[Underwater bubbling] [Whale song] Narrator: In warm tropical waters, a tiny giant is finding her fins under the watchful eye of her mother, a 40-ton humpback whale.

[Whale song] ♪ She's only 3 weeks old, and she's lucky enough to have been born off the most pristine tropical coastline on the planet.

♪ When this little bubba's strong enough, she'll join one of the largest populations of her kind, who come every year to the Kimberley.

[Whale song] ♪ ♪ [Thunder roaring] [Fire crackling] ♪ [Thunder roaring and cracking] ♪ [Hissing] ♪ [Birds calling] ♪ The Kimberley is unique on our planet.

A tropical wilderness that spans over 150,000 square miles of northwestern Australia.

An area almost the size of California.

This is a land defined by its extremes... ♪ a wild climate, harsh terrain, and remarkable biodiversity... ♪ with species found nowhere else on Earth.

[Clicking and squeaking] But this is more than a wilderness.

This is a human landscape, home to the oldest living culture on Earth.

For First Nations people, this land is more than just our home, it's a living, breathing entity.

We call it Country, and we've cared for it for over 50,000 years.

But the Kimberley is now facing threats from near and far, and these new challenges are making life for the animals here even tougher.

♪ [Bird chirping] Following their wild lives through 6 intense tropical seasons, this is the story of a year in one of Earth's last great tropical wildlands.

♪ [Growling] [Insects chirping] [Thunder rumbling] The wet season, or Wilakarra, is a time of renewal on Country.

[Thunder rumbling and cracking] The power of the monsoon turns the land into a labyrinth of raging rivers, waterfalls, and pristine creeks.

But when the rain finally stops, our arid landscape is transformed.

♪ This is the season of Koolawa.

["Kalaji-Rai" by Mark Coles Smith playing] ♪ And all this time I see the water ♪ ♪ And this life ♪ ♪ Running through the sand ♪ Narrator: The annual pulse of rain is the heartbeat that brings Country to life.

♪ In the season of Koolawa, rivers become arteries and veins that bridge vast distances across our landscape.

[Birds squawking] ♪ For many young male crocodiles, it's time to make some big life choices.

It can be hard to find your place in the world as a teenager.

Competition for food and females on the river is fierce.

[Growling] And the best territories are controlled by "Boss Crocs."

These kings of the river can be well over 40 years old and reach over 6 meters in length.

They wouldn't hesitate to kill a 3-meter teenager.

♪ Even an accidental encounter could turn deadly.

♪ [Growling] ♪ Rather than fighting with their elders, the smartest ones go with the flow and follow the river through to the sea.

Those brave enough to leave home discover an expansive coastline teeming with vulnerable and delicious life.

♪ And some of that life has traveled a lot further than the crocs to visit our coastline.

Roebuck Bay, in Yawuru Country, attracts some of the Kimberley's most devoted international visitors.

♪ [Birds chirping] Over 100,000 migratory shorebirds fly across the planet to spend the summer with us.

Many from as far away as the high Arctic.

♪ Around 30 species make the annual pilgrimage.

It's the shorebird capital of Australia.

[Birds calling] ♪ At high tide, the beach gets pretty crowded.

But these birds aren't here to work on their tan.

They're waiting for some of the largest tides on Earth to reveal Roebuck Bay's main attraction, 160,000 square kilometers of the richest intertidal mudflats on the planet.

Every square meter of this mud hides hundreds of different species and over a thousand animals.

It's the world's greatest all-you-can-eat bird buffet.

♪ One of the most delicious items on the menu is the Buggle Buggle.

At low tide, they emerge from their burrows to feed in the rich mud.

A fish unlike any other, mudskippers aren't confined to the water-- as long as they stay hydrated.

♪ They can even moisturize their eyeballs, making them one of the only fish that can wink.

In breeding season, these mudskippers show off their blue spots to attract the ladies.

♪ But good looks don't always get the girl.

And this female Buggle Buggle knows she's a high-value fish.

These two are gonna have to prove their worth in battle.

[Croaking] ♪ [Groaning] ♪ The loser slides back to his burrow, tail between his fins.

♪ But don't be ashamed, Buggle Buggle, there's plenty of fish in the sea if you can make it through the night.

[Thunder rumbling] For the Buggle Buggle, a full moon can be trouble-trouble, especially in Roebuck Bay.

When the birds go to bed, other creatures are just waking up.

♪ At night, a dangerous predator lies in wait.

The Roebuck Bay mangrove snake.

It's an ambush predator.

And tonight, mudskippers are on the menu.

♪ These snakes are triggered by movement.

♪ And the full moon has Buggle Buggle in the spotlight.

♪ Found nowhere else on Earth, the Roebuck Bay mangrove snake is unique to this one bay.

[Gulp] And thanks to the abundance of tasty mudskippers, there's nowhere else she'd rather be.

♪ [Birds calling] It takes a huge amount of food to feed 100,000 shorebirds.

And it all starts with tiny plants, invisible to the naked eye, that thrive in the rich mud.

♪ The plants are eaten by speck-sized animals, and up the food chain it goes.

As the tide recedes, an artwork that stretches the length of the beach begins to take shape.

♪ It's a sure sign that someone has been snacking on the micromorsels.

♪ Sand bubbler crabs pass the wet sand through their mouthparts, where they carefully extract plankton and other tidbits, before discarding the rest in neat little balls.

It's busy work at the bottom of the food chain, but at least these little artists aren't starving.

♪ Nature can be a complex thing... ♪ but if you sit and watch long enough, you will eventually see that us big things need the little things to survive.

♪ Hundreds of species and millions of individuals working together in this food web is what allows the huge flocks to feed and prepare for their long journey home.

[Birds calling] Since they arrived over 6 months ago, the shorebirds have undergone an extraordinary transformation.

♪ Some have doubled their weight.

They're now sporting richly colored breeding plumage.

Their heart and flight muscles have increased in size.

And while their bodies have changed, so too has Country.

♪ The shifting tides, the cooling temperatures, the passage of the moon and sun.

The season of Koolawa is coming to an end.

And as the air cools, the birds prepare for an unimaginable journey.

It's time for them to return to their breeding grounds.

♪ Their last days are spent cleaning and preening their feathers.

♪ To witness the first wingbeats of an epic journey like theirs is a rare privilege.

♪ Some will fly close to 10,000 kilometers non-stop all the way to the high Arctic.

♪ From the chaos of tens of thousands, they find their travel buddies and head north over the horizon.

[Birds calling] ♪ Somehow, they find their way over featureless oceans, through storms, and mountain ranges.

♪ Their story is proof that no life exists in isolation.

Every creature, every plant, every breath of wind is a reminder of how vast and interconnected the world we share truly is.

It's been a few months since the shorebirds left our coastline-- even longer since it last rained.

The cool dry season of Barrkana has arrived.

And just off the coast, a distinctive sound announces the return of one of our most cherished annual visitors.

♪ These humpback whales have just completed a 5,000-kilometer swim all the way from Antarctica.

[Whale songs] ♪ Some of them almost 11 months pregnant.

A long way to swim with a baby on board.

But it's a journey worth the effort, so that their calves can be raised in the stunning Sea Country of the Dambimangari people.

Ranger 1: Ranger 1, ranger 1, you got a copy there?

Where we off to?

Ranger 2: We're going straight down to Langy and then Slade Island.

Narrator: The Dambimangari Land and Sea Rangers look after more than 10,000 square kilometers of remote Sea Country.

But despite its isolation, it's now facing increasing threats from the outside world.

Destructive industries are looking to move into the area.

Illegal fishing operations are increasingly targeting these rich waters.

Introduced species and climate change now threaten many of their most precious animals.

♪ Facing down these threats is a monumental task.

But for Ranger Kallum Mungulu, it's more than just a job, it's a cultural responsibility.

Kallum: In Worrorra Country, all of the islands, out on the land, is significant to us.

They still hold a lot of our ancestors in them as well now.

Whether it's their spirit, or their bones.

♪ Our Country's not really been touched.

You know, you don't see much skyscrapers on our Country and whatever.

Narrator: On their week-long patrols, the rangers tend to thousands of significant sites.

And this Country is not only an incredible gallery of art and culture, it's the timeless resting place of their ancestors' spirits.

[Man singing in Indigenous language] ♪ Kallum: So it's good that it's preserved the way it is.

♪ Our old people always had that sense of caring for all of this.

Before they knew about science, I guess, they had that sense that they have to do it in order for all things to move and rotate perfectly in the world.

♪ Narrator: On their coastal missions, the Dambi Rangers navigate some exceptionally challenging waters.

Cyclonic storms ravage the region... [Thunder] and the largest tides in Australia can turn the ocean into a boiling mess of whirlpools and white water.

It's the complex and rugged nature of this Country that has helped safeguard it from outside interests.

Navigating these waters is all in a day's work for Azarnia Malay.

Azarnia: So, out here, as rangers, we monitor the reef, we monitor turtle, dugong, whales, even people.

Narrator: The rangers regularly work with scientists and conservation organizations to help study and protect the animals in their region.

Azarnia: Track up here.

Narrator: These islands are vital nesting sites for marine turtles, and the rangers come every year to conduct long-term population monitoring.

This is one of them that didn't make it.

So what we're gonna do is we're gonna get DNA from the flipper.

Narrator: Only 1 in every 1,000 sea turtles survives to adulthood in the wild.

And in this changing world, they need all the help they can get.

Ranger: Look at that, look at that.

He's still alive.

Oh, he's still alive.

This one's cute, hey?

We're here to save you.

[Chuckling] ♪ Azarnia: The old people had their own science.

Our people already knew all this.

And it's good for us to keep carrying on what our people used to do, but now we're doing it in a different way.

♪ Animal keep the Country alive.

Ranger: Come here.

Azarnia: Steady.

Watch out.

Yeah, give him a little private escort.

♪ Narrator: Thanks to the rangers, this little hatchling might have a chance.

Azarnia: Keep going, little buddy, you'll make it.

Ranger: He got it now, he got it.

My Liyan feel good.

♪ Sayonara, mate.

Swim!

Narrator: The cool season of Barrkana sees the arrival of many little ones.

[Cheeping] These baby ospreys are only a few days old, and they're utterly defenseless.

♪ But they are not alone in the world.

Their parents are powerful raptors.

♪ [Cheeping] And for the next few months, Mum and Dad will work together to keep these tiny chicks alive until they can fend for themselves.

[Squawking] ♪ [Cheeping] It's not easy to raise little ones out here.

Growing ospreys need a lot of food.

At least 6 meals a day.

And Mum and Dad work around the clock.

But they can't let their guard down.

Her bubbas are starting to look like a pretty good feed to some other predators in the area.

♪ A flock of reef egrets has taken an interest in the nest.

♪ These guys are notorious nest raiders.

♪ When Dad goes in search of food, the egrets close in.

♪ Mum's outnumbered.

♪ But she's not afraid of a few sticky beaks.

[Screeching] She takes the fight to them.

♪ And makes it clear who's boss.

♪ [Cheeping] But now, the chicks are on their own.

♪ [Osprey squawking] Dad makes it back just in time.

[Osprey calling] [Cheeping] ♪ Narrator: It's tough work being a parent, and it will be months before these chicks can fend for themselves.

But when they're ready, they'll soar off to make their home on one of the most beautiful coastlines on Earth.

The Dambimangari Land and Sea Rangers look after an area of more than 25,000 square kilometers.

The rugged terrain here has kept most threats from the modern world at bay.

But now, they are facing a new challenge-- the arrival of a toxic and invasive species.

Cane toads were introduced on the other side of the continent in the 1930s, and they have been spreading west ever since.

♪ These toads secrete a toxin that is deadly to any animal that tries to eat them.

♪ So their recent arrival in the Kimberley is a huge threat to the creatures that predate on frogs.

Including one of the Dambi people's most sacred creatures.

Wijingarri-- the northern quoll.

♪ Wijingarri was once common right across Northern Australia, but a combination of feral cats, poor fire management, and, now, the relentless spread of toxic cane toads has pushed these animals towards extinction.

[People chattering] For a long time, the Kimberley has been a safe haven for these cheeky marsupial predators.

But in the most recent surveys of northern quolls, their decline is catastrophic.

♪ It's a crushing loss for the Dambimangari people, who hold Wijingarri as a central figure in their creation stories.

Azarnia: It made me feel sad, real upset.

It's very important to us, the quoll, you know.

We don't want him to disappear.

♪ Without them, there's no Country.

We all need each other.

♪ Narrator: But all hope is not lost because Wijingarri has been here for a very long time.

And luckily, some places are harder for toads to reach.

Azarnia: So over the years we done a big survey of Dambi Country, we found out where most of the quolls live, and our main aim is trying to protect the islands.

Narrator: There are over a thousand islands on the Dambi coast, and 10,000 years ago, they were all part of the mainland.

For the lucky few who remained on the islands during the last sea level rise, the ocean now provides a protective barrier.

♪ The rangers regularly drop in to make sure the quoll population is happy and healthy.

[Insects chirping] Azarnia: We're going to put some camera traps out on the rocks where quolls live.

Narrator: The cameras offer a glimpse into who's living here and how many individuals there might be.

Once night falls, our little superstars arrive.

And they're not camera shy.

This frisky female is leaving her scent trail in full view.

And Young Fella has copped a whiff.

♪ Here on Quoll Island, contestants have lots of time to get to know each other.

But tonight, it's like she's seeing him for the very first time.

♪ Oops, someone's been caught staring.

Maybe she's his quoll-mate.

♪ [Hissing] Or maybe not.

Once the quolls stop hogging all the limelight, we catch a glimpse of one of the rarest mammals on Earth.

This is the first known wild footage of a Kimberley Nabarlek, a tiny rock wallaby that lives amongst the sandstone escarpment.

♪ We don't know much about these gorgeous creatures, but they're thought to be on the brink of extinction.

Feral cats may have almost completely wiped them out on the mainland.

These islands offer a last refuge for many creatures in the region.

Good thing the Dambi Rangers are here, working hard to protect all of the biological treasures on their Country.

[Osprey calling] On the Kimberley coastline, the ocean doesn't just lap the shores, it charges in through the islands.

♪ The tide can rise and fall over 30 feet in a day-- creating violent currents... ♪ and deadly conditions for mariners.

The treacherous ocean has helped to protect the coast from outside influences.

♪ [Bird calling] The tides also breathe life into one of the Dambimangari peoples' most sacred places.

♪ Garaan-ngaddim, the Horizontal Falls, is a deeply spiritual place for Worrorra people.

♪ It's a place they tell us was formed by the "Woongudd," a great creator snake that carved the land and helped to create the laws that people must live by.

♪ [Osprey calling] ♪ The strong currents of this coast mix nutrients from the deep with those that run off the land-- fueling the growth of microscopic plants that form the base of marine food chains.

The minuscule plants are eaten by planktonic animals... which, in turn, feed huge schools of fish.

Millions of seabirds and around 20 species of marine mammal take advantage of this super-productive ocean.

Creatures, like the elusive snubfin dolphin, love it here.

You can tell by the smile.

[Dolphins squeaking] As the season of Barrkana draws to a close, the weather is starting to warm up.

Perfect conditions for one of our most devoted mums.

♪ This little bubba's only 3 weeks old and growing fast!

♪ Mum's providing hundreds of liters of milk a day, and her little one is growing up to a meter each month.

♪ But Mum has to remain on her guard.

There are predators in these waters.

Just outside the calm bay, a pod of false killer whales is on the hunt.

♪ These highly intelligent members of the dolphin family hunt as a pack.

[Whales squeaking] ♪ And they've been known to target vulnerable humpback whale calves.

♪ As the pod moves closer to shore, their calls alert Mum to the approaching danger.

♪ She warns her calf to go quiet and stay close.

♪ The false killers enter the bay and cross paths with an unlucky shark.

♪ It's no match for the 6-meter-long predators.

♪ But just as the falsies hope to consume their catch... ♪ the cavalry arrives.

♪ A group of male humpback whales charge in.

♪ At close to 30 tons, the humpbacks have the upper hand.

♪ In the commotion, the young shark is released and swims over to its saviors.

It's his lucky day.

♪ [Whale calling] [Squeaking] ♪ The male humpbacks chase the pod back out to sea, well away from Mum and bubs.

Humpback whales are social creatures, and they're often observed harassing whale calf predators.

♪ It's nice to be a part of a community that has your back.

The Worrorra people have had a long relationship with these whales.

They're woven into the art and songs of their creation stories.

Kallum: Yeah, before... before Europeans settled here, our people--Worrorra people-- lived on this coastline, just off the land and sea.

They built mangrove rafts, paddled all through this Country.

Narrator: Navigating these pristine waters is nothing new to Kallum's mob.

His ancestors have been seafarers of this saltwater Country since the beginning of time.

During the early days of European invasion, many First Nations people were driven from their homelands.

Those who weren't killed on Country were held in missions where many were forced to work as slave labor.

♪ For Indigenous people, the road back to self-determination has been long and difficult.

But these days, ranger groups across the Kimberley are reclaiming the right to practice their cultural obligations to Country, and in the process, healing both the land and its people.

Kallum: It feels good.

You get a sense of belonging when you are on Country.

Everything comes back and sort of makes sense, in a way.

That we belong to this land and this land belongs to us now.

Narrator: This morning, Ranger Azarnia is heading offshore to check on the coral reefs that flourish in the clear waters.

Azarnia: As an Indigenous woman, like growing up from a small little town, I try to encourage young ones, you know?

The Country needs us.

If I can do it, I'm sure you can do it.

Narrator: The Kimberley coast is lined by thousands of square miles of coral reefs.

♪ This marine wonderland supports a stunning variety of animals.

♪ Especially in the nooks and crannies of the reef.

♪ Like the peacock mantis shrimp.

He may only be the size of your little finger, but he has a superpower.

The most complex and sophisticated eyes in the animal kingdom.

Mantis shrimp eyes are made of thousands of tiny lenses and retinas, and each contains up to 16 different color receptors.

Our eyes only have 3.

♪ They can see ultraviolet light and even polarized light.

They're perfectly adapted to life in the technicolor microworlds of the reef.

♪ Each of his eyes operates independently, giving him a 360-degree view of what's going on.

It's a good thing, too... because there are predators here that love tasty crustaceans.

♪ This octopus is a formidable hunter.

♪ When it decides you're its next meal, it's very hard to escape.

♪ It's never a good idea to rush into dark holes out here.

You never know who might already be in there.

These glowing blue rings spell more trouble for our colorful friend.

They're the calling card of one of the most venomous creatures on the reef.

♪ The small but deadly blue-ringed octopus.

♪ This little wizard is barely the size of a golf ball, but he carries enough venom to kill at least 10 humans.

♪ Our mantis shrimp never stood a chance.

♪ The Kimberley's coral reefs offer a priceless refuge for millions of marine animals.

And it's one of the few places on Earth that hasn't been overfished or polluted by runoff and industry.

Around 250 kilometers by boat from the nearest town lies another of the Dambi people's most sacred places.

And today they tell us something special is going to happen, a phenomenon that few people ever get to see.

♪ For just a few days each month, the full moon draws the ocean away, and something sacred rises from the sea.

♪ This is Yowjab-- Montgomery Reef.

♪ Over 300 square kilometers of living coral.

♪ Azarnia: When I first went there, I couldn't even believe my eyes, you know.

When you're driving and the tide is up, you won't see it.

But then when you sit in the channel and the tide drops, oh, it just open up the Country, you know, it just lights up.

♪ Beautiful, yeah.

♪ I believe that the Country, um, feels us, that we're there, and he knows we're there.

♪ It's very important to bring the rest of the world on that journey-- to look after our Country because we all breathe one air, we share the one ocean, so it'd be good to start looking after it.

♪ Narrator: Just like the tides, the seasons are always shifting.

And now, the cool weather of Barrkana is coming to an end.

Changes on Country are constant, and a deep part of Indigenous culture is understanding how those changes affect the lives of all who call this place home.

♪ We have been studying this place since the beginning of time.

And one of the results of that deep time connection is a profound sense of respect and custodial obligation to the natural world.

This place may look wild and untouched, but it is now and always has been a human landscape.

We don't own Country, we belong to it.

And none of us can survive without it.

♪