Europe's New Wild

- Europe... a continent renowned for its spectacular cities

and civilizations.

But this is a surprisingly wild land,

with over 10 million square kilometers

of diverse natural habitat...

stretching from the northernmost reaches of the Arctic...

to the crystal-clear waters of the Mediterranean Sea.

And across this extraordinary continent,

an epic transformation is under way...

as the wild heart of Europe is unleashed once more.

People are supporting the natural world.

- Let's go to the nest and see how the chick is.

Species are being reintroduced.

- He's not sleeping very well, so we have to be really fast.

- And nature itself is bouncing back.

The circle of life is being reforged...

as the wild returns to Europe.

In the Carpathian Mountains,

a wildlife reintroduction

is transforming the land

and making Europe's untamed heart

even wilder.

- In the east of Europe lies a wild paradise...

a rugged forest

where dense foliage camouflages and protects...

one of the most elusive cats on the continent...

...the Eurasian lynx.

The largest of the four lynx species,

this secretive wild cat thrives here.

It's the perfect place to raise cubs...

like these little fellows,

who are completely dependent on Mom.

She tries to clean them,

but they have other ideas.

At 2 months old, they just want to play and explore.

If they wander off...

...Mom is never far behind.

She'll take care of them for the next 8 months...

...until they learn to hunt on their own.

Then they'll leave her and find their own territories,

starting new lives as solitary predators.

There's around 10,000 Eurasian lynx living in Europe...

and a quarter of them live here...

in the Carpathian Mountains.

The Carpathians are a stronghold for the lynx

and many other species.

Here, a wide range of wildlife

thrives on rugged landscapes...

...and in pristine water.

The Carpathians span over 1,500 kilometers...

and run through eight separate countries.

For centuries, they've been a refuge

for Europe's most iconic species.

Predators...

...and prey animals...

large and small...

find refuge in this biodiversity hotspot.

But one of the ecosystem's most important creatures...

...did not find protection here.

The European Bison.

It's the continent's largest land mammal,

standing almost 2 meters tall

and weighing almost as much as a car.

Today, it's rarer than the white rhino.

But once, the species used to roam all across Europe.

Until the end of the World War I...

...when due to hunting and habitat loss,

not a single bison was left in the wild.

Out of the few individuals that survived in captivity,

12 were carefully bred

in order to keep the gene line going.

Today their descendants, captive and wild, number 7,000.

Bison are a key species with the power to shape the landscape.

A single male can eat over 30 kilos of plants

and grasses in a day...

which transforms overgrown land

to a patchwork of meadow and forest.

And they love getting down and dirty.

By rolling in the sand to get rid of parasites,

they clear the ground

for smaller animals and insects.

Thanks to human intervention,

European bison are slowly recovering.

Here at the Tierpark Berlin,

a team of specialists is working closely

with the conservation groups Rewilding Europe and WWF.

Their joint mission...

reintroduce bison to the Carpathians

after more than 200 years of absence

and help restore Europe's ecosystem.

It's an intensive breeding program.

Each animal is carefully selected.

Over the last five years, more than 50 bison

have been released into the mountains of Romania.

Today, after months of preparation,

five more are ready to join them.

They're an independent herd,

headed by a matriarch called Tirunesh.

- Tirunesh is a good leading female.

She is strong. She know what she's doing.

So she will hopefully lead the younger group

through the first winter.

- First, the bison need to be loaded into individual crates...

...which is easier said than done.

The keepers are trying to stay out of sight.

But to convince some of the younger bison...

now they have to get creative.

Even a juvenile could cause a fatal injury with its horns.

But eventually, the bison is moved safely into the crate.

These young bison have no idea

of the scale of the mission that lies ahead.

They face a 1,300-kilometer journey

through the heart of Europe.

It takes two days on the road

for the bison to finally reach their new home...

The Carpathian Mountains.

Now they're set to join 18 others

in a bid to ignite a new era...

for this gentle giant of the animal kingdom.

Matriarch Tirunesh and her four companions

have never been free before.

Now with over 60 bison roaming the Carpathians,

nature can take advantage of their presence

in all kinds of ways.

Animals can thrive where bison graze and wallow.

New plants grow in freshly grazed land.

Insects, birds, mammals, and reptiles

all benefit from the bison's return.

Even their hoof prints come in handy.

Filled up with rain water,

it becomes a welcome pit stop for an adventurer...

on an epic journey.

This female yellow-bellied toad

may have to travel almost 200 meters

in search of a pond to lay her eggs.

The water-filled hoof print lets her soak up oxygen

through her huge pores, allowing her to breathe.

But she must continue her journey.

And when you're just 5 centimeters tall,

it's a long road.

She's lucky.

There's another perfect puddle just around the corner...

providing a little relaxation for the toad in the hole.

The hoof print pools warm up quickly in the sunlight,

creating a warming bath for this cold-blooded creature.

With one last push...

...she finally reaches the perfect pond.

But she's got company...

dozens of males looking for love.

It's unlikely this female would ever have made it

to this mating pond

without the help of the water-filled bison tracks...

making the bison an improbable Cupid in this toad romance.

With the change of seasons,

these mega herbivores bring new opportunities

to the Carpathian's residents.

When the mountains become blanketed in thick snow...

predators have to work harder.

In Romania's Carpathians,

this red fox is looking for a meal.

But he's not relying on his eyes.

Instead, he uses his excellent sense of smell...

and hearing...

to locate a suitable snack.

The fox can detect and stalk a rodent under the snow

from around 30 meters away.

And when it pounces, it uses its tail like a rudder,

to balance in midair.

Success.

Foxes aren't the only ones looking for food in winter.

Bison continue to graze

on grasses hidden beneath the snow.

But they also rely on small trees and branches

to make it through.

As they continue to graze the forest,

all this eating creates open areas...

and makes room for one of the most unusual mating rituals

to take place.

Dawn in Europe's pine forest,

and time for the headliner to make an appearance...

a male capercaillie looking for love.

To attract attention, he calls continuously

and fans his tail feathers.

He's chosen this clearing for its good acoustics

and visibility.

And it works.

The female is transfixed.

But there's competition.

Another male arrives, and things quickly turn serious.

He's prepared to fight.

At first, it's just a lot of noise.

But then things get physical.

The two warriors can't lose focus.

One false move could lead to injury...

or even death.

They face off...

until one concedes defeat.

And the winner gets what he came for.

Or maybe not.

In the depths of winter, the return of bison