Original subtitles

(dramatic music)

- [Woman] In the ancient rainforest of northeast Australia,

a living dinosaur is making a last stand.

This magnificently weird creature is known

as the world's most dangerous bird,

the mysterious cassowary.

Meet Bertha, she is massive and powerful.

But she's up against tough odds.

Everywhere in the forest rivals and predators

threaten her eggs and young.

For her species to survive, she must run a constant race

to keep breeding.

This is the story of Bertha,

a prehistoric and endangered dino bird.

Australia is a land of deserts.

But the far north reaches up into the wet tropics

and this region is home to a mature stand

of ancient rainforest,

almost unchanged for millions of years.

(birds chirping)

In this patch of rainforest,

Bertha is the mistress of all she surveys.

She looks like a cross between an ostrich

and a velociraptor.

(dramatic music)

A great grandmother of the forest,

she is now more than 40 years old.

A flightless giant, she stands nearly 180 centimeters tall

and weighs 70 kilograms.

(water splashing)

No bird in the world is quite like the cassowary

and no single cassowary is quite like Bertha.

The large boney cask crowning her head

attests to her great age.

Perhaps the larger the cask, the more dominant the bird.

And Bertha's cask is one of the largest.

It slants slightly to the right,

making her easy to recognize.

In the world of cassowary, females rule.

(dramatic music)

Bertha's territory is one of the best.

Three kilometers squared of ancient rainforest.

(dramatic music)

Towering peaks feed the creeks that course through

her territory.

(water babbling)

With such a lush forest in her possession,

(birds chirping)

she has command over the best males.

So it's no surprise that Bertha is pregnant.

Now her massive body needs even more fuel than usual.

For the cassowary, this means fruit and lots of it.

(insects chirping)

(plucky orchestral music)

Hunger drives her to visit an abandoned orchard

in the center of her territory.

A reliable source of fruit when it's scarce in the forest.

While some morsels can be had with a simple pluck,

(plucky orchestral music)

others require more effort.

She has only vestigial wings,

so her legs have become her way to fly.

They can launch her 1.5 meters in the air.

It's the start of the dry season

and Bertha's territory still gets occasional downpours.

This is when Bertha prefers to lay her eggs.

But it appears that she is being watched.

It's a male name Crinkle Cut,

the father of her developing eggs.

Crinkle Cut keeps a respectful distance

from his formidable mistress.

Crinkle Cut is Bertha's favorite partner

and every breeding season for the last five years,

she has mated with him first.

While it's not a close relationship,

Crinkle Cut has the qualities Bertha desires.

He is a great dad.

In cassowary, it's the males that raise the young.

Extremely rare in nature, male only parenting occurs

in just 1% of all bird species.

(dark instrumental music)

Bertha lays each of her 600 gram eggs directly

on to the forest floor.

This is the moment that Crinkle Cut has been waiting for.

From the moment her eggs are laid,

Bertha's parental duties are done and she melts

into the forest without a backward glance.

(bird grunting)

Crinkle Cut's parental instincts take over.

He shades and guards the eggs, turning them regularly

to ensure they develop evenly.

Crinkle Cut is an experienced father

and Bertha has chosen a nest site

in the heart of her territory.

Crinkle Cut will brood Bertha's eggs for the next 52 days.

It will be a long and lonely vigil.

Despite the dedication of the males,

many chicks won't survive.

So Bertha can't afford to breed just once a year.

(sweeping instrumental music)

Shortly after laying a clutch of eggs,

she's ready to mate again and off in search

of other devoted dads.

The destruction of tropical forests has meant that

not all cassowaries have the luxury of living

in the pristine part of the forest.

Some are forced to become fringe dwellers.

This male lives on the edge of Bertha's territory.

His name is Buster.

He has learnt to survive in this disturbed part

of the forest

and he is advertising his availability.

Using specialized long distance calls,

the low frequency travels further,

rumbling along the forest floor

and through the vegetation.

(bird call rumbling)

It's an effective way to be heard in such a dense forest.

(bird call rumbling)

And Bertha is highly tuned to the lure of this love song.

(insects and animal chattering)

(bird call rumbling)

Her cask may be an ancient receiver of sorts.

Inside, it has a honeycomb-like structure

and an extensive vascular network

thought to enhance the cassowary's sensitivity

to these low frequency sounds.

(bird call rumbling)

This method of communication is believe to have first

occurred in dinosaurs.

Bertha picks her way through the primeval rainforest

to the very fringe of her territory.

A mile from where Crinkle Cut is now sitting on her eggs.

It's a blind date but she has another chance to reproduce.

(dramatic music)

She emerges from her emerald green forest

(water splashing)

and there's the object of her present desire.

It's Buster.

Female cassowaries are usually 25% larger than males.

And Bertha is among is among the biggest and bossiest.

Their approach is tentative.

Her regal presence is intimidating the young Casanova.

Buster is only 13 years old.

(dramatic music)

One wrong move and he can ruin the courting

and possibly be punished for it.

He sticks close to her but not too close.

And begins his courting display.

(dramatic music)

He displays his bright colors and preens his feathers.

It seems her majesty is not displeased.

Giving up the single life for the next few weeks,

they'll form an uneasy partnership.

This will be one of several matins over the coming weeks.

It's one of the few times that Bertha appears

to be submissive.

Within a few weeks our matriarch has seduced two

dedicated dads into protecting her progeny

on two different nests.

(dramatic music) (birds calling)

While Bertha has been off chasing younger men,

dutiful Crinkle Cut has remained on the nest,

enduring the worst of the dry season.

(insects chirping)

He's doing his best to shade the precious eggs.

But he still has two more weeks before they'll hatch.

The dry season shows on sign of abating.

Eels must cross dry land in search of the last

remaining water holes.

Trees shed their leaves in an attempt to prevent water loss.

A thick layer of leaf litter builds on the forest floor,

perfect conditions for a leaf litter specialist.

The orange footed scrub fowl rake through the leaf litter

in search of moisture laden worms and insects.

(dramatic music)

The pair have to visit the creek daily

and this water hole is the last one left.

Bertha is a regular here.

With no sweat glands and covered in black hair-like feathers

Bertha has to avoid the sun, where she can quickly overheat.

In this weather, she prefers to stay hidden

in the darkest parts of the forest.

Buster, who is currently minding Bertha's second batch

of eggs, is in a bind.

Here at the thin edge of the forest near the beach,

his home is more exposed to the relentless sun.

Overheating and panting to try to cool down,

he's gone in search of water.

Left in the open and with their minder no where in sight,

the four eggs quickly attract attention.

(ominous instrumental music)

But while young Buster is still at the creek,

a more serious threat appears and approaches the nest.

It's a female but it's not Bertha.

In this forest, competition between females is intense.

Buster returns but it's too late.

He doesn't interfere.

Female cassowaries rule the roost,

even if they're destroying it.

And she could inflict a serious injury

with her spiked claws.

He can only cower and watch

the complete devastation of his family.

(soft somber instrumental music)

Buster surveys the damage.

All that hard work now wasted.

He abandons what's left of the nest,

knowing he cannot stop the intruding female.

As dusk falls, a feral pig arrives on

the scene of the crime.

These aggressive omnivores usually pose an even greater

threat to cassowary nests than rival females.

But this pig finds the hard work

has already been done for him.

A whole brood, destroyed.

Bertha's laid eight eggs and now only four remain.

As night falls and the cassowaries sleep,

a strange cast takes the stage.

(dark instrumental music)

Bioluminescent fungi provide the lighting.

Mammals appear, hungry from a long day in hiding

and with them villains.

This is the amethystine python.

Heat sensing pits in his lower jaw allow him to see

his mammalian prey in the dark.

Being cold blooded, this white lipped green tree frog

should be safe.

Crinkle Cut is in the last week of guarding his eggs.

Defending your nest in the rainforest is one of the most

important things a bird can do.

Especially with lace monitors on the prowl.

These monitors are nest raiders.

Crinkle Cut is on guard so the monitor has his work cut out.

Perhaps an easier meal is on offer.

Nearby bird calls have caught the attention

of the lace monitor.

These white streamers belong to one of the rainforest's

more colorful visitors.

The buff breasted paradise king fisher has made

its annual migration here from New Guinea to breed.

Good news for the hungry lace monitor.

This king fisher pair has commandeered a termite mound

for its nest.

Having laid their eggs in the center of the mound,

they are now caring for three young chicks,

the source of all the noise.

The parents collect insects all day long.

(baby birds chirping)

But the shrill demands from within the mound

never stop begging for more.

With the parents busy, the lace monitor makes his move.

(dramatic music)

(baby birds chirping)

It would seem that the chicks are doomed

but the pair return to defend their territory and the nest.

(ominous music)

(baby birds chirping)

The lace monitor decides to head off in search of food

that won't fight back

and the parents can relax.

But only for a moment.

(thunder rumbling) (whimsical orchestral music)

The oppressive dry season finally relents.

The start of the wet season brings with it a new menu

of rainforest fruit and just in time for Crinkle Cut.

His patience has finally paid off.

He's now a proud father.

Three of Bertha's four eggs have hatched successfully.

Bertha may not be the most faithful partner,

so there's no guarantee that all three chicks are his.

(plucky instrumental music)

But he cares for them all equally.

The chicks are striped for camouflage in the leaf litter.

They won't get their elaborate adult colors

until four years of age.

The little ones mimic his every move.

He breaks the fruit apart for the chicks.

They're capable of swallowing some fruit whole.

Occasionally they get a little too ambitious.

Crinkle Cut's chicks are only three weeks old

and dad keeps them close.

(thunder rumbles)

Finally, the wet season has begun.

It's a welcome relief for Bertha.

In search of the new season's figs,

she's moved down to the swollen creek.

The water is now deep.

And hides the infamous salt water crocodile,

the largest predator in Australia.

(ominous music)

It's an ambush predator and will silently

and patiently stalk its prey.

He needs Bertha to venture into deeper water

where he lies waiting.

Not the wisest place to stop.

(dramatic music)

Perhaps an easier meal is on offer. (pig snorts)

A feral pig forages the river bank.

It hasn't seen the crock. (dramatic music)

(water splashing)

Thankfully for Bertha and the forest,

this crock has a taste for pork.

With an estimated 60,000 feral pigs infested

into the remaining cassowary habitat,

they are a serious threat to Bertha's chicks.

Now that Crinkle Cut's chicks are older,

their ranging further afield in search of food.

(dark instrumental music)

The leaf litter harbors much more than fruits and berries.

The amethystine python rarely hunts during the day

but is attracted by the sounds

of our cassowary family foraging.

(ominous instrumental music)

A cassowary chick would be a significant meal.

Crinkle Cut spots the snake.

(cassowary rumbling)

He stands tall and clucks aggressively.

His feet speak to his dinosaur ancestry

with three massive toes.

The inner one, a deadly spike.

The cassowary is one of only two birds

to have every killed a human.

The python will lie in wait, camouflaged in the leaf litter.

But with Crinkle Cut on guard,

the python retreats to the canopy.

(dramatic music)

Crinkle Cut defended his brood from the snake,

but in the confusion, two of the chicks have wandered off.

(slow instrumental music)

If the missing chicks are left alone for too long

they'll begin to attract unwanted attention.

The remaining chick, Wondu, is the smallest

and least confident.

Crinkle Cut's search brings him to the creek,

which is now flowing strongly.

Crinkle Cut's missing chicks could be on the other side.

But in crossing, Wondu could be swept away.

Sure at first, Wondu quickly thinks better of it.

Crinkle will have to search for another place to cross.

(ominous music)

This looks better

and there is a surprise waiting for Crinkle Cut

on the other side.

(plucky instrumental music)

The family has been reunited.

(sweet instrumental music)

Wondu and his siblings still have a lot to learn.

Usually cassowary chicks aren't ready to strike out

on their own until they're nine months old.

If they make it that far.

Bertha's territory is home to a wide spectrum

of colorful critters.

Some need to stand out from the crowd

but others prefer camouflage.

If the disguise isn't perfect,

there's many hungry mandibles waiting.

(dramatic music)

Cassowary choose to be seen.

They have bright red waddles on their neck

and the ability to see ultra violet light,

making these colors especially the blue,

even brighter to their eyes.

(thunder cracks)

The wet season is now at its most intense.

20 centimeters of rain fall in a single 24 hour period.

During these massive storms, Bertha hunkers down

to wait out the worst.

(water crashing) (dramatic music)

This heavy wet season rain has loosened the soil

and brought down an old rotten tree.

Here, where sunlight now floods the forest floor,

cassowary and plant forge a fascinating relationship.

A viscously self-protective plant takes root

in the newly disturbed soil.

Fast growing and a pioneer in the disturbed landscape,

the stinging tree is armed with silicon shards,

like powdered glass.

Most animals that touch them are in for a world of pain.

Browsers would be wise to give them a wide berth.

The storm has brought a new bounty of fruit for Bertha.

The hundreds of fruits she eats a day

take a rapid, but gentle trip through her gut,

which strips away only the flesh.

Soon, Bertha makes her way

to this sunny patch in the forest.

In passing, she leaves her seed-rich droppings

in this new forest opening.

Complete with her own compost.

The perfectly cleaned seeds, primed by her unique

digestive juices, are now under the protection

of the pain inducting plant.

The seeds, which may have come from a tree more than

a mile away can germinate and grow unmolested by herbivores.

This tree, the ripa rosa, was certainly planted this way.

It needs the cassowary for survival.

This endangered ripa rosa tree will germinate

92% of the time after the seed

is passed through a cassowary.

The seeds that don't make this journey germinate

only 4% of the time.

Eventually, the trees will reach the canopy and block

the sun once again,

providing habitat for all other forest dwellers.

(sweeping instrumental music)

Over thousands of generations, cassowary like Bertha

have shaped their territory.

The forest is now world heritage listed.

But it can never be totally safe,

for dangerous and destructive invaders abound.

Feral pigs, they're ravenous fruit eaters too.

Robbing Bertha and her offspring of much needed sustenance.

They destroy potential cassowary habitat,

threatening the survival of the species.

And the pigs also bring another terrible threat

to the cassowary,

pig hunting dogs,

bred to track and chase down feral pigs

until their owners can kill them.

(dramatic music)

They wear protective gear around their necks and chest

to ward off the pig's sharp tusks.

A cornered pig is a very dangerous one.

(dramatic music) (dogs barking)

The dogs are swift but Crinkle Cut's alert.

He is capable of killing dogs

but he can't protect his vulnerable chicks at the same time.

His family stands little chance against this marauding mob.

The day after the pig hunt

two of Crinkle Cut's chicks are gone.

It's a devastating blow.

Bertha and Crinkle Cut now have only one chick left, Wondu.

All Crinkle Cut's effort's now focused on Wondu's survival.

The promise within Bertha's eight eggs has been reduced

to one surviving chick.

(whimsical instrumental music)

Deep in the darkest part of the forest,

a lovely, if strange bit of architecture is taking shape.

Rising between two saplings is a delicately decorated bower.

It's not a nest.

This maypole of sticks is a form of seduction

and this is the architect, a male golden bow bird.

He has been spending weeks on his masterpiece,

ornamenting it with lichen and flowers.

He selects and places each decorative touch with care.

His mating success depends upon it.

If the bower is impressive enough,

a female may consent to mate with him.

The bower is purely for show.

The female will build a separate nest elsewhere.

(sweet instrumental music)

There is now only one surviving chick from the year's brood.

With all the devotion and protection afforded an only child,

Wondu has made it to seven months old.

Living on Bertha's territory has ensured

he's always been well fed.

He has lost his boyhood stripes in favor of teenage

muted brown feathers.

He's more and more independent, venturing further from

Crinkle Cut as he searches for fallen figs.

Unknown to him, he's going to need this self reliance

sooner than most chicks.

He's about to be driven fro his rainforest home.

Crinkle Cut and Wondu forage near the edge of their range.

An extremely dangerous edge.

Several cassowary are killed on roads every year.

But today the threat is not traffic,

it's Bertha.

Bertha has the desire to mate again.

Cassowaries usually mate in the dry season,

but the sudden glut of wet season fruit may have fired up

Bertha's reproductive urges.

This is desperately bad news for Wondu.

To mate with Crinkle Cut,

she'll need Wondu out of the picture.

While it seems brutal,

there's cold evolutionary logic behind it.

(bird call rumbling)

If she mates now, she could have a successful clutch

while the forest is still wet and full of fruit.

With Buster's clutch destroyed and two chicks

killed by dogs, she has to try and keep breeding.

(dramatic music)

She can never rest.

(bird call rumbling)

Crinkle Cut hasn't raised Wondu

for the full nine months yet.

And he isn't ready to relinquish him,

so he lets Bertha know his disapproval.

(slow instrumental music)

But as usual, Bertha prevails.

If Wondu is going to survive,

he'll need to find a territory of his own.

He won't be tolerated in Bertha's patch of forest for long.

As he begins his journey,

he passes through Bertha's orchard.

It's no longer the safe haven for him it once was.

It may be several years before he finds a good

rainforest territory of his own.

With Wondu gone, Bertha and Crinkle Cut were able

to breed successfully again.

Crinkle is now sitting on Bertha's next clutch.

Since she began breeding over 35 years ago,

Bertha has laid countless eggs, giving rise to dozens

of cassowaries, who have survived to adulthood.

She has forged a dynasty.

Her offspring, just like Wondu, now garden and protect

their own parts of the rainforest

and engage in the endless quest to breed.

(sweeping instrumental music)

But for now, Bertha is still strong

and the queen of her forest and she's searching once again

for her next mate.

(bird call rumbling) (dramatic music)