01x06 - Stewart Island

[bunniefuu]

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[water splashing]

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Narrator: Spring brings longer days

and spectacular twilights to the southernmost part

of New Zealand.

Stewart Island or Rakiura, the Land of Glowing Skies.

[birds screeching and water splashing]

All around the coastline, the island's iconic animals

are coming together to breed and feed.

Out in the deep ocean and the many sheltered inlets

and on the beaches,

every day is a struggle to find enough food

for hungry mouths

and to stay alive.

[water splashing]

[creatures crooning]

As twilight fades, this male southern brown kiwi

has only one thing on his mind, food.

He's five years old.

And this is just his second breeding season.

All day he's been sitting on the single egg

his mate has laid and now he's ravenous.

What he does next is unique among kiwis

which live in New Zealand's forests.

He heads to the beach.

It's a mystery when and why these coastal kiwis

added seafood to their diet.

But the sand hoppers and small invertebrates

buried in the sand are now vital to this male's survival.

There's one drawback when beachcombing.

Kiwis are the only bird with nostrils

at the end of their beak, perfect for sniffing out food

beneath the forest floor.

But they haven't yet evolved to cope with sand.

By the time this young male calls it a night,

the day shift on Stewart Island is waking up.

This little blue penguin pair has spent the night together

in their nest burrow,

both keeping their precious eggs warm

during the cool of night.

It's common for mates to preen each other.

It's likely they'll stay together

for the rest of their lives, up to 25 years.

It's the male's turn to go fishing today.

Little blues are the world's smallest penguin,

standing 30 centimeters tall and weighing just one kilogram.

But the little bird has a big responsibility.

If he doesn't make it home from the sea,

the female won't be able to raise their chicks alone.

So it's not just his life on the line.

Every time he goes to hunt, he runs a gauntlet

of hungry predators.

[water splashing]

Home for all these creatures is sculpted

in a myriad of ways by the sea.

Huge swells roll off the southern ocean

to batter exposed rocky coasts.

Wild westerly winds carry beach sand

three kilometers inland at Mason Bay,

creating a vast expanse of dunes.

At Paterson Inlet, the sea has invaded the land.


bush-clad valleys here.

Today, it's a maze of sheltered inlets

where pristine native forest still grows

right down to sea level.

And beneath the surface, the forest continues.


The most spectacular is the giant bladder kelp

that towers up from the sea floor.

Gas-filled bladders keep the kelp upright,

facing the energy-giving sun.

Kelp photosynthesize just as plants do.

But that's where the similarity ends.

These holdfasts are not roots.

They're merely an anchor against storm and tide.

The kelp absorbs all its nutrients from the currents,

through its flat blades.

All around Stewart Island, nutrient-rich currents

from Antarctica converge with warmer waters from the north,

creating a vast upwelling of food,

which attracts a multitude of animals,

both year-round residents and regular visitors.

[water splashing]

[inspiring music]

Near the kelp forest floor,

this pair of pot-bellied seahorses is courting.

They're normally solitary creatures,

each with its own territory,

but spring brings them together to mate and breed.

When they're not dancing, they grip the kelp

with their tails to avoid being swept away

in the strong current.

They swim only in short bursts, fluttering their dorsal fin

up to 40 times a second

as they steer with the small fins on the side of their head.

[inspiring music]

Once their courtship is complete, in a bizarre twist

it's the male who carries the fertilized eggs

in a special pouch for a month

and then gives birth to up to 1,000 live young.

The offspring disperse immediately.

With no protection from parents, only one in 1,000

will survive to adulthood.

[dramatic music]

As many predatory fish patrol the forest,

it helps to have eyes that move independently.

They can eat and keep an eye out

for danger at the same time.

But camouflage in the kelp forest is their best defense.

The male penguin could be a threat.

If the fishing is poor, little blues will hunt for crabs

and seahorses on the seabed.

But luckily for the seahorse family,

the male is passing through as fast as he can.

He's detected the presence of one of his main predators,

a New Zealand sea lion.

This juvenile male can't yet challenge the bulls

that have recently started breeding on Stewart Island,

which leaves him time to inspect

the kelp forest for anything edible.

And penguins are definitely on his menu.

Just like seahorses, the penguin relies on camouflage.

He's white below and blue on top,

which makes him hard to see from above and from below,

which is critical because his top speed

is just six kilometers an hour.

Just when he seems to have eluded one predator,

another spots the penguin.

This four-meter-long great white shark

often cruises around Paterson Inlet

at a top speed of 40 kilometers an hour.

And he's not fooled by the penguin's camouflage colors.

Hundreds of tiny black dots on his snout

can detect the bird's faint electrical signature.

[water splashing]

Luckily for the penguin, a one-ton shark won't bother

expending too much energy chasing a one-kilogram penguin,

which equates to a mere snack.

All around the Stewart Island coastline,

dozens of other small islands are scattered.

Sheer vertical cliffs mean these islands

are inaccessible to many of the locals.

But that makes them a perfect home

for literally millions of these birds.

Collectively, the islands are known

as the Muttonbird Islands, named after the birds,

which are also called sooty shearwaters.

[birds screeching]

[water splashing]

Unlike penguins and kiwi,

these seabirds are not permanent residents.

Every autumn they set off on one of the most

spectacular migrations on the planet,

roaming as far away as Alaska during the southern winter.

They can travel up to 75,000 kilometers on this journey

and average more than 500 kilometers a day.

But every spring they return to these same islands to breed.

They arrive about the same time as another ocean wanderer

which always returns to this neighborhood.

But the shearwaters are so distracted

they don't take much notice of a great white shark.

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Huge swarms of krill are one reason

seabirds flock here year after year.

The tiny crustaceans drift just below the surface

and are easy pickings for a shearwater,

which can fly almost as well below the water as above it.

These birds can chase fish to depths of up to 70 meters,

second only to penguins in underwater swimming ability.

Sooty shearwaters' feathers are so well waterproofed

with oils that after a dive, they pop back to the surface

almost bone-dry and ready to fly.

Or plunge straight back down.

[water splashing]

Chasing a flock of frenzied birds

is not a priority for this shark.

But Stewart Island's great whites

are notoriously aggressive.

[water splashing]

And a shearwater snack is better than nothing.

At least 82 great white sharks share the waters

around Stewart Island.

But like sooty shearwaters,

these sharks leave the neighborhood during winter

to take a holiday in warmer waters.

They travel as far away as Fiji and Tonga

and then return to the exact spot around Stewart Island

where they were originally tagged.

These great white creatures of habit

also pick up hitchhikers on their travels.

This pilot fish has accompanied the shark

all the way from the tropics.

It gets protection from predators and scraps of food

and repays by picking parasites off the shark.

Sometimes the top of the food chain

can get a little crowded.

But great white sharks have a loose social hierarchy,

where big fish generally give way to even bigger fish.

Tail-wagging and pointing pectoral fins down

are a warning to the other shark to back off.

[water splashing]

The scars on this four-meter male

show what happens when warnings are ignored.

Back in the sheltered waters of Paterson Inlet,

the male blue penguin has joined

a small group of fellow hunters.

They can hold their breath for up to two minutes

and dive to 60 meters.

But the majority of dives are much shorter,

around 20 seconds and less than two meters

below the surface.

When the fishing is good, there's no need

to expend more energy.

At the end of a hunt, the penguins will often come together

in a group, known as a raft, as they contemplate

the safest way to get ashore.

The thick native forest, which covers parts

of Stewart Island right down to the shoreline,

has a profound effect on the sea life

in these sheltered inlets.

The rivers that run off into the sea are filtered

through the root systems and so the inlet is silt-free.

Even the bare sea floor beyond the kelp forest

is a healthy ecosystem inhabited by truly bizarre creatures.

Sea cucumbers burrow in the sand,

using feathery tentacles to trap floating morsels of food

to feed their hungry mouths.

Nearby, one of the sea cucumbers' relatives

st*lks what looks like a common sea snail,

a favorite meal of the 11-armed starfish.

The starfish positions itself to eject its stomach

inside the shell to eat the contents,

when suddenly the tenant appears.

It's a hermit crab.

To avoid becoming crab soup for the starfish,

it makes its escape,

with its home on its back.

Crabs are resourceful with their protection,

whether it's a borrowed home,

a hard shell,

or camouflage

because everyone loves to eat them down here.

And none more so than the common octopus.

The resident female has woken up to hunt.

But for her too the sea floor

is a dangerous place to be exposed.

Sharks, sea lions, and even her own kind

all see her as a meal.

Like so many of her neighbors,

camouflage is her first line of defense.

But she takes it to a whole new level,

changing the color of special pigment cells in her skin,

while other cells mirror the color of her surroundings.

She can also change the texture of her skin.

All this in less than a second.

When the coast is clear, she jets forward

in her search for crab.

Octopus are highly territorial, so when she spies

an intruder under a rock, she's ready to fight.

But the intruder attacks first.

[water splashing]

Octopus saliva contains deadly venom

which kills their prey but has no effect on their own kind.

The intruder is bigger and smothers the resident female,

claiming this territory for now.

Cannibalism in the octopus world is common

and nothing will go to waste.

Above the surface, the day draws to a close.

It's time for the shearwaters to head back to their islands.

Their wings and bodies are designed

for long-distance flying, not quick takeoffs and landings.

And they need a long run-up to get airborne.

[water splashing]

Soon, tens of thousands of birds

circle the Muttonbird Islands.

with dense forest below, breaking through the canopy

to land seems like mission impossible

here on the southernmost tip of New Zealand.

As spring edges towards summer, twilight in the deep south

can last until 10 at night.

But sooner or later, these sooty shearwaters

returning from their day's fishing at sea

must come down to earth.

With their bodies built for long-distance flying,

maneuvering into land is an awkward process.

Basically, it's a crash landing.

And they have to do this every day.

Soon, shearwaters are plunging

through the canopy all over the island.

It takes them a moment to get their bearings

before they head for home, no worse for wear.

Sooty shearwaters nest in a maze

of underground tunnels, which they dig themselves,

well-insulated from temperature extremes.

This pair rekindles their bond.

They may have spent the year as far apart as Alaska

and Japan before reuniting to breed again.

They'll probably keep meeting here in the same borough

to raise chicks together for another 15 years.

Little blue penguins often come ashore for the night

in a group, as there's safety in numbers.

[inspiring music]

Like all penguins, little blues are ungainly on land.

And easily spooked.

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The penguins know a lone seal is no threat on land.

But they're still cautious as they tiptoe around him.

His belly full from a good day's fishing, the male penguin

is greeted by his mate with great enthusiasm.

Tomorrow, he'll stay on the eggs while she goes to sea.

It's been 30 days so far and the eggs

could hatch any day now.

Soon there'll be extra mouths to feed

and a lot more fish to catch.

Nearby, the kiwis' borough

is a stone's throw from the penguins.

[inspiring music]

The kiwis' nest is also constantly tended.

But in a unique twist, this bird is not one of the parents.

She's the couple's chick from last year.

She won't breed for at least three more years

so she helps out at home with about 20%

of the egg incubating.

Amongst New Zealand's kiwi species,

it's only the Stewart Island birds

that live in these family groups,

with older offspring helping out.

It's a behavior they may have evolved during an ice age

when the deep south was much colder

and the birds needed to huddle together for warmth.

With a helper on the nest, the female kiwi

takes the opportunity to forage in bush nearby.

The nights at this time of year are so short,

she often forages until well after dawn,

while the male minds the nest.

But she usually stays clear of the busy beach

at this time of day.

These oyster catchers live together peacefully

during the winter months.

But now that it's the breeding season,

they're highly territorial.

An eastern curlew has flown halfway around the world

to escape winter in Siberia.

It'll stay until March, fattening up on crabs

to fuel it for the long flight home.

[water splashing]

Below the surface,

the intruder octopus is also hunting crabs

in his new territory.

A paddle crab can attempt to swim away.

But its escape tactics are no match

for the hunting skill of an octopus.

It's almost as if he's playing with the crab.

[dramatic music]

He injects venom to immobilize

and enzymes that liquefy the crab's flesh

so he can suck it out and feast.

The octopus's efforts attract the attention

of the blue cod g*ng that rules this neighborhood.

Cod don't have a swim bladder,

which is a gas-filled organ that helps control buoyancy

in many species of fish.

Instead, they stand over the seabed,

rarely straying more than a kilometer

from where they were born.

The largest cod in this g*ng are males,

which can live to be 30 years old.

Blue cod eat anything that moves

and some things that don't.

A clump of mussels broken loose

from the rocks is a challenge.

But blue cod jaws are powerful.

Perseverance pays off for the aggressive males.

And the spotted wrasse, which scavenges for scraps

but could become cod food at any time.

[water splashing]

In a remote bay on the Stewart Island coastline,

the little blue penguin mates

are about to become parents again.

For 37 days, they've taken turns to run the gauntlet

of predators to return to their nest.

One chick hatched and another on the way.

Only one in five little blue chicks survive long enough

to become an adult and breed.

Most die soon after leaving the safety of the nest.

But these chicks' chances are better than average.

Their unique island home is free from stoats and ferrets.

For the parents, with two new beaks to feed,

life now becomes busier than ever.

Today, it's the mother's turn to run the gauntlet.

[dramatic music]

For the inhabitants of the sea floor,

every day is a struggle of life and death.

The octopus is hunting crabs again.

But this time, as he leaves the safety of the forest,

he's ambushed by the blue cod g*ng.

A large male cod attempts to death roll the octopus.

In defense, the octopus unleashes a cloud

of ink and escapes.

But he's minus the tip of his arm and with that,

he's lost a few million brain cells,

as two-thirds of the octopus's neurons

are located in their arms.

He'll regrow his arm over the next few months,

another one of his species' amazing survival techniques.

On the ocean floor nearby, distant cousins of the octopus

watch the drama unfold.

Scallops cautiously open up

and take a look around with 100 eyes.

Unlike the octopus's keen eyesight,

the scallop's primitive eyes can just make out shapes

and patterns of darkened light.

So when the shadow of a predator passes, the scallop reacts.

A scallop's arch-nemesis is the super-stealthy


The slow approach improves its chances. No sudden shadows.

It's a textbook hunt.

But the scallop has one more trick up its mantle.

[water splashing]

It can swim, just a few meters at a time,

which is a short-term solution.

The starfish may be slow but it can crawl


which are also sensitive odor detectors.

If the tubes on the tip of an arm pick up a scallop's scent,

that's the direction the starfish will head in.

In the kelp forest, the female seahorse is hunting too.

The mating season is finished and the male has departed.

However, one of their offspring

is feeding in the kelp nearby.

His hundreds of siblings were dispersed by the currents

and it's just coincidence that he remained here.

He's now a few weeks old and won't be tolerated

in his mother's territory for long,

as she has no maternal instincts.

The youngster was born knowing what to do:

eat anything small enough to suck up.

And if it's too big, best leave that for the adults.

The female seahorse uses excellent color vision

to line up her prey.

Despite the name, a pot-bellied seahorse

has no stomach with which to digest food.

She extracts so little nutrition from each tiny shrimp

that she must continuously hoover them up.

In 1/300th of a second, another shrimp

starts its journey down her gut, alive.

Back on the barren sand, the scallop faces

a much slower death.

The starfish has caught up and this time

it's not letting go.

The scallop has no more defenses, just 100 eyes

with which to watch the nightmare unfold.

The spottys gather like vultures

as the starfish begins to eat the scallop alive.

In the sea, there's always someone

higher up the food chain than you.

These little blue penguins now have hungry chicks to feed.

So in an instant, the tables turn

and the spottys flee into the kelp.

But these deft little underwater hunters

know how to pick them off, one by one.

[birds calling]

Early morning over Stewart Island and it's time

for the morning commute to the fishing grounds.

[birds scrambling]

For the sooty shearwaters, the march through the forest

is one long traffic jam.

[birds calling]

With their eggs laid deep in their burrows,

the mated pairs will take it in turns to fish daily at sea.

It's impossible for these birds to take off

from the forest floor with the canopy of trees above.

So it's an hour's waddle to the nearest clifftop launchpad.

[birds calling]

It's a good day on the water, with swarms of krill

and small school fish just offshore,

which the birds can see from above.

Sooty shearwaters descend in their thousands,

along with seagulls.

Soon an all-out feeding frenzy is underway.

[water splashing]

[dramatic music]

Now, white-capped mollymawks join the fray,

slightly smaller cousins of the giant albatross.

These majestic birds have a wingspan

of two and a half meters and need an even longer runway

than the shearwaters.

Then it's time to size up the opportunities below.

Unlike the diving shearwaters,

mollymawks are usually surface-feeders, catching fish,

krill, and squid just below the waves.

But there's always one exception to the rule.

All this commotion attracts the attention

of other Stewart Island residents.

A great white shark arrives right on cue.

He's not here for moon jellies or any small fish.

He's hoping other predators will be attracted

to this feeding frenzy.

It could be three weeks since his last meal,

probably a nice, fat fur seal.

[birds screeching]

Now it's time for him to eat again.

So far, nothing but seabirds.

Then a second shark arrives to investigate.

Still, the seabirds don't perceive any threat.

But the sharks are growing tired

of waiting for a decent meal.

This bird is dicing with death.

She saw the first shark just in time.

But she wasn't expecting this.

When this bird breeds, she'll be passing on genes

for incredible luck.

[water splashing]

Back on land, there's activity in one of the burrows.

Just up from the beach, the kiwi family

is about to grow a little bigger.

It's taken three months of dedicated incubation

by the entire family.

The egg is so enormous because the chick emerges

fully developed, attached to an internal yolk sack,

which fills the hatchling's little pot belly.

This provides immediate food

and can sustain it up to 17 days.

All kiwi chicks are on their own as soon as they hatch.

But this unique Stewart Island chick may spend

up to seven years living in the family unit

and help to incubate future generations.

By contrast, the penguin chicks are completely dependent

on their parents for food.

[dramatic music]

They've been fed constantly for four weeks

and now weigh almost as much as their parents.

From now on, the chicks will be left alone during the day

while both parents fish to meet their appetites.

In three more weeks, they'll instinctively head

to sea themselves.

Then they too will have to run the gauntlet

of sea lions and sharks and take their chances

in this unique, southern, big blue backyard.

[inspiring music]

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