Woodland Britain The Nature of Britain

It's 3:30 in the morning.

Now it takes something pretty special to get me out of bed at this time of day,

but I've come to see the start of a spectacular daily show.

-BIRDSONG

-Here we are, best seat in the house and I think I'm only just in time.

The overture's beginning. Who's first up?

The robin!

Blackbird...

Song thrush - always nice to hear.

One starts and then suddenly within seconds, they're all joining in.

It's as if they're all taking their four-part harmony now.

So, woodland that five minutes ago was absolutely silent

is now ringing.

It's the most evocative sound in our wildlife year.

At its peak, more than 70 million birds across the country join the spring dawn chorus.

It signifies a special place, a wildlife habitat packed from floor to canopy.

The forest is a magical and mysterious place.

The source of folklore and fairytales.

It's plain to see how ancient peoples conjured up all manner of mystical beasts

to live among the gnarled branches and forest mists,

but the real forest is even more extraordinary.

So join me on a journey where the plants and animals might seem familiar,

but the way in which they work together may come as a surprise.

Woodland is one of our richest habitats, but you'd be hard pressed to see what's living here at all.

Wildlife's very good at making itself scarce, especially our first little television star.

Its nickname is "the monkey of the forest" because it spends all summer up in the trees,

but in winter and early spring, it sleeps and is almost impossible to find.

It's the dormouse,

one of the few British mammals that truly hibernates.

It finds a comfortable winter nest site,

not up in a tree but on the ground.

Its body almost shuts down.

Its temperature falls to that of its surroundings

and its heartbeat slows down to a tenth of its normal rate.

It uses so little energy, it can go for weeks, even months, without moving.

But on warm winter days, the dormouse can wake for a short time, but that uses up valuable energy

so it goes back to sleep and the temperature drops.

Come the spring, its entire body kicks back into life,

but it doesn't venture far, because the dormouse's summer world doesn't exist yet.

There are no leaves on the trees to hide it from predators.

In winter, many of our woodland plants lie dormant too,

but with the slightest hint of spring,

the earliest flowers start to bloom.

It may seem a slow and gentle affair but there's urgency here.

This sudden burst of spring growth taking advantage of something all plants need to grow...

light!

Leaves have yet to appear on the trees, but when they do,

they'll cut off the light to the woodland floor.

So there's a race on.

All the early spring flowers must grow before that light's blocked out and to do that,

some of them have a hidden store of energy that gives them a head start.

The primroses are out already.

These wonderfully bashful, sulphur-yellow faces

and all around them, the leaves of bluebells.

In a couple of week's time, this is going to be a sea of blue.

Of course, the bluebells have an advantage.

They have one thing the gardener knows about at their roots...

a bulb, a winter storehouse of food,

that come the milder temperatures of spring pushes them into life

and one of the first bulbs to emerge...

is the daffodil.

It's a flower show more impressive than anything we can stage.

Following daffodils are lesser celandines.

Then come ramsons, the old English name for "wild garlic".

Next up are wood anemones.

And finally...

bluebells.

With maybe half the world's population in the United Kingdom,

British woodland is the last stronghold of the native bluebell.

But this spring race isn't confined to flowers on the forest floor.

The growing leaves will not only cut out light but also dampen sound.

So, the great spotted woodpecker stakes his claim to a territory

before they appear and risks a serious head injury for his trouble.

He drums rather than sings

and he's saying, "I'm here and this is my patch."

It's the original trunk call.

He always uses the same tree as a sounding board.

You can tell by the number of holes in it and the more resonant it is, the further the sound carries,

up to half a mile in some cases.

It's the human equivalent of hitting a wall face first at up to 20 mph.

This rush to beat the emerging leaves is joined by some of the trees themselves,

especially those producing wind-borne pollen.

Before their own leaves interrupt the flow of air in the woodland canopy,

willow and hazel join the race to flower.

Eventually, the leaves unfurl

and the colourful woodland display comes to an end.

By May, the trees close the canopy and switch off the light.

The show on the forest floor disappears

and our spotlight falls on the creatures hidden away in the depths of the forest.

With the leaves providing an effective hiding place,

our "monkey of the forest" behaves just like...a monkey.

The dormouse's world is the leafy canopy.

Now he's wide awake, he needs to make up for his winter fast

and the tree provides something especially juicy.

Feasting on its fresh green leaves are newly hatched caterpillars.

They're packed with protein, just the thing to set up a dormouse for his frantically active summer.

The rapidly spreading leaves are the chemical factories

that provide the tree with its own food,

but as with anything in nature,

if you provide something that's remotely edible,

then something'll come along and eat it.

Even with the canopy closed, the floor of most British woodlands

still receives sufficient light for ferns and other undergrowth to grow,

but the beech wood, like this one near Oxford, has virtually nothing growing on the forest floor.

There's a very good reason for that and it's right above me head.

The beech leaves fit together so closely,

almost like the pieces of a jigsaw,

that very few chinks of light make it down to the forest floor,

as a result of which the ground beneath me feet

is almost completely devoid of life but there is one survivor.

This is the bird's nest orchid.

It might not look much, but there's a good reason for that.

It grows in the gloom where nothing else can,

and that means it can't manufacture food with the aid of sunlight and photosynthesise.

That's why it's this kind of cream colour

and its leaves have been reduced to these scales,

but if it can't manufacture food with the aid of sunlight,

then it has to find alternative means of nourishment.

The orchid thrives with the help of a fungus

that lives in the soil and breaks down rotting vegetation.

The nutrients it absorbs are hijacked by the orchid.

But the orchid gives nothing in return.

It's a parasite.

So by taking advantage of the fungi,

these delicate flowers are able to survive

in the dark underworld of the beech forest,

where less well-adapted species simply fade away.

With so little light and therefore warmth getting through the canopy,

flying insects like butterflies tend to make for the woodland edge.

It's where they'll find the later flowers and the instant energy their nectar provides.

But in a wood in Hampshire, there's a butterfly that's turned its back on all that

and it's one creature I'd especially like to meet.

But to see it, I need to get up there.

"THUNDERBIRDS" THEME PLAYS

Lovely!

Apparently, this is their favourite perch

and they generally turn up about noon.

Near enough. OK, do you want to turn her off? Thanks.

Hah!

That's a leaf.

And here it is... a purple emperor butterfly,

foxy and creamy on the underside of the wings

and iridescent purple on top. Absolutely beautiful.

And they're very active.

Each male butterfly circles in the light,

defending its own patch of the woodland canopy.

They'll even see off small birds rash enough to venture into the butterfly's airspace.

And they go to so much trouble because they have a sweet tooth.

Butterflies drink nectar, but there are no flowers up here to provide that

so they need to find another way of getting at it.

Now butterflies can't pierce leaves but these can.

Aphids. And they're very messy eaters.

Aphids tap into the tree's sugar transport system.

They stab the leaf vein with their needle-like mouthparts and feed on the sugary liquid.

The system's under high pressure, so they don't need to suck.

The sugary solution gushes into their stomachs and even spills out of their rear ends.

The result is a "rain" of sticky, sweet droplets that drip onto the leaves below.

It's a bit of a nuisance when you park your car underneath,

but for the purple emperor, it's manna from heaven.

Using its long proboscis, the butterfly sucks up the sugary puddles.

So by breaking that traditional tie between the butterfly and flowers, the purple emperor

has managed to find itself a whole new lifestyle in the forest canopy.

Now you'll only hear this sound if it's dead quiet.

MUFFLED SCRAPING

It's made by something you'd meet more usually out in the open at a picnic or in the backyard.

But actually the wasp is more at home in the woods.

The wasp is scraping wood, not to eat,

but to chew into a pulp and then manufacture its summer home.

It's a house made entirely of paper

and the workers construct it one layer at a time.

Deep inside the nest, neat rows of nursery cells contain the growing wasp larvae.

The workers feed them chewed up caterpillars

while the wasps themselves feed on nectar that's passed from one wasp to another.

It's all very organised - a wasp-making assembly line.

And there's one creature that's travelled all the way from Africa

to a wooded Welsh valley to cash in on the product they're making.

It's a honey buzzard,

a bird of prey, but one that behaves in a very unusual way.

It breaks into wasp nests but there could be 10,000 angry workers living inside,

and they may be small but what they lack in size,

they more than make up for in ferocity.

The buzzard's well protected.

Tightly-packed feathers on its head and face repel stings

and protective lids prevent damage to its vulnerable eyes.

The attacks, though, are relentless.

Each time a wasp stings, it releases a chemical that encourages other wasps to join in,

but they're not the only ones using chemicals to communicate.

The honey buzzard itself releases a smell that serves to calm the wasps.

Although they swarm around the bird, they seem to have forgotten what they're angry about!

Unlike other birds of prey,

the honey buzzard has a delicate beak with which it picks out the tasty grubs.

It rarely destroys the entire nest, but leaves part

so workers can rebuild it and then it'll return for a second helping.

After eating its fill, the bird carries a portion of the wasp nest back to its own nest,

where its chicks are already adept at winkling out the grubs.

So next time wasps cause you a nuisance,

remember they also bring the magnificent honey buzzard all the way from Africa

to breed in our woodlands each year.

The woods and forests we've visited so far

have broad-leafed trees that thrive in the relatively mild conditions

that persist almost all year round in much of England and Wales,

but north of the border, things are very different.

In the more remote parts of Scotland,

trees must cope with probably the most unforgiving climate in the entire country.

The Great Caledonian Forest once covered much of the Scottish Highlands,

but due to a change in our climate and the felling of its trees,

the forest today is a shadow of its former self.

The trees are pines, birch, aspen, rowan, and junipers

and they're beautifully adapted to the harsh conditions that prevail in the north.

The land can be covered in snow for up to a hundred days of the year,

but the conical shape of many trees ensures the snow slides off their branches so they don't break.

The sap contains antifreeze so the water inside the tree doesn't turn into ice,

and of all the Caledonian trees,

the toughest must be the magnificent Scot's pine.

It's the world's most widespread conifer,

and there's one important adaptation that enables it to grow in the most unexpected places.

The rockface below me is exposed to all the elements

- wind, rain, snow and ice,

but amazingly, some trees manage to grow even here.

Against all the odds,

this pine tree here has managed to establish itself on this sheer rockface.

There's hardly any soil here and consequently hardly any moisture

and what there is freezes in winter.

Temperatures here can fall to minus 20 degrees

and winds can reach speeds of up to 140 miles an hour.

So how does it survive?

By using these...

pine needles.

They are leaves, but they're very, very narrow and they're covered in a waxy coating

which hangs onto as much moisture as possible,

so whilst deciduous trees shed their leaves in autumn and grow new ones each spring,

the pine hangs onto its leaves all year round, saving itself the energy.

And up among its branches, it also has pine cones growing throughout the year.

In Scotland's Cairngorms, this gives rise to a sound you wouldn't expect to hear in the depths of winter.

TWEETING

They're chicks - crossbill chicks.

It's rare to find baby birds like these in winter

because chicks need heaps of food and it's just not available at this time of year.

But pine cones allow crossbill chicks to get an early start.

The seeds, the pine kernels,

are locked away inside the cones and early in the season when the cones are barely open,

birds can't get at them. All, that is, except the crossbill.

You've heard of cross-eyes.

Well, this bird has cross-bills, hence the name.

It's the only bird in the world

with the upper and lower parts of its bill crossing over when the bill's closed.

It's the perfect shape to prise open the woody scales of a pine cone

and get at the seeds inside.

It seems to behave more like a parrot than a songbird.

With the scales prised apart,

it uses its highly flexible tongue to pull out the seed.

By adopting this breaking and entering technique,

the crossbill opens a treasure chest of food,

allowing it to bring up its young at what seems to be the worst time of year...

..and be one step ahead of all the other birds in the wood.

Winkling out pine kernels is one thing but eating the pine's needle-like leaves is quite another,

yet surprisingly they provide the energy required for Mother Nature's variation on the Highland fling.

TAPPING AND SQUAWKING

Spring on the shores of Loch Garten in Speyside is marked by another unusual sound.

It's the male capercaillie.

He's strutting his stuff and calling to attract the ladies.

They quite literally fall at his feet.

TAPPING AND SQUAWKING

In fact, we only hear part of the call.

One component is so low-pitched, we can't hear it at all,

but low frequency sounds travel well in the forest,

attracting hen capercaillies from far and wide.

Combined with his swaggering courtship dance,

he cuts a fine figure, but he contributes virtually nothing to bringing up the brood.

The capercaillie is one of the few creatures that can digest pine needles

and as they're on the tree all year round,

there's plenty of food for the female birds to feast on.

They don't need the males. They can rear their young on their own.

So, the males have nothing else to offer the self-sufficient females,

but their courtship display.

Oh, and the contribution to the genetic makeup of their offspring!

And when the pine needles fall from the trees, they're not wasted.

They don't break down quickly like broader leaves

so they're used not as food, but as building materials.

And the builders are ants

- wood ants.

This mound isn't an untidy heap of pine needles.

There's order here.

The needles are placed in such a way that rainwater is shed just like a thatched roof on a cottage.

The side facing the sun is also slightly flattened to warm up the nest

while workers block and unblock the nest entrances to control the temperature and humidity inside.

They also sit on the top, sunbathing,

not some sort of ant siesta,

but a means of taking the sun's warmth down to the brood chambers

deep inside the nest and warming up the young

- miniature storage heaters on legs.

The ants return the gift of building materials

by protecting the pine trees from leaf-eating insects.

Some caterpillars are able to digest the needles and could make a sorry state of the tree,

but the wood ants come to the rescue.

They kill the caterpillars

and then carry their victims back to the nest.

In fact, wood ants are so important at keeping pests at bay

that they're key players in the preservation of these ancient pine forests.

There are over 80 pockets remaining today,

but at one time the forests were so thick and covered so much of Britain

that a squirrel, if it had a mind to, could have scampered all the way

from the north of Scotland to the south coast of England without ever having to touch the ground.

It's hard to imagine that these manicured fields and patches of woodland

were once covered by a vast unbroken forest.

It was filled with game, including an animal that was hunted out of existence in this country.

But after an absence of 300 years, it's back.

It's the wild boar.

It's escaped from farms and now it's set up home in woodlands in several parts of southern England,

like the Kent and Sussex border and the Forest of Dean.

In the wild, they feast on beech mast, when it's in season,

and to make it, the beech tree has struck up an intimate relationship with another living thing.

To find out what led me to a friendly encounter with some close relations of the wild boar.

Pigs - they're quite keen on biscuits. Here you go.

But they're even keener on something else

and they're very good at finding it.

Oh, look what she's found! Pigs will do anything for a piece of this.

It's a summer truffle and pigs share their predilection for them with many a wealthy gastronome,

but it's more than just a tasty titbit.

It's a kind of fungus

and beech trees rely completely on fungi like this for their survival.

It's incredible that something so big can rely on something so small.

If I asked you how trees manage to get hold of water and nutrients,

you'd probably say through the roots but that's only a part of the story.

They couldn't do it at all without these...

..fungal strands.

Mycelium, it's a kind of symbiosis. The fungus passes minerals and water to the tree

and the tree, in return, passes sugars to the fungus, so they're both winners.

So, down there in the soil, we have the real engine room of the forest

and the amount of filaments, roots and rootlets -

the intricate pipe work that joins it all together - is staggering.

If you were to unravel the tree's roots,

they'd stretch for five miles. Pretty impressive, eh?

But if you were to unravel its fungal mycelium,

that would stretch right round the globe!

It means this beech woodland relies for its nutrients

on a vast network of tiny underground fungal threads.

So the next time you see a massive beech tree,

just pause for a moment and reflect on the fact that it owes its entire existence

to something as small as a summer truffle.

There you go.

In fact, without fungi, nothing in the forest would grow

and although it's another part of the woodland that we don't tend to see,

the total weight of fungi in the soil approaches that of the trees themselves.

The only time we do see them is when they reproduce.

Some rely on wind to carry their spores up into the air.

The stinkhorn gives off a smell that attracts flies

and they spread the spores far and wide.

The ink cap releases them as the fungus decays into a black mushy soup.

The bird's nest fungus forms the perfect cup.

Raindrops falling into its centre splatter the spores

so they bounce out of the cup and onto the ground.

Raindrops trigger the puff in an earthstar's puffball

to help release its cloud of tiny spores.

And all these fruiting bodies

provide an instant takeaway for woodland animals.

Of course we like mushrooms too, and of the six thousand species in Britain, many are edible.

A deadly few though are poisonous enough to kill us

and they have an uncanny resemblance to the ones we like to eat.

This is a true morel, a fungus found in woodland.

This is the false morel.

Now the true morel is edible and very tasty.

But this one, when ingested in your stomach,

produces a chemical that's found in rocket fuel.

You will die a lingering and painful death.

I've got the right one...

..I think!

The morels appear in late spring and early summer,

but most mushrooms send up their fruiting bodies later in the year,

when the atmosphere's warm and moist.

They tell us that another change is in the air

- the slow transition from summer into autumn.

It's another time of woodland plenty.

Trees spread not spores like fungi, but seeds,

and they're often as not wrapped up in a sweet-tasting fruit or berry,

a slowly ripening feast, not only for the palate but also for the eyes.

There's something about the colour red that makes fruits and berries

totally irresistible to woodland animals.

It's one way a tree enlists help to spread its seeds.

Birds provide a free courier service.

The seeds hidden inside the berries aren't digested,

so they pass through the bird's gut, only to be deposited some distance from the parent tree

complete with a dollop of fertiliser to help kick-start their germination.

So, berries and fruits are not only vital to the tree,

but also to the rest of woodland life.

These fruits could mean the difference between life and death for the dormouse,

which must put on enough fat to survive the coming winter.

And when it's run out of fruits, there are always nuts.

With the trees producing so much food at this time of year,

woodlands are a magnet not only for the fruit and nut eaters,

especially the mice and voles,

but also the animals that like to eat THEM

and it's at night in a Somerset woodland

that you'll find the feast is in full swing.

This glut of food, though, means that the local rodent population goes into overdrive

and one woodland resident can take full advantage of it.

See if I can rustle one up and to do that, I'll need one of these,

see if I can find the right track.

HOOTING

There we go.

-HOOTING

-An owl.

Wait for it...

-HOOTING

-There we go, it works!

OWL HOOTS

As the evenings draw in, our forests ring to the well known call of our commonest owl, the tawny.

It's only about at night and it's beautifully camouflaged,

so although you hear it, you seldom see it.

OWL HOOTS

Now what you might not have realised is that this isn't one owl calling, it's two.

OWL HOOTS

It's a duet between male and female.

The female is doing that rather shrill "k-wick"

and the male is a much more sonorous "too-woo".

The reason we notice them more in early autumn

is that it's the time of a tawny owl teenage rebellion.

The chicks' demand for food is unrelenting

so after three months, the parents kick them out, which creates a serious real estate problem.

Who-oo's going to live where?

And that's where the calling comes in because a battle royal now ensues,

certainly in terms of just calling each other names.

All these youngsters are vying for their own territory,

often to the consternation of the adults who already occupy it.

The timing's critical.

If there was little food around, the young owls would starve,

but with so many fruits and nuts, the rodent population is at its peak,

providing plenty of easy to catch meals,

a life saver for a juvenile with limited hunting skills but bad news for dormice.

SCREECHING

The tawny owl has such good hearing, it can pick up the slightest rustle

and home in on its target with pinpoint accuracy and all in the dark.

Don't worry, our dormouse is safe.

But a wood mouse isn't so lucky.

The dormouse will live to scamper another day.

Accuracy is also the hallmark of another group of nocturnal predators, the bats.

HIGH-PITCHED CHATTERING

Like owls, they rely on sound to hunt in the dark,

but they also use sound to find their way about.

It's called echolocation.

They emit a sound and then listen for the returning echo.

Now we can't hear it, it's so high pitched,

but we can if I use this - a bat detector.

This will lower the frequency and make it audible to us through this little speaker here.

Different bats yell at different frequencies and I can adjust the frequency on here

which'll then tell me which bat I'm listening to.

RHYTHMIC BEATING

Whoa! According to the frequency, that was a pipistrelle, a little tiny one.

DEEPER RHYTHMIC BEATING

That's Daubenton's bat.

FAINT RHYTHMIC BEATING

That was a serotine.

This whole woodland is alive with the sound of bats yelling their heads off,

but they're not calling to one another. They're sending out those noises

and listening for the echoes coming back through the wood.

With this echolocation system,

a bat can lock onto moths flying in complete darkness with consummate ease,

but one species of British bat specialises in catching other kinds of prey.

You'd think that something like this spider here,

tucked safely away in its silken web,

would be safe from flying predators but then you'd have reckoned without a woodland specialist...

Natterer's bat.

This bat is what's known as a "gleaner".

It plucks prey off the vegetation

or in this case, a spider straight out of its web.

On our journey around British woodlands,

we've been to the Cairngorms and South Wales,

to Oxfordshire and Devon,

the New Forest and the Forest of Dean

and we've seen all sorts of amazing plants and animals,

but maybe there's something important that, so far, we've left out.

There's one central silent player in this woodland drama,

on whose yearly cycle all the other inhabitants depend...

the tree.

'It's the tree and the way it changes through the seasons

'that determines the pace of woodland life'

and it's the tree that provides nourishment and shelter for everything that lives here.

The oranges, yellows and browns of autumn are its final extravagant flourish

before its leaves die and fall to the ground.

For our dormouse, the autumn change means his entire world is falling down about him,

so with little to eat and nowhere to hide,

he simply makes a winter nest in a convenient hollow and goes to sleep.

His name, dormouse, means "sleepy mouse".

He'll sleep now for up to six months

and as long as he's well fed during the summer,

he'll wake again in spring.

If he hasn't, then it's a sleep from which he'll never wake.

The trees themselves shut down during winter,

but in this constantly changing environment lives an animal community,

most of whom are active throughout the entire year.

And what of the future?

Well, the good news is that over the next 100 years or so,

there are plans afoot to restore and enlarge our areas of broadleaf woodland

so there will be more space for wildlife.

Of all our habitats, woodland has the greatest variety

and the largest number of plants and animals.

They may be hard to spot, hidden away among the trees,

but at least now that we know some of the places to look,

that weekend walk in the woods should be all the more rewarding.

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