ ♪♪ Success depends on getting close enough for a surprise attack.

♪♪ ♪♪ ♪♪ The frustration is shared.

[ Lynx panting ] The waters are beginning to flow again.

The ice is gone.

Warm winds set off the snowmelt.

♪♪ ♪♪ Even under the snow, the marmot's inner clock is right on time.

♪♪ There's nothing in these mountains that would escape an eagle's eye.

♪♪ High up, on a tiny ledge, two delicate new lives have just begun.

♪♪ As spring cascades towards another Alpine summer, thousands of parents will again raise the next generation of wildlife in the Alps.

[ Cooing ] ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.

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