All language subtitles for BBC - Yellowstone 2. Summer [2009 1080p x264 DTS-1510]

For six months Yellowstone
endures an unrelenting winter.

An ice world of hunters.

And hunted.

But now footsteps on
the slopes of a mountain ...

herald a change in the season.

The sun regains its strength.

Water flows again.

The race begins to recover
winter's losses.

To play.

Learn.

And breed.

But the summer ahead
will be fleeting ...

and far from easy ...

in this unpredictable wilderness.

It's April.

The land lies exhausted by winter.

Everything is waiting for the
return of the sun's warmth.

The end of winter comes late ...

to the mountainous northwest
of the United States.

And in particular,
it lingers in Yellowstone.

The heart of Yellowstone is
a high, cold plateau ...

8,000 feet up, surrounded by the
spires of the Rocky Mountains.

After five months sleeping
in those mountains,

a powerful presence returns.

This female grizzly bear ...

has awoken early to find food
for her two-year-old cubs.

But she may have brought
her family here too early.

The Tetons,

on the extreme southern edge
of the Yellowstone plateau.

It's where the spring thaw
normally begins.

But this year it's come late.

Deep snow is still a novelty
for her cubs.

But she is much more focused.

Led by her nose,
she risks her 300-pound bulk ...

on the thin ice of a bend
in the Snake River.

It doesn't look promising ...

but her cubs follow
with only a little hesitation.

With paws that can
knock down an elk,

she feels delicately in the water.

A fish frozen beneath the ice
by this cold winter.

One fish won't feed the family ...

but she knows there are
almost certainly more.

The cubs must learn to find them.

A little success
for one of the cubs.

This mother bear's experience ...

gives her family a good chance
of survival until spring arrives.

They will return again and again
as the thaw releases more fish.

On the warmer plains and valleys
that surround the plateau ...

grazers are on the move.

They left the high country
to avoid the worst of the winter,

and now begin the long journey
towards the heart of Yellowstone ...

in time for summer.

These elk are led
by experienced adults ...

who have made this trip
many times before.

They are followed on their migration by
the most ancient of American grazers.

Pronghorn.

Though predators may follow,
none can outpace them.

Over distance, these are
the fastest animals in the world,

taking a long migration
in their stride.

Migrating elk and pronghorn
must follow the advancing thaw.

But higher up in the valleys
one animal is well ahead of them.

Bison are adapted for cold.

These herds need to be
in Yellowstone early ...

to have time to bring up their
young in the short summer ahead.

Calves born during the journey
will be tested.

Clues to why the herds are drawn
to the Yellowstone plateau ...

lie in its deep and unique history.

This plateau is the cratered bowl
of a huge sleeping volcano ...

and molten rock below the surface
still pushes the land up ...

to the cold of high altitude.

But it has not been the only force
to shape the land.

Millennia ago the volcano
was covered by an ice sheet ...

thousands of feet deep.

The few glaciers that border Yellowstone
are an echo of a time ...

when ice scoured
and smoothed the entire plateau.

When these great
ice sheets retreated,

they left pulverised rocks
in their wake,

the foundation for fertile soil ...

and some of the richest
natural grasslands in America.

But in May this year,

in the heart of Yellowstone, that
grass is still beneath thick snow.

Something this ground squirrel
was clearly not expecting.

But as the sun's strength returns,

spring bulbs start to push through
the late snow.

At last a sign
that winter is losing its grip.

Bluebirds, too delicate to survive
deep winter here,

now return to take advantage of
the first hatch of stoneflies ...

from a thawing river.

As six months of snow and ice
begins to melt,

Yellowstone starts
to come back to life.

Cascading snowmelt swells
the streams and rivers.

It's a hazard that
the migrating herds must cross.

Young are barely up to the task.

The Yellowstone River has
increased its flow tenfold.

In less than two weeks ...

the thaw has brought a remarkable
change to the heart of Yellowstone.

As the migrating herds arrive
in the plateau's river valleys,

the spring is here.

This is why they
have made the journey.

After the famine of winter,

food is everywhere.

Birds have flown in from as far away
as the Arctic and subtropics.

Canada geese join flocks of
white pelicans to breed here.

A snow-covered wasteland
is transformed ...

to an American Serengeti.

But it's a landscape like no other.

Geysers made Yellowstone famous.

Yellowstone sits above the
molten core of a volcano.

Underground water becomes super-heated
and erupts into the air.

Strangely, geysers and hot springs
can creep around the landscape.

The curious shapes of Grotto
Geyser are actually trees,

entombed and petrified
by minerals dissolved in the water.

Hot water scorches and drowns the roots
of trees encroaching on the valleys.

It can keep the forests in check
and the rich pastures open.

Those pastures now produce the new
grass needed to make rich milk ...

and feed a bison baby boom.

The few calves born
on the migration ...

are now joined by hundreds
of new youngsters.

The predators have been
waiting for this.

Coyotes have a voracious
reputation here,

but on its own this one is certainly no
match for a healthy bison and her calf.

Pronghorn give birth to twins,

each carefully cleaned
to hide their smell from predators.

While they are with her
they are relatively safe ...

and for now the coyote is content
with the afterbirth.

But the mother pronghorn must leave
her calves alone while she grazes ...

and with legs as wobbly as stilts,

their best defence is to lie low.

She has young of her own to worry
about, a demanding litter of nine,

whose arrival has been carefully timed
to coincide with an abundance of food.

But they are not top dog here.

Yellowstone's top predator, the wolf,

dominated during the winter
but is far less visible in summer.

They prefer to stay close
to well-hidden dens ...

to protect their pups
from rival packs.

This pack seem prepared to
allow their young a brief foray ...

to experience the world
beyond their den.

Even in Yellowstone ...

it is extremely rare
to see wolf pups like this.

Before long they are summoned
back into the forest by the pack.

It will be winter before
they are regularly seen again.

As May turns to June,

Yellowstone sees its nursery season.

By early June summer is finally here.

In the flower meadows ...

plants turn sunlight
into the sugar of nectar,

and that's what Yellowstone's smallest
migrating bird has been waiting for.

The Calliope hummingbird has made
the journey all the way from Mexico.

He'll make this
flower patch his own ...

and he'll fight to defend it.

He'll even take on a far larger
Rufous hummingbird.

But his high-octane lifestyle
critically depends on the summer sun,

and in Yellowstone
that's never guaranteed.

In the mountains surrounding the
plateau, summer has not yet arrived.

At this altitude
it is still bitterly cold.

These mountains barricade
Yellowstone in a ring of ice.

And if the sun is
swallowed by cloud,

the cold can drive down
from the mountains ...

bringing with it
a punishing echo of winter.

It can snow in any
month in Yellowstone.

The warm nursery meadows
of a few days before ...

are now buried by a June blizzard.

A curtain of snow dulls senses.

This mother grizzly bear
must now be especially careful.

A male grizzly will often
kill cubs if he finds them.

And though she would rather
sit out the storm, she must move.

Panicky cubs could easily
be lost in a blizzard.

As soon as she feels it is safe,

she settles to suckle
and reassure them.

Bison can shrug off
this sudden change in the weather.

They are, after all, built to
survive a Yellowstone winter.

But this tiny hummingbird
is more vulnerable.

Flowers damaged by snow will die ...

and the nectar the hummingbird
needs goes with them.

Hummingbirds must be resourceful
to survive.

Bark wells dug by a sapsucker,
a type of woodpecker,

quickly fill with sugar-rich sap
as soon as the warm weather returns.

A little pilfering provides this
hummingbird with the energy it needs ...

until the new flower buds open.

Summer moves quickly.

By late June the blizzards of a few
weeks before seem a distant memory.

At last the summer is
well-enough established ...

for this hummingbird to take the
plunge and raise a brood.

The living is easy.

But it won't last long.

At this altitude
the air is so dry ...

that rain evaporates
before it even hits the ground.

The water that flows off the plateau
is no longer being replaced.

Already there is drought in
forests beyond the meadows.

Yellowstone has vast
ancient lava fields.

This porous volcanic rock
holds onto very little water.

It is dominated by lodgepole pine,

a tree that can cope with
the arid conditions.

The forest may be parched,

but there is still water here
in lakes formed by ancient glaciers.

A visiting male otter
woos a female on the lake's shore.

But she seems a little distracted.

Her two pups are nearby.

They're about 10 weeks old ...

and the time is right to lead them
from the holt.

Males are not above
stealing food from cubs,

so she makes it very clear that
he is not going to be joining them.

This female grew up on the lake,

so she knows where to take the cubs
for a very special trip.

Yellowstone cutthroat trout,

amassing in the mouth of a stream
that feeds the lake.

They're preparing for
their annual spawning.

But the trout must wait.

The stream is still running fast,

too turbulent to lay their eggs.

It's a nervous time for them,
and for good reason.

This osprey has a brood to feed
and will be back.

Now the otters are here, too.

She chooses her moment
to lead the pups upstream.

Then leaves them to watch ...

and gives them a lesson in hunting.

A large trout like this full
of eggs is a trophy catch.

She chews its tail first to make
sure the fish can't get away.

While the pups are
still demanding milk,

the mother otter will often keep
the whole fish for herself.

Her pups are happy enough with caviar.

As the flow becomes slow enough
for the trout to lay eggs,

there is a brief window of
opportunity to spawn ...

before the river gets too shallow
to swim upstream.

The female digs a trough with
sinuous flicks of her body ...

and the attending male fertilises
the eggs as they are laid.

Millions of new lives.

It's now early July,

and what looks like more snow ...

is actually a blizzard
of seeds and insects.

There is more life in the park now
than at any other time of the year.

It's a turning point in the summer.

Through the coming month
the days will get hotter and drier.

The plants will grow
less vigorously ...

and the pace of summer will slow.

The meadows are not so welcoming now.

The grass becomes less nourishing ...

as it puts its energy
into seeds and roots.

Bison lose the last of
their winter coats.

In the heat, tempers fray.

To escape soaring
ground temperatures,

cowbirds choose a bison's back
as a cool place to feed ...

and catch the breeze.

Biting insects now become
a draining nuisance.

A grizzly bear escapes
the heat and bugs ...

in the cool waters of a lake.

As the ground dries,

bears find little food to eat
out on the Yellowstone plateau.

There is less to graze
and digging roots is hard work,

so they start to head to
the cooler mountains beyond.

In the mountains,

glacier lilies that finished flowering
a month before on the plateau ...

are only just coming into bloom.

Up here, where spring
has only just arrived,

bears can find food again.

As the thaw reaches up
into the mountains,

a part of Yellowstone that few
ever see is briefly revealed.

From its first day above the snow,

this pika is obsessed by food.

It's in a frantic race to restock
its winter larder ...

before the snow closes in again.

They're a part of a community
of small mammals ...

which live life
on the edge up here.

Carefully chosen plants are harvested
and dried in haystacks ...

before being stored below ground.

This larder must be over 50 times
the pika's bodyweight ...

to get it through winter.

The summer is so short up here ...

that few animals can
permanently live any higher.

But higher is exactly where
the bears are heading,

above the tree line ...

towards the barren rocks
of the peaks beyond.

It seems an unlikely journey
for an animal led by its stomach.

Why they do this
will only become apparent ...

as the summer draws to its close.

Meanwhile, 2,000 feet below them
on the Yellowstone plateau ...

the grasslands are facing drought.

Bison calves are more independent
of their mothers.

The adults' focus is now set
on a ruthless competition to mate.

A male bids to enter a herd
with females in season.

He uses dust to accentuate
all his size and power.

Another male already established
in the herd ...

answers the display.

And waits.

The newcomer responds by scent
marking and moving even closer.

This challenge cannot be tolerated.

The resident male has won.

Having seen off his rival,

next summer's calves
will likely be his.

Victory in the dust of high summer.

But now there is a larger challenge
to the whole of Yellowstone.

These clouds don't signal rain.

They are vast smoke plumes.

Yellowstone is burning.

Throughout the summer,

the dry lodgepole pines have
become like a tinder box ...

and lightning has struck the match.

The worst wild fires
will burn for weeks.

In 1988, a third of Yellowstone
burnt in a single summer.

Devastation.

Animals that depend on these
forests will starve this winter.

But Yellowstone itself has
a longer perspective.

Ashes fertilise the soil
and fire opens it up to sunlight.

As the forests regenerate,

new life finds opportunity.

In August, fledgling hummingbirds
gorge in fields of fireweed ...

that have risen
from the forest's ashes.

For them the summer
is already nearly over.

They must chase the sun south
before winter returns.

But just as the first of Yellowstone's
new generation are preparing to leave,

its last visitors are arriving.

Night after night,

army cutworm moths have been escaping
the heat of a distant prairie.

They have been flying in
on favourable winds,

hiding away in rock crevices
in the mountains.

This is why the grizzly bears
climb to the barren peaks.

Two miles up they begin
to search for the moths.

It's the end of summer ...

and the last snow of winter
holds on only here.

It offers a few refreshing mouthfuls
for travel-weary cubs.

Many of these bears learnt about
this site from their mothers ...

as a part of local bear tradition.

The family sets to work finding
moths, digging into the loose rock.

Though each moth is very small,

a bear that makes
a successful strike ...

can harvest up to 40,000
in a single day.

That's 20,000 calories and
vital weight gained for winter.

Having spent all
summer avoiding males,

the mother now finds one
much too close for comfort.

Perhaps he's seeking a mate,
but he is unwelcome.

Leaving her cubs she confronts
the male head on.

As she approaches
to see him off again ...

she realises she has been injured.

A damaged jaw would be a disaster
for her and her family.

Clearly in pain,

she leads the anxious cubs to
high ground away from the male.

She nurses to calm
and reassure them.

The injury does not seem serious,

but she decides to lead her family
back down from the mountain.

This will be the last time
these cubs feed here as a family.

By next year they
will be independent,

ready to face their world alone.

Sun has briefly brought warmth
to Yellowstone,

long enough to fuel the raising
of new generations.

But just as summer reveals the full
extent of Yellowstone's diversity,

a curtain of winter ice
is set to descend again.

The days are getting shorter,

the sun losing its power.

Now there are just a few short
weeks to prepare for winter.

One final flourish of life ...

in Yellowstone's briefest
but most glorious season.

Autumn.