New Zealand: Earth's Mythical Islands

In the far reaches of the Pacific Ocean...

...lies a land cut off from the rest of the world...

...since the time of the dinosaurs.

After 80 million years of isolation,

nature has gone its own way.

In this lost world, life plays by different rules.

Penguins in the forests...

...parrots in the snow...

...and predators from prehistory.

Their lives are dominated by the most powerful forces on Earth.

When humans finally arrived, they discovered

nowhere is more strange and mysterious than New Zealand.

There are more species of penguin in New Zealand

than anywhere else in the world.

They first evolved here around 60 million years ago.

And here, in their ancestral home,

the penguins do things a little differently.

This Snares penguin has been out with hundreds of others

catching fish for her chick.

Like all parents here, her commute home to feed him is unusual.

She follows a path worn by thousands of tiny feet.

Next, a sheer rock face.

When you have no arms and a swimmer's body,

it's a bit like scaling a slope in a sack.

One obstacle conquered, now it's on to the next.

An expedition into the woods.

Hidden deep amongst the gnarled trunks and ferns,

they've established a large woodland colony.

Mum may have scaled cliffs and battled through forest

but she's not home yet.

She's just one of the 60,000 residents who make this journey.

Over centuries, they have worn down a maze of tiny streets

and miles of crisscrossed pathways.

She has to remember every twist and turn...

...while jostling past all the other busy commuters.

Finally, she reaches her destination,

half a mile or so inland.

One of many forest clearings where penguins have their young.

Her partner and her baby are waiting for her,

if she can find them.

Other adults are very protective of their territory.

So returning penguins hold themselves in a peculiar posture

designed to intimidate.

Home at last.

And Mum finally delivers a meal of pre-digested krill.

This woodland lifestyle is only possible for a sea bird

due to one remarkable fact.

New Zealand doesn't have any large predators -

in fact it never had any large land mammals at all.

The reason lies back in the time of the dinosaurs,

when New Zealand was one small part of a single gigantic continent.

Around 80 million years ago, huge geological forces broke up the land.

One fragment was forced far out into the ocean.

New Zealand -

cut-off and impossible for any land animal to reach since.

The same geological forces that caused its isolation

are still alive today.

In this part of the North Island, the ground water boils.

The Pohutu geyser, New Zealand's mightiest...

...erupting up to 20 times a day,

shooting super-heated water 30 metres into the air.

The geysers form part of a dramatic geothermal landscape.

With boiling cauldrons

and corrosive lakes with scalding water.

It's so acidic that it dissolves the rock itself...

...into a mineral slurry.

Hundreds of steaming vents breathe eerie life

into this deadly landscape.

At its heart, Frying Pan Lake, one of the world's largest hot springs.

The water here is hot enough to slowly cook your flesh.

As it flows downhill, it cools and deposits colourful minerals.

Over thousands of years,

these build up into glistening crystalline terraces.

Further downstream, the water cools to around 40 degrees,

the temperature of a steaming hot bath.

It's too hot for fish,

so the stream beds are largely predator-free.

A haven for heat-tolerant insects.

Wisps of geothermal midges.

They only fly a day or two so they urgently dance in search of a mate.

But their performance attracts unwelcome attention.

A mob of fantails, one of New Zealand's smallest

and most agile birds.

It's easy to see how they got their name.

This father has a ravenous family to support.

His hunting technique is called hawking.

He leaps from stream-side perches to snatch the midges in midair.

A fantail's flight isn't just fast, it's unpredictable, too.

Slowed down 20 times, the secrets of this aerobatic ace are revealed.

Short, round wings give him the power and manoeuvrability...

...of a stunt plane.

But it's his enormous tail that gives him the edge.

Fanning it out turns it into a giant airbrake,

creating the equivalent of a handbrake turn.

The midges are tiny, so to feed his growing chicks,

this dutiful dad undertakes more than 300 sorties an hour.

These fantails have turned this uninhabitable landscape

into an opportunity.

In New Zealand, hostile environments are part of everyday life.

The entire country sits astride a massive tectonic plate boundary,

where two shifting fragments of the earth's crust meet.

Just off the coast of Kaikoura,

this boundary takes the form of an underwater canyon,

a trench that brings the deep sea near to the shore.

The depths of the ocean are full of nutrients and here,

close to the coast, winds and currents force them to the surface,

creating a rich feeding ground.

Bull sperm whales come to bulk up on deep-sea squid.

And there's plenty of prey for their smaller, more agile cousins.

Dusky dolphins live here in their thousands.

All dolphins communicate with each other using a complex range

of underwater sounds and clicks,

but Dusky dolphins can speak in another way, too.

As a species, they are some of the most

acrobatic dolphins in the world, and researchers have discovered

that leaping is part of their communication.

Some jumps and splashes may have their own particular meaning.

A high leap and a clean re-entry can be a signal there are fish below.

A jump and a sharp tail slap is loud and far-reaching underwater,

so may help coordinate large pods.

It appears to be one of the easier moves,

and youngsters are keen to learn.

Mum shows him how an expert does it...

...and now it's baby's turn.

Young dolphins can stay with their mothers for up to three years,

so they get plenty of time to practise.

Synchronised leaping is more difficult to master.

Leaping may encourage dolphins to work together,

a vital skill for rounding up fish.

But the most spectacular jump and perhaps the hardest to master...

...is the acrobatic leap.

This one may be just for fun.

On the land beyond the Kaikoura coast, the shifting plates

which drive the canyon downwards now thrust the land upwards.

This creates a mighty chain of mountains

which form the spectacular backbone of the South Island.

The Southern Alps -

New Zealand's greatest wilderness.

Reaching almost 4,000 metres,

the mountains are still growing...

...despite the weight of some 3,000 glaciers slowly grinding them down.

This is New Zealand's most challenging terrain

with a climate to match.

Animals have to be tough and resourceful to survive here.

Sheep were introduced to New Zealand over 200 years ago.

With expert help, they can live in even the most extreme conditions.

But farmers must adapt to the violent swings of alpine weather,

and know when to act.

For sheep farmer Kate Cox,

protecting her precious flock is an extreme challenge.

So the property here's about 40,000 hectares, which is pretty big.

It stretches from the lake right through the mountains behind us,

through a couple of ranges of mountains.

So it would take maybe a couple of days to walk across it.

This is one of the biggest days in Kate's calendar.

Hey, girls. Are you excited?

The autumn sheep muster.

Good girl. Sit down. So basically an autumn muster...

They've been going on for about the last 150 years on this property,

and really all it entails is bringing down the sheep

from all the high summer's grazing in the mountain tops,

and bringing them down to lower levels

where they're gonna be safe from snow during the winter.

For more than 100 years, the muster would have meant two days

of hard hiking. But Kate's team of shepherds have a helping hand -

a helicopter and some of the very few flying sheepdogs in the world.

Their goal today is to muster at least 4,000 sheep if they can.

Her brother Davie is the pilot.

Their family have been working these hills for 40 years.

Even for farming in New Zealand, this isn't your normal farming.

It's in the, you know, the

harshest environments that you can farm in New Zealand.

So yeah, it's a bit on the edge.

Right.

Kate has 29,000 merino sheep up here,

one of the very few breeds tough enough to survive.

But the winters are severe and too many would die in heavy snows

if they were left to roam all year round.

Today, Kate's team consists of five shepherds and ten dogs.

I'll head down that track to the grain.

Yep. just come with me...

The tactic is to start at the very top,

looking for the most adventurous sheep.

So up on the tops of the mountains, it's quite rugged.

A lot of rock, cliffs and a bit challenging at times.

A good rule of thumb is if your dogs don't want to follow you,

you shouldn't be going there either.

Have you just popped out on that ridgeline?

Can I see you up there?

Yeah, we are out on the ridgeline, but there's a bit of fog coming through.

You need to be able to look after yourself, look after your dogs,

and look after the stock, because, generally,

like, no one's coming to help you.

The first sheep are soon flushed down from the high slopes.

Here's a mob coming down as well.

Kate and her dogs, Fudge and Fred, must intercept them.

We have a huntaway, which is a New Zealand breed,

which has got a bit of all sorts of things in it.

And they generally are big, noisy, rambunctious.

You're such a showboat, Fudge.