All language subtitles for 52F3031A19D1C7208F9F36B3C81657A8_eng

The Caledonian pinewoods
of the Scottish Highlands.

This patch in the Cairngorms
National Park is one of the oldest

remnants of this
ancient, wild wood.

It's the stage for an
equally ancient drama.

Woodland-dwelling golden eagles.

These birds are clearly
at home amongst the open,

old-growth forest.

Golden eagles once flew across
much of the uplands of Britain

and Ireland, but are now
absent from many areas

due to human persecution.

So, their huge, three-metre
nest on the edge of this

wood is now a rare sight.

The nest is home to two
fully-grown chicks...

..unusual for golden eagles,

whose stronger chick kills the
weaker in 80% of the nests.

Today, the chicks have only
been given a tiny weasel.

It could be a way of telling
them it's almost time to leave.

Only 1% of these native
pine forests are left,

so when the chicks do fledge,

their chances of finding a woodland
nest of their own are slim.

Ancient woodlands like these
are now rare and precious.

This magnificent oak is a
very special tree for me.

I've known it for over 70 years.

That may sound a long time,

but it's only about a tenth
of the life of this tree.

It's probably over
700 years old.

In England alone, we have more
ancient oaks than the whole

of the rest of
Europe put together.

But since I was born, we have lost
almost half of our ancient woodland,

and now we are one of the least
forested countries in Europe.

Woodland covers only 13%
of the British Isles,

and human influence can be
seen in every single bit of it.

But despite this, there's a
remarkable variety in the woodland

that remains.

Pines in the north...

..broadleaved woodlands
in the south...

..and even rainforests temperate
ones - along our western shores.

In this episode, we'll take
you on a seasonal journey,

to see how animals and plants
respond to the challenges of life

in our ever-changing woodlands.

Our journey starts here
in the Forest of Dean.

It's winter.

The low, weak sun
brings little warmth.

For some, this is
a time for slumber.

Hidden away, a tiny
dormouse is hibernating.

But not all the woodland residents
can sleep throughout the winter.

And one, in particular,
has a problem.

The robin.

With snow blanketing the ground,

the robin's favourite food -
earthworms - are out of reach.

Luckily, in this
forest, help is at hand.

Or rather, at snout!

Wild boar once roamed
woodlands right across Britain,

but they were pushed to
extinction by the 17th century.

Now they're back,

and although their return
hasn't been welcomed by all...

..for this robin,
they are invaluable.

The boar use their strong, sensitive
snouts to rip up the frozen ground.

This exposes worms - and
they are food for the robin.

It's the restoration of
an ancient relationship -

and probably the reason why robins
follow us around in the garden.

For them, a human with a spade
is just a pig on two legs.

As winter loosens its
grip - flowers emerge.

Snowdrops are first,

a sure sign that spring
is just around the corner.

Soon, more blooms appear,
each adding a little colour

to the dark forest floor...

..and inviting insects
to spread their pollen.

But while those on the ground take
centre stage - the trees above

put on a flower show
that is just as dramatic.

Willow catkins attract
insects in early spring...

..but small birds also visit,

feasting on the
protein-rich pollen.

Yellow smudges of it are carried on
their foreheads from tree to tree.

Willow trees are
either male or female,

and yews are like this, too.

This group in Sussex are some
of the oldest trees in Britain

and they have a different
technique to spread their pollen.

On warm days in spring...

..the flowers of
the male tree open

and release huge
clouds of pollen.

The quantities are so great

that the local fire brigade is
sometimes called out by reports

that the forest is burning.

As the pollen drifts away,

some of it may land
on a female yew

and, so, fertilise it.

THROAT CLICKS

In the Highlands of Scotland,

something else drifts
through the pine forests.

THROAT CLICKS

The voice of a
male capercaillie.

THROAT CLICKS

With only around 500 left in
these fragmented woodlands,

this is one of the rarest
birds in the British Isles.

It's mid-April, breeding season,

and this huge, turkey-sized male
is strutting around his arena.

In the trees above, a
female, or hen, has arrived.

THROAT CLICKS

The male, or cock,
will perform like this

for over six hours,
every morning.

THROAT CLICKS

GRUNTS

And it works.

GRUNTS

Several hens have gathered
around the prancing,

preening alpha male.

CLICKING AND GRUNTING

But with great success
comes great danger.

Until now, the other males
have kept well away...

..but powered by a stomach
full of pine needles,

a rival enters the arena.

THROAT CLICKING

He's almost a metre tall

and weighs over four kilos.

The two males size
each other up,

with a few preliminary pecks.

But with so many hens to
fight for - battle commences.

Contests like these can easily end
in broken bones - and even death.

The rival is starting
to lose face...

..literally. Some feathers have
been torn from around his head.

SQUAWKING

He senses defeat and retreats
from the alpha's territory.

GROWLS

CLICKS THROAT

Bruised and battered, his
time has not yet come...

..but at least he will
live to fight another day.

The alpha returns to
where the fight started,

tired but triumphant.

His reward is to mate
with all the females,

who will then pass on his
genes to the next generation.

The species as a whole,
however, is losing its battle

to survive in the
Scottish Highlands.

Capercaillie became extinct
in Britain once before,

back in the 18th century...

..and now a combination
of disturbance,

predation and
poor-quality habitat

is pushing these birds
to the brink once more.

BIRD SOUNDS

Soon these extraordinary sights
and sounds may disappear from

our woodlands -
for a second time.

In a deciduous woodland
just outside London,

the spring sun causes the
trees to burst into life.

On the forest
floor, a huge mound,

almost two metres high,
comes to life as well.

It's a nest of wood ants.

The ants may be tiny, but they are
well able to defend their home.

Should any would-be
predators approach,

they defend themselves and their
castle by squirting formic acid

into the air.

It's a brave bird, indeed,

that would take on this army.

Wood ants are
insatiable hunters.

They search the
forest floor for food,

swarming over
anything that moves

and dragging it
back to the nest.

It's thought that a
single colony may consume

over six million prey
items every year.

And not just on
the forest floor.

Up in the trees,
caterpillars have emerged

to take advantage of the newly
opened leaves of spring...

..so the ants take to the trees

Caterpillars may
look defenceless,

but they have several
ways of avoiding capture.

The first is to do nothing.

If they stay still, the
ants might march on by.

If detected, the second
option is to stand and fight.

Some caterpillars have a
surprisingly effective bite.

If that also fails, they resort
to their third and final option.

They attach a line of
silk to a leaf or stalk

and descend into space.

But this lifeline...

..can break.

But these wood ants don't
just prey on other species.

They farm them, too.

Aphids drill into the trees

to collect the sap that
is their only food...

..and they excrete a liquid waste
we call, somewhat flatteringly,

honeydew.

The ants collect it,

just as human farmers
collect milk from cows.

The honeydew is shared
throughout the colony...

..which may consume a quarter
of a tonne in a single year.

From hunting caterpillars
to milking aphids,

the ants have a huge impact
on the entire woodland.

It's a delicately
balanced system,

but the presence of the ants is
a sure sign of a healthy forest.

A quiet corner of an
ancient cemetery in Surrey.

It's late spring, and a female roe
deer is feeding on one of the oaks

that have taken root here.

She is on high alert.

Because with her,
amongst the graves,

is new life - her fawn.

Just a few days old

and at his most vulnerable.

Predators have also made a
home amongst the old graves.

A fox would make an
easy meal of a fawn.

While the youngster
suckles, he's safe.

A fox wouldn't dare take
on a fully grown deer.

But hiding silently
nearby is her second fawn.

Her speckled coat makes her less
obvious in the dappled light.

Once her brother has had his
fill, he goes off and hides...

..giving her a chance to feed.

Their mother keeps them apart

so that if one is caught,
the other might still escape.

Soon, they will both be too
big for a fox to be a danger,

but in times gone by,

wolves and lynx would have
been a constant threat.

Our woodlands now lack
these bigger predators.

Here on the Knepp
Estate in Sussex,

grazing animals have been used
to recreate a type of woodland

that once covered large
parts of the British Isles.

Wood pasture.

In just 20 years, this has
produced the conditions needed

by one of our most
spectacular insects.

The purple emperor butterfly.

It's midsummer, and
from the top of an oak,

the male can watch for females as
they emerge from the scrub below.

And he defends his tree-top
throne with great vigour.

He's one of our biggest butterflies
and will take on any intruder.

He even attacks passing birds.

But only one intruder
really matters -

another male purple emperor.

And one has appeared.

The two circle at high speed.

Only by slowing the picture down 30
times can we see what's going on.

They use their 8cm
wings as weapons,

attempting to knock each
other out of the sky.

The males only live
for a few weeks,

so it's all or
nothing in this fight.

Soon, a third male appears.

But the resident male
sees off his challengers.

His wings may be tattered,

but he's held on to his tiny empire
and, with it, his breeding rights.

The Atlantic oakwoods are one
of our rarest kind of woodlands.

High rainfall, numerous rivers,

and mild, humid conditions
create a lush environment.

These are temperate rainforests.

They have now been reduced to a
fraction of their original range

across western
Britain and Ireland.

In this patch, in an
isolated valley on Dartmoor,

a dream-like scene plays out
under the midsummer moon.

An ash-black slug.

Up to 30cm long, these are the
largest land slugs in the world.

They are almost exclusively
found in ancient, wet woods...

..and on this damp night, this
slug is looking for a partner.

It lays down a trail of slime which
carries powerful chemical signals.

The scent is an
irresistible invitation

to another ash-black slug.

Once the pair reach
the tree-tops...

..they become more intimate.

They nuzzle to make sure that
they're suitably matched.

Slugs are hermaphrodites,

each equipped with both male
and female sexual organs.

Preliminaries complete,

an overhanging branch provides
a hold for the consummation.

Twisting together,
they hang down as one.

Two penises start to protrude.

Entwining together,

each becomes as long as the
rest of its owner's body.

Each slug now passes a
packet of sperm to the other.

But the end of the
relationship is abrupt.

The left-over slime
is the only evidence

that the encounter
ever happened.

SQUAWKING

Back in the pinewoods of Scotland,
summer is the season of opportunity.

The cones at the top of
the trees are now ripe.

A male red squirrel
jumps into action.

He starts to feed on the rich,
oily seeds the cones contain.

But he is a messy eater...

..and his left-overs alert
others to what is now available.

A female.

She is late to the party.

High above, the male
sees her coming.

He's in no mood to share.

Driven off, the female
considers her options.

If she can sneak around
the other side of the tree,

she may be able
to arrive unseen.

But in this open woodland, that
is easier said than done...

..so she does the one thing a
red squirrel usually avoids.

She leaves the trees.

Leaping from tree to tree
in old-growth pine woods

is usually impossible, so the
deer path is her only option.

That ends where the pine
trees give way to birch.

These quick-growing trees
stand between the pines

and their slender branches provide
alternative access for the female.

One last obstacle remains.

Get this wrong and
it's a long way down.

She's made it...

..back to the tree with
the ripe pine cones.

And the male hasn't
even noticed.

For now.

It's the end of July
in the New Forest.

Two honey buzzard chicks are
squabbling over their breakfast.

It's late to be nesting, so
they need to grow up fast,

and although a frog is not
their favourite food...

..beggars can't be choosers.

Frog dispatched, a decent
meal finally arrives.

It's the comb from
a wasp's nest...

..packed full of
protein-rich grubs.

This explains the timing.

Their parents migrated
here from Africa to nest

just as the wasps reach their
peak numbers in the late summer.

BUZZING

With a ready supply of rich
food finally established,

the chicks grow extremely fast.

And they continue to fight.

But, in typical
British fashion...

..the weather makes things
a bit miserable at times.

It could be why honey buzzards are
one of our rarest breeding birds.

You can't always rely on
a ready supply of wasps

with summers like ours.

By mid-August, the chicks
are growing proper feathers.

The males are mousy-brown

and the female has a
handsome white head.

She usually dominates when it
comes to squabbles over food.

But there is plenty
to go round...

..if you can get
your beak on it!

Some of the wasp larvae in the
nest are hatching into adults...

..but overlapping feathers provide
protection against possible stings.

And a third transparent eyelid,

called a nictitating membrane,

protects their eyes.

It's fast approaching
the time when the chicks

will have to leave the nest
and fend for themselves.

Flapping the wings
builds their strength.

And every day the
chicks gain confidence.

If not elegance.

By late August, their
time has come to leave.

The female chick takes
her first ever flight.

Followed a few flaps
later by her brother.

They will soon set off on a
3,000-mile journey to Africa...

..escaping the approaching
chill of our autumn days.

With the arrival
of the new season,

our woodlands
begin to shut down.

The leaves change colour...

..and a hush descends
on many of our forests.

But not all of them.

ROARING

Fallow deer bucks have gathered
to fight for the right to mate...

..advertising their
presence by roaring.

They were introduced in the
11th century by the Normans

and initially kept
in private parks.

But they soon escaped and spread
across much of the British Isles.

The does watch on.

They're likely to
mate with the biggest

and most persistent
roarer here...

ROARING

..but the choice is theirs.

Some males thrash
the undergrowth.

ROARING

And antlers become
adorned with foliage.

This young buck...

..has yet to impress.

But he hangs around the
edges, just in case.

The frequency and
quality of a buck's roar

is an indication that
he's in good condition.

BUCK ROARS

But, if a challenger approaches,

the next step is
the parallel walk.

If it's an obvious mismatch,

they might still
save their energy.

But this looks as if it
could be a fair fight.

ANTLERS CLASH

The bucks can weigh
up to 100 kilos.

A wrong move now could be fatal.

In the pandemonium, other
males join the battle.

BUCK ROARS

As they fight, the
does sidle away.

They join the small male
on the edge of the wood.

Although his technique still
needs a little improvement...

..this could be the
young buck's lucky day.

SOFT ROARS

As the sounds of the rut fade,

hitherto hidden players in
the woodland drama appear.

Fungi.

The cool, wet days trigger
an eruption of mushrooms

and toadstools across
the forest floor.

These are the fungi's
fruiting bodies

and they have just
one function -

to spread their spores.

Some simply allow their spores
to slip out of the gills

beneath their caps.

Others wait for a gust of wind
to carry theirs into the air.

Puffballs rely on the rain.

One droplet is enough to trigger
the projection of a puffball's

spores far and wide.

Mushrooms and toadstools
can be highly visible,

but they are only a tiny
part of each fungus.

And it's only recently that we
have started to understand what

some of these organisms are doing
when they're out of our sight.

Underground,

mycorrhizal fungi send out
a web of tiny filaments

called hyphae.

These soon encounter tree roots.

The two organisms then connect.

And now they can
share resources.

The fungus gets
sugars from the trees,

and the tree gets water and
minerals from the fungus.

And the sharing
doesn't stop there.

The fungi link trees
and plants together

in a mutually beneficial
network called, by some,

The Wood Wide Web.

We can see how this web works

by speeding through the year
in this Suffolk woodland.

After a winter of dormancy,

the woodland in
spring bursts to life.

Excess resources stored
by the mature trees

move through the fungal web

and give sprouting
saplings a good start.

But new growth
attracts leaf eaters.

Plants under attack
emit distress signals.

By using specialised equipment,

we can listen to these signals
as they travel through the web.

WHISTLES AND BEEPS

This is the sound of
plant communications,

and those that detect it can
activate chemical defences

so that if they are attacked,

their leaves are
already distasteful.

Summer brings its
own danger - drought.

Young trees may struggle

as their limited liquid
reserves are depleted.

But the network can come
to their rescue once again.

Water moves from deep-rooted
trees to others in greater need.

These complex relationships
exist in every woodland,

and 90% of all our
plants depend on them.

But such networks
take time to develop.

Ancient, diverse woodlands

have more fungal connections

and support more life
than young plantations

that contain just
a single species.

Such monocultures usually consist
of fast-growing, non-native trees,

that today account for almost
half of all our tree cover.

This plantation,

hemmed in by farmland on one side
and Bodmin Moor on the other,

is cold, dark, and inhospitable.

But birds are using this
wood as a temporary home,

and its branches are
caked with the evidence.

As the late winter
sun begins to sink,

the tenants return.

RUSHING SOUNDS

Starlings.

They've been out
feeding all day,

but, as the cold night draws in,
their numbers start to increase.

Up to a million birds will
use this small plantation

as their overnight roost.

But others know this.

Buzzards hope to snatch a weak
bird from amongst the flock.

TWITTERING AND RUSHING

And, up above, a peregrine.

The starling flocks
swirl and coalesce

as they react to the
predator's presence.

There's safety in numbers.

By gathering in huge flocks,

the chances of getting caught are
reduced enormously for any one bird.

The light starts to fade,

and the starlings
come down to roost.

As their numbers increase,
so does the noise.

INTENSE TWITTERING

In this chatter is information.

Birds continue to join the roost
long after the sun has set...

..revealed by thermal cameras.

They pack ever more tightly
into the plantation.

Until, to our camera,

the trees are illuminated
like skyscrapers at night.

In close-up, it becomes clear

that there are vigorous
arguments over the best perches.

Because, even now, the
starlings are not safe.

A barn owl.

Wraith-like, it hovers
above the roost,

causing panic among the
birds perched beneath.

The owl takes its time.

It is a remarkable
hunting technique,

revealed for the first time

by using these
specialist cameras.

As soon as dawn arrives,

the birds leave to
resume their feeding.

The size of these winter
flocks may give the impression

that starlings are doing well,

but in fact, their
numbers in recent years

have diminished by 80%.

Our woodlands are now expanding,

but the new plantations are
mostly of low diversity.

We need to give better protection to
the native woodlands that remain...

..restore those
that we have lost...

..and allow our trees the time
and space to spread, naturally.

It will take many years to recreate
anything as rich as the woodlands

that we once had...

..but surely it should
be our target to do so.

To reveal the intimate lives of
two very different bird species,

two teams filmed in two
distinct types of woodland

at opposite ends of our isles.

In Scotland, a family of eagles

take advantage of the open and
spacious old growth forest.

While in Cornwall, this
dense strip of plantation

is a winter roost for
nearly a million starlings.

They're well known for their
astonishing murmurations,

but the team want to get
a more intimate look,

and reveal what goes on
in the roost after dark.

To do that, they need to get
amongst the closely planted trees,

where it's dark, lifeless
and rather smelly!

Urgh, that's gross.

This all looks pretty fresh.

You can see, like, a good
couple of centimetres

of bird poo on the branches.

As well as the visuals of
all the birds coming in,

we're trying to get... I'm
really keen to try and get

a real multi-sensory
experience as much as possible.

Sadly, we can't share the smell,

and it's coating the ground
as well, so there's probably,

yeah, a good...

..four or five centimetres
of bird poo there as well.

So this definitely feels like

it probably is the
centre of the roost.

Having sniffed out the roost,

the team build a platform

so that they can rig
remotely operated cameras

up in the canopy.

We've got the full tower up
now, so we're pretty much

at the top of the trees,

which really feels like you're
in the middle of the roost.

Hopefully the birds
will surround us

and we'll be able to get some nice,
intimate close-up shots of them.

The remote cameras allow
cameraman Jo Charlesworth

to hide out of sight below.

So, everything's working.

As long as the birds don't fly
into the other end of the woods,

it's just a case of
waiting for them to arrive.

450 miles to the north,

cameraman Hamza Yassin is
searching the Scottish Highlands

for golden eagles,
and their nest.

I'm hiking through this amazing,
amazing ancient woodland.

There's still snow on the
ground as you can see,

and it's Baltic!

With only 20 pairs of
tree-nesting golden eagles

in the whole of
the British Isles,

finding a nest that the team
can film is no easy task.

Hamza climbs to a
good vantage point,

where he can scan as much
of the forest as possible.

It's a waiting game.

So, I'm scanning the
high ridge line there,

waiting for the golden
eagles to pop up,

and then figure out
where they're coming

down to their nest.

Yes, we have contact!

The first golden eagle
has been spotted,

and it's only...
6:30 in the morning.

Come on!

Their nest is
likely to be nearby.

They're bringing in
nesting material,

which is the best thing ever,

but still doesn't show me
where the nest is exactly.

Halfway there, halfway there.

The next day, Hamza drives closer
to pinpoint where they are.

Ooh, here we go, here
we go. Come on...

Ah, finally!

An adult leaving the nest

reveals its exact location.

Three days' work has paid off.

That's incredible.

The team can now return
later in the year

to film the chicks
when they hatch.

In Cornwall, the starlings are
arriving back at their roost.

Jo's hard work pays off,

and he captures the starlings

as they crowd into the
canopy around his cameras.

It gives a unique insight into
what it's like to be amongst

a million roosting birds.

TWITTERING

And the team also record
the sound of the flock

as they settle
down for the night.

INTENSE BIRD CHATTER

This is actually insane now.

We're literally in the
middle of a starling roost.

But the following day,
the roost is silent,

the birds have disappeared.

You would have thought a
million birds, or thereabouts,

might be quite easy to spot.

Apparently not.

We're pretty sure they
must be in the area, but...

it's a big old area.

While Chris has lost a
million birds in Cornwall,

in Scotland, the eagles are right
where the team want them to be.

In a hide installed
by the estate,

cameraman John Aitchison is able
to film right into the nest.

So, at the moment, I
can see in the tree...

which, I have to say,

is probably the most beautiful
eagle's nest I've ever seen,

in the top of a big Caledonian
pine - a Scots pine tree.

They're just carrying
on with their lives.

Especially if I'm quiet,

I shouldn't make any
difference to them at all.

Director Lily watches from
the other side of the valley.

They're exceptional parents.

They're bringing
in food constantly.

That nest is so well-stocked.

The hard-won view of the
rare nest gives the crew

a special insight into the lives
of these tree-nesting eagles.

There's so many things
that I've learned

over just these ten
days being here,

and it's been a real privilege
getting to know these birds.

Capturing these intimate moments

took a huge effort
from the crew,

working alongside the local team

who protect this ancient
forest and its inhabitants.

Back in Cornwall, the team
have found the starlings,

and it's time to take
things a step further.

A thermal imaging camera allows
them to film the starlings

in a new way, revealing their
behaviour in the roost after dark.

There's something very
Christmassy about it.

All these trees
festooned with light.

And they capture the exact moment
that a night-time predator arrives.

Yes! Yes! Good spot.

A barn owl, only visible with
the help of the thermal camera.

The intimate moments captured
in these very different forests

are proof that many
spectacular animals

still call our woodlands home.

These are important habitats.

From the gorgeous,
gorgeous golden eagle

up in that nest
in the Cairngorms,

down to the starlings using
this apparently pretty low-grade

woodland on the
edge of Bodmin Moor,

every little bit
is really important

and we've got to look after it -
it's precious and it's special.