Original subtitles

WAVES CRASH

SIAN PHILLIPS (VO): Church Rock, Pembrokeshire

on a mid-winter morning.

An Atlantic storm blows in on the wild Welsh coast.

With it come waves up to 10 metres high.

They batter the cliffs.

Winds can roar up to 80 miles an hour.

WIND WHISTLES

SEABIRDS CRY

On days like this, only a few brave seabirds

dare take on the fury of the ocean.

Incredibly, some coastal birds relish the storm winds.

BIRDS CAW

Choughs.

Rare, red-—legged members of the crow family

found at the land's edge.

Here, they spiral into the air

twisting and turning in the eddies.

Welsh legend ties them to the very soul of King Arthur.

This coastline is imbued with magic and mystery.

BIRDS CHEEP

It's a harsh place to carve out a life.

BIRDS TRILL - SEALS WAIL

Bringing unique challenges.

This is a story of life on the edge.

Wales is a coastal nation.

The sea is in our soul.

Full of hidden treasures...

wonders...

and giants.

A sea of mythical coasts...

with extraordinary creatures...

secretive shallows...

...and hidden depths.

These are the Wonders of the Celtic Deep.

Over 1,600 miles long

the rugged coastline of Wales is peppered by rocky outcrops

and remote islands.

Lighthouses warn ships of the treacherous reefs

and deadly ocean currents.

Over the centuries, thousands of seafarers have come to grief on these shores.

Their souls trapped in these waters forever.

Ghostly shipwrecks litter the sea floor.

Twenty miles off the coast of Pembrokeshire

eery moans ring out from the sea washed rocks

around the Small's Lighthouse.

But these aren't the cries of drowned sailors.

EERIE WAILING

They're the siren songs of one of Wales's most successful marine mammals.

SEALS MOAN

The Atlantic grey seal.

Over 5,000 live off the coast of West Wales.

MOANING CONTINUES

They rest on the shoreline to recover from the long hours spent at sea.

Some have travelled hundreds of miles in search of a meal.

Their streamlined bodies and large flippers

are built to speed them through the testing waters.

But today, the hunt is not for food.

This young female is on the lookout for love.

She's set her eyes on a handsome young bull seal

sunbathing on the rocks.

Maybe a seductive dance will catch his eye and lure him into the water.

SEALS MOAN

SEAL GRUNTS

He's not impressed...

and falls asleep.

So his young admirer follows suit.

SEAL GRUNTS

Astonishingly, seals can sleep in the sea.

A thick layer of blubber protects her from the cold Atlantic waters.

At last, the male has woken and takes to the water

allowing her another chance to show off her moves.

Once underwater, she takes things slowly.

Seals can stay submerged for up to half an hour.

Plenty of time for a flirtatious game of hide and seek.

With excellent underwater eyesight

she'll have no trouble keeping tabs on her intended.

The dense kelp forest provides a perfect playground.

Scent and touch are very important in seal Communication and courtship.

Sealed with a kiss.

A playful scratch...

and he's completely under her spell.

Our sleepy Romeo looks lovestruck.

But after this afternoon's seaside romance

the amorous couple will go their separate ways.

These ancient rocks were formed millions of years ago.

The constant assault of wind and waves has reshaped the shoreline

creating spectacular rocky fortresses.

A magnet for human adventurers.

And an ideal spot for one group of animals to raise their young.

BIRDS CAW

South Stack, Anglesey.

BIRDS CAW

For a few weeks each year

these normally barren cliffs are transformed into seabird cities.

Around 11,000 guillemots make their homes here.

Guillemots spend most of their lives far out at sea

but each summer, they return to the same tiny ledge to breed.

They pair for life.

Preening is a way for couples to re—connect and confirm their bond.

This couple have a newly laid egg to keep safe.

It's the only one they'll produce this year.

It sits precariously on a ledge that's just a few centimetres wide.

Living beak by jowl can be highly stressful.

But there is safety in numbers.

Raven raiders roam this neighbourhood

and guillemot eggs make a nice breakfast.

But they're not the only ones in search of a meal.

Predatory gulls patrol the cliffs.

GULLS CRY

By creating chaos

the gulls try to force the guillemots to expose their eggs.

GUILLEMOTS CHEEP

Our couple's precious egg is safe for now

but the gulls redouble their efforts.

They stay firm.

These great black—backed gulls are ruthless predators.

Few guillemot parents can withstand a direct attack.

Ours have been spared.

The egg is safe for now but the hunters will return.

They must remain on guard if it's to hatch into a healthy chick.

Kenfig Burrows.

Just a few miles from Port Talbot

this vast dunescape is covered with rare wildflowers.

BIRDS CHEEP - DOG BARKS

INSECTS CHIRP

In spring and summer, the whole coastline blazes with colour.

Thrift is especially adapted to the salt laden winds.

BEE BUZZES

The carpet of wildflowers provides a nectar filled paradise

for a host of insects.

SEABIRDS CRY

On the tops of Anglesey's sea cliffs, swathes of bell heather provide a home

for the rare silver studded blue butterfly.

The butterflies get their name from the metallic studs on their wings.

The males are a pale blue colour.

They live in tight-knit colonies

and are totally dependent on these remaining pockets

of unspoilt heathland.

On this warm summer afternoon, love is in the air.

The male butterflies hover above the heather

in search of the light brown females hidden within.

Once a male finds a receptive female

they attach the tips of their abdomens together.

She may only mate once in her life

and a few days after laying her eggs, she will die.

The male inserts a tiny packet of sperm into her abdomen.

It will take takes several hours to fertilise her eggs.

The pair remain locked together...

and wait out the day, here at the edge of the sea.

SEABIRDS CRY

Interspersed between the rugged cliffs lies a very different landscape.

Estuaries.

Gateways to the sea.

BIRDS CAW

Shifting landscapes of sandbars...

saltmarsh...

and twisting creeks.

Twice a day, these shallow waterways fill with the tide.

On this early May morning

a visiting sea mist envelops the Teifi Estuary.

This sheltered inlet is home to a huge variety of birds.

Dippers.

Kingfishers.

BIRDS CAW AND CHEEP

Stately swans.

In spring, the estuary is a flurry of new life.

Families of shelducks are moving in.

These diligent and experienced parents have still got seven of their ten hatchlings.

BIRD WARBLES

But these first-time parents haven't been so lucky.

Only three of their youngsters have survived.

Life can be brutally short when you make a tasty snack for predators.

BIRDS TWEET

At low tide, the mud banks are exposed

providing a rich feast of tiny worms and crustaceans for the hungry ducklings.

Mum is highly protective, but being on shore brings extra risks.

A killer stalks the banks.

The family of seven immediately escape to the safety of the water.

But our new parents are oblivious to the approaching danger.

These bitesize balls of fluff

make a delicious lunch for a hungry fox.

Spotted.

Mum and Dad round up their offspring in the nick of time.

The shelducks must sharpen up their security skills.

It will be another month

before the ducklings are old enough to fend for themselves.

Cemaes Head in Pembrokeshire.

Local legend says that mermaids once lived beneath these vast twisted cliffs.

Today, it's a refuge for an animal often mistaken for a mermaid...

the grey seal.

SEALS WAIL

This pregnant female has come ashore to join the congregation.

They gather here for their annual spring moult.

It can take around six weeks

and they won't leave until they have their new waterproof coat.

During this time, the seals won't eat.

Their thick fur comes off in tufts.

It's an itchy process.

At such close quarters, it leads to some grumpy exchanges.

As soon as they have their new coats

the seals will return to solitary lives at sea to fatten up on fish.

The females must get into peak condition, as they'll be giving birth in the autumn.

Their fishing grounds lie beyond the cliffs in Cardigan Bay.

In Summer, large shoals of fish migrate inshore

and these attract the world's most charismatic marine mammal...

DOLPHINS WHISTLE

...bottlenose dolphins.

This is a group of mothers and youngsters.

The calves will stay with their mothers for several years learning to fish.

Bottlenose dolphins are highly sociable.

The group is in constant communication.

Each dolphin has its own unique signature whistle...

DOLPHINS WHISTLE

...and the Cardigan Bay dolphins may have their very own dialect.

Their whistles are at a higher frequency than those recorded

anywhere else in the world.

Foraging over, the dolphins' focus shifts to another favourite activity.

It's playtime.

A group of males have heard the excitement and come to investigate.

DOLPHINS CLICK

This gang of males are on the lookout for mates.

As they approach the females, they have a definite game plan...

rubbing and nuzzling their bodies in the art of seduction.

Eventually, one of the males wins the prize.

It's the first time this courtship behaviour has ever been captured in the bay.

Once this brief encounter is over, they go their separate ways

and the mothers and calves start the search for their next fish dinner.

BIRDS CAW

Back at South Stack

the guillemot parents now have a two-week-old chick.

CHICKS CHEEP

He's growing fast and has a huge appetite.

The parents alternate fishing trips.

It's Mum's turn.

Guillemots can travel up to 30 kilometres in search of the best shoals of fish.

She'll be away for several hours.

In the meantime, Dad must keep a close watch on his lively youngster.

It's a long way to fall.

To fish, Mum must keep her feathers in tip top condition.

Glands beneath her wings secrete a powerful waterproofing oil.

Like all guillemots, she's a surface diver

and hunts for shoals of small fish.

On a single breath of air, she can dive up to an astonishing 70 metres...

pursuing her prey in a high-speed chase.

Back on the cliff, the chick waits impatiently.

Mum finally returns.

BIRDS CAW

As soon as the youngster has had his fill, it's Dad's turn to head out.

In just under a week, the whole family will abandon the cliff

for the sea.

For now, Mum keeps her chick firmly under her wing.

Throughout the summer months

the long days and calm seas attract thousands of migrant birds.

Suspended in the gentle sea breezes, paragliders join in the aerial dance.

Arctic terns fly in on the winds.

They're here to breed before heading south to Antarctica.

The longest migration of any bird.

As night falls, the sea shimmers with mysterious flashes of fluorescent light.

These magical displays are created by blooms of plankton

emitting tiny photons of light.

But the most powerful force influencing the coast...

is the moon.

Twice a day, as it revolves around the Earth, the seas rise and fall

creating an ever-changing tidal landscape.

As the sea retreats in Fishguard Bay, a magical kingdom appears.

Rockpools.

With time sped up

these seemingly tranquil oases are bursting with life.

A bustling metropolis.

As the tide comes and goes, hidden dramas are played out here.

Surprisingly, starfish are the apex predators.

They use their powerful sense of smell to hunt down their favourite food

mussels and clams

prising open the shells with their suckers.

Then they extend their stomachs out of their mouths

and over the hapless prey.

For those lower down the food chain, competition is fierce.

The common blenny.

Only 16 centimetres long, it's a determined little fish.

This rockpool is home.

He will wait out the falling tide here and nowhere else.

As well as providing shelter, it's full of delicious titbits.

Across the pool, this common prawn is also on the lookout for a midday snack.

It doesn't go unnoticed.

The snail's tough conical shell presents a challenge...

so the prawn enlists some help from his friends.

The blenny watches them hard at work.

Now he joins the fray and hustles to the front.

But the prawns aren't giving up without a fight.

Success...

or maybe not.

Better luck next time.

BIRDS CAW

Today is one of the biggest tides of the year.

ENGINE WHIRS

Burry Inlet in Gower has one of the largest tidal ranges in the world.

Beneath the shifting sands and mudflats lie hidden gems.

Treasure that's highly sought after by both wildlife and people.

Cockles.

Generations have made a living from this seaside larder.

A skilled cockleman can harvest thousands in a day.

OYSTERCATCHER CHEEPS

Cockles are also the favourite fare of oystercatchers...

but they can only extract the cockles one at atime.

With no helping hands, there's a lot of skill involved.

They use the tip of their sensitive bills to detect hidden prey.

The stout beaks are the perfect tool to extract them from the sand.

Whelks are another firm favourite.

And worm casts provide another tasty morsel...

lugworms.

Oystercatchers are picky eaters.

They don't want any sand spoiling their rich seafood platter.

It's hard work but well worth the effort.

Down in one.

On a big spring tide, the sea will recede for up to 13 km

and these extreme low tides

can reveal tantalising glimpses of lost landscapes.

Ynyslas Beach on the Dyfi Estuary.

As the sea retreats, strange shapes emerge from the sand.

This is a petrified forest that dates back 4,500 years.

It's thought to have inspired the legend of Cantre'r Gwaelod

a mythical sunken kingdom.

The Lost Atlantis of Wales.

It's said that if you listen closely

you can hear the church bells ring out from under the waves.

BELLS CHIME

These ancient, fossilised forests remind us

of how the coastline has changed over time

and how the sea can reclaim us all.

BIRDS CAW - DOG BARKS

Back at Fishguard, time is running out for the inhabitants of the rockpool.

DOG BARKS

As the sea retreats further

these rocky refuges turn into potential death traps.

The blenny is now a fish out of water

but nothing is going to budge him from his home.

Incredibly, he's still alive.

As long as he stays moist, he can breathe through his skin.

As the rockpool dries out, he needs to find shelter.

He has to move fast, there are beady eyes on the lookout.

SEAGULL CRIES

The beachgoers are oblivious to the life and death drama playing out nearby.

The blenny has found a damp crevice to wait for the tide

but even this is about to dry out.

There are several hours to go before the sea returns.

The blenny's strong attachment to home could cost him his life.

DOG BARKS

SEABIRDS CRY

The tide returns just in time.

Safe until the next full moon.

It's late summer in the estuary.

This year's youngsters are starting the next chapter in their lives.

All three shelducklings have survived and reached adolescence.

Their parents have now left them to fend for themselves.

At Mumbles Pier, beneath the old lifeboat station

kittiwake fledglings are about to leave home.

True oceanic birds, they will travel far across the Atlantic.

For other young animals the move between the different worlds of land and sea

presents a huge challenge.

On an isolated Pembrokeshire beach...

baby seals have been born.

SEAL PUP CRIES

SEAL PUP CRIES

This pup is only four days old and still has her umbilical cord.

Her thick fur coat helps her keep warm.

The white colour is a relic from the last Ice Age.

She's entirely dependent on her mother.

For the first three weeks of life, she suckles five to six times a day.

The summer feeding has paid off for Mum.

Now she will lose a third of her body weight.

Thanks to this super rich milkshake, the pup will gain

nearly four and a half pounds of weight each day.

Within three weeks, she should have tripled her birth weight.

But even the best mums need to take a break.

SEAL CRIES

Time for a snooze.

Like all seals, the young pup has a Curious nature.

With mum asleep, she has an opportunity to explore.

The rocky beach is a fabulous adventure playground...

but it's not without risk for such a small pup.

This washed-up fishing gear is definitely best avoided.

SEAL PUP CRIES

One of the older pups is already out and about enjoying a quick dip.

This three—week-old youngster already weighs over 50 kilos.

He's shed his baby fur and now sports a shiny new diving suit

but he still needs to develop his swimming skills.

A piece of seaweed provides the perfect training tool.

She can't resist joining the bigger pup...

SEAL PUP CRIES

but she's far too small to take on the rough surf.

Her fur coat only keeps her warm when dry.

Once wet, it becomes heavy and drags her underwater.

SEAL PUP CRIES OUT

If Mum doesn't come soon, the pup may drown, become hypothermic

or be smashed against the rocks.

SEAL PUP CRIES OUT

She calls out for help.

Mother puts herself between the pup and the breaking waves.

Safe.

SEAL PUP CRIES

It's an important lesson for the youngster.

In just a couple of weeks, her mother will leave her

to return to the sea.

She has a lot of growing up to do before she takes on the might

of the Celtic Deep.

It's dusk at South Stack.

CHICK CRIES —- The guillemot chick

is finally ready to leave the cliff and head to sea

but it's a daunting moment.

This is a life—or—death decision.

The drop to the sea is a sheer 70 metres.

At the foot of the cliff lies a series of jagged rocks.

The chick's wing feathers are still not fully formed.

So, this is a true leap of faith.

BIRD CAWS — Dad leads the way.

BIRD CAWS — He calls up for encouragement.

Mum coaxes from behind.

He doesn't want to be first.

Another chick takes the plunge.

BIRD CAWS

Perfect execution.

BIRDS WARBLE

Another jumps.

Not so lucky.

RAVEN CAWS

The ravens snaffle up the chicks that fall short.

It's now or never.

CHICKS SCREECH

He's short.

RAVENS CAW

But miraculously, he survives.

He must be quick.

He won't be safe until he reaches the sea.

Spotting the danger, Dad races to help.

There's not a moment to lose.

RAVENS CAW —- BIRDS SCREECH

Together again.

A few more jumps...

and he's made it.

The first giant step to his new life

out at sea.

He will now spend the next few weeks with Mum and Dad learning how to fish.

The young guillemot won't return to land for another two years.

All around the Welsh coastline, the young are growing up...

starting to venture into the shallow seas beyond.

Here they will encounter a very different world.

They will need all their ingenuity and courage

as they head further into the Celtic Deep.