Narrator: OUTBACK AUSTRALIA.

IT'S KNOWN AS "THE LAND OF OZ."

ACROSS ITS EVERY EXTREME, THERE ARE BIRDS OF A DIFFERENT COLOR.

[ CALLING ] THEY'RE THE BRIGHTEST CAST OF CHARACTERS IN THE AUSTRALIAN STORY.

THEY ROUTINELY GET THE BEST OF FARMERS.

THEY TRY TO OUTWIT EACH OTHER.

Man: WE ACTUALLY CAUGHT THEM OUT, PLAYING A LITTLE MATING GAME OF THEIR OWN.

[ IMITATES BIRD CALL ] [ CALLING ] THERE IS COMPLICATED THOUGHT GOING IN THAT BIG HEAD OF THEIRS.

Abraham: ROWDY AND RESOURCEFUL, THEY'RE AUSTRALIAN ORIGINALS.

THEY'RE PARROTS IN THE LAND OF OZ.

Narrator: BEFORE AUSTRALIA HAD DESERTS, RAIN FORESTS COVERED THE CONTINENT.

TODAY, JUST A FEW ISOLATED PATCHES REMAIN.

THESE LUSH POCKETS SURVIVE, THANKS TO THE TROPICAL MONSOONS THAT SWEEP ALONG THE FAR NORTH COAST, BRINGING TORRENTIAL RAIN.

IN THESE FORESTS, A BRILLIANT ARRAY OF PARROTS ADAPTED CRAFTY BEAKS AND DEXTEROUS TOES TO CRACK THE RICH BOUNTY OF SEEDS AND FRUIT.

[ BIRD CALLING ] THE TINIEST OF ALL, THE FIG PARROT, GORGES ON FRUIT BIGGER THAN ITS HEAD.

[ BIRDS CALLING ] THE GENERAL RULE FOR THE MALES HERE IS TO BE AS COLORFUL AS NEEDS BE TO ATTRACT A MATE WITHOUT BECOMING A NEON LURE TO PREDATORS.

THE KING PARROT IS BRASH, [ CALLING ] WHILE THE GREEN FEATHERS OF THE RED-CHEEKED PARROT BLEND INTO THE FOLIAGE.

HE RELIES ON HIS SEXY RED HEAD AND BRIGHT, BEADY EYES TO GET THE FEMALES.

[ BIRDS CALLING ] BUT ONE OF THE MOST AMAZING BIRDS IN THE WORLD IS THE ECLECTUS PARROT, BECAUSE IT BREAKS VIRTUALLY EVERY RULE IN THE EVOLUTIONARY RULE BOOK.

THE MALE IS GREEN AND THE FEMALE, RED.

SO STRIKINGLY DIFFERENT ARE THEY THAT FOR A LONG TIME PEOPLE THOUGHT THAT THE TWO MUST BE SEPARATE SPECIES.

[ CALLING ] SCIENTIST ROB HEINSOHN SET OUT TO DISCOVER THE SECRETS OF THIS RARE CREATURE.

Man: ECLECTUS PARROTS ARE THE PINNACLE OF PARROT EVOLUTION.

THEIR COLORATION HAS GONE INTO UNCHARTED WATERS.

THEY ARE SO DIFFERENT, AND I JUST NEEDED TO KNOW WHY.

[ CALLING ] OKAY... WELL, I'VE DISTURBED THEM NOW, BUT I HAD TO DO THAT JUST TO SEE IF THEY WERE OCCUPYING THE HOLLOWS.

AND ONE DID, INDEED, COME OUT OF ONE OF THE HOLLOWS, SO IT'S A VERY GOOD SIGN AT THIS STAGE.

AND IT DOES MEAN THAT IT'S WORTH PUTTING A LINE UP AND CLIMBING THE TREE AND HAVING A CLOSER LOOK.

Abraham: BUT THERE WAS JUST ONE PROBLEM.

Heinsohn: I HAVE A TERRIBLE, TERRIBLE FEAR OF HEIGHTS.

I WAS GETTING DIZZIER BY THE MOMENT, BUT I WAS ALSO DRIVEN BY AN INCREDIBLE DESIRE TO SEE WHAT WAS INSIDE THOSE HOLLOWS.

SO I OVERCAME THAT FEAR, I FORCED MYSELF TO STAY STEADY ON THE ROPE AND TO KEEP CLIMBING.

HEY, LINDSAY.

GOT EGGS.

THAT'S ABSOLUTELY FANTASTIC.

IT MEANS THEY'RE BREEDING AGAIN.

I'LL JUST GO UP TO THE OTHER HOLE AND SEE HOW THEY'RE DOING.

Heinsohn: AND I WENT UP 15 METERS, 20 METERS, 25 METERS.

AND FINALLY I REACHED THE NEST HOLE I WAS LOOKING FOR.

I REACHED INSIDE, HAD A LOOK INSIDE, AND THERE WERE TWO BEAUTIFUL LITTLE CHICKS.

[ BIRD CALLING ] YEAH, WE'VE GOT CHICKS IN HERE.

THEY'RE BEAUTIFUL, TOO.

Abraham: FOR THE LAST EIGHT YEARS, ROB HAS STUDIED THE FEMALE AND ALL HER CHICKS THAT LIVE IN THIS HOLLOW.

HE MEASURES AND MARKS EACH ONE AND MONITORS THEIR GROWTH.

THIS DOESN'T SEEM TO UPSET THE CHICKS OR STOP THEIR MOTHER FROM NURTURING THEM.

Heinsohn: OUR NUMBER-ONE FEMALE, A STAR PERFORMER, SHE'S JUST DONE WHAT SHE TYPICALLY DOES -- PRODUCES HEALTHY LITTLE GUYS LIKE THIS, AND THEY GET A VERY GOOD START FOR THEIR LONG LIFE IN THE RAIN FOREST.

Abraham: A GOOD HOLLOW IS HARD TO FIND.

AND THE FEMALE GUARDS HERS FIERCELY.

Heinsohn: WE'VE SPENT A LOT OF TIME JUST WATCHING HER AT THE NEST HOLLOW.

WE BUILD HIDES IN NEIGHBORING TREES, AND WE SPENT A LOT OF TIME IN THE TREETOPS.

AND WE JUST WATCHED THE FEMALE'S BEHAVIOR.

Abraham: ROB'S FAVORITE FEMALE IS NOT TAKING ANY CHANCES WITH HER HOLLOW AND DOESN'T BUDGE FOR THE ENTIRE NINE-MONTH BREEDING SEASON.

SHE IS TOTALLY RELIANT ON THE MALE TO BRING HER FOOD.

Heinsohn: A BIT LIKE MEALS ON WHEELS.

SHE'S ACTING LIKE AN INVALID, STAYING AT HOME, AND THE MALES ARE OUT THERE, DOING ALL OF THE WORK, COMING AND GOING ALL DAY LONG, PURELY FOR THE RIGHT TO REGURGITATE SOME FOOD TO HER.

AND OF COURSE THEY'RE HOPING TO GET SEX IN RETURN.

[ CALLING ] Abraham: BUT THIS FEMALE WASN'T JUST BEING ATTENDED BY ONE MALE.

SHE WAS GETTING LOTS OF ATTENTION.

IN FACT, SEVEN MALES WERE LINING UP TO FEED HER.

[ BIRD CALLING ] AND SHE WAS MATING WITH ALL OF THEM.

Heinsohn: AND WE WORKED OUT THAT THIS WAS, IN A WAY, A FORM OF TRICKERY.

SHE WAS TRYING TO GIVE THEM THE IDEA THAT THEY ALL HAD A CHANCE OF BEING THE DADS.

AND THAT WOULD GIVE THEM EXTRA INCENTIVE TO GO OFF AND FIND THE FOOD.

Abraham: BUT DNA TESTS ON THE CHICKS' FEATHERS REVEALED SOMETHING ASTONISHING.

OF THE 24 YOUNG SHE'S PRODUCED IN THE LAST EIGHT YEARS, 19 ARE FROM THE SAME SUPER-STUD MALE.

TO COMPLETE THE PICTURE, ROB WANTED TO KNOW HOW FAR THE MALES WERE GOING ON THEIR FEEDING TRIPS.

Heinsohn: WE CAPTURED A WHOLE LOT OF MALES, AND WE PUT TRANSMITTERS ON THEIR TAILS.

WE MOUNTED AERIALS ON THE WINGS OF THE PLANE.

AND WE SET OUT AND FOLLOWED THEM ACROSS COUNTRY FROM THE SKY.

Abraham: INCREDIBLY, THE LOVESICK MALE GATHERED FOOD FROM A HOME RANGE OF ABOUT 40 SQUARE MILES.

Heinsohn: IT ALSO TURNED OUT THAT HE WAS ATTENDING MORE THAN ONE FEMALE.

AND SOME OF THEM HAD THREE OR FOUR DIFFERENT FEMALES THAT THEY WERE VISITING AND FEEDING AND, INDEED, MATING WITH.

SO, BY FOLLOWING THEM AROUND THE LANDSCAPE, WE ACTUALLY CAUGHT THEM OUT PLAYING A LITTLE MATING GAME OF THEIR OWN.

Abraham: AFTER VISITING THEIR GIRLFRIENDS, THE MALES FLY BACK TO ROB'S FAVORITE FEMALE.

Heinsohn: THE MALES OFTEN COME BACK TO THE NEST TREE AT THE SAME TIME.

AND WHEN THAT HAPPENS, THERE'S A LOT OF ARGY-BARGY.

[ SQUAWKING ] [ SQUAWKING CONTINUES ] Abraham: WITH SUCH DIFFERENT LIFESTYLES, THE HUGE COLOR DIFFERENCE BETWEEN THE SEXES MAKES A LOT OF SENSE.

[ SQUAWKING ] Heinsohn: THE MALE IS GREEN.

VERY IMPORTANT FOR THEM TO REALLY CAMOUFLAGE WHEN THEY GO ACROSS COUNTRY GETTING FOOD FROM THE FRUITING TREES.

MALES SEEM TO USE THE BIT UNDER THEIR WINGS VERY JUDICIOUSLY TO GET THE FEMALES' ATTENTION.

IN CONTRAST, THE FEMALE'S RED IS A VERY CONSPICUOUS LONG-DISTANCE SIGNAL.

SHE SHINES LIKE A BEACON THAT SCREAMS AT OTHER BIRDS, ESPECIALLY FEMALES, "KEEP AWAY, THIS HOLLOW "IS OCCUPIED, DON'T BOTHER COMING NEAR, BECAUSE I WILL BEAT YOU UP."

Abraham: NO OTHER BIRD IN THE WORLD MATES LIKE THIS.

[ CALLING ] IT'S A SEX STRATEGY THAT'S BEEN PERFECTED OVER AN INCREDIBLY LONG TIME IN THESE ANCIENT FORESTS.

WHILE THE ECLECTUS WERE DOING THEIR THING, ELSEWHERE ON THE CONTINENT, DRAMATIC CHANGES GAVE RISE TO A WHOLE NEW RANGE OF PARROTS.

MILLIONS OF YEARS AGO, MOST OF AUSTRALIA'S RAIN FORESTS GRADUALLY DRIED AND BECAME OPEN WOODLANDS.

MANY PARROTS WERE ABLE TO ADAPT TO THE NEW AND TOUGHER CONDITIONS.

[ CALLING ] TO SURVIVE ON THE DESERT EDGE, RED-TAILED BLACK COCKATOOS STICK TO THE FEW TREE-LINED WATER COURSES.

[ SQUAWKING ] AS THE SUN DROPS, THE BIRDS ARRIVE FROM ALL DIRECTIONS.

WITH BREEDING HOLLOWS SCARCE, MOST OF THESE COCKIES ARE SINGLE.

THE LOCAL WATERING HOLE IS THEIR PICK-UP JOINT.

AND THE EVENING QUICKLY TURNS INTO A BOISTEROUS PARTY.

[ SQUAWKING ] YOUNGER BIRDS FLIRT BY DISPLAYING THE COLOR BANDING ON THEIR TAILS AND RAISING THEIR CRESTS.

THESE FANCY POP-UP CRESTS ARE WHAT DISTINGUISH COCKATOOS FROM THE OTHER PARROTS.

[ CALLING ] [ ALL CALLING ] THESE OPPORTUNISTIC COCKIES THRIVED AND SPREAD OUT AS THE CONTINENT DRIED.

DURING THE LAST ICE AGE, WINDS LASHED THE LAND AND HEAPED SAND INTO VAST DUNES.

GRASSES AND SHRUBS SPREAD ACROSS THE DESERT, PRODUCING AN ABUNDANCE OF SEEDS.

[ CHIRPING ] THE GALAHS WERE QUICK TO TAKE ADVANTAGE OF THE NEW FOODS.

THEY WENT JUST ABOUT EVERYWHERE, EATING ALMOST ANYTHING.

[ CHIRPING ] TODAY, THERE'S BARELY A PATCH OF AUSTRALIA WITHOUT THESE EXTROVERTED COCKIES.

BUT THE OPPORTUNISTIC GALAHS WERE NOT THE ONLY ONES TO TRY NEW FOODS.

THE LESS COMMON MAJOR MITCHELL COCKATOOS HAVE RECENTLY ACQUIRED A TASTE FOR PADDYMELONS.

[ SQUAWKING ] THESE INQUISITIVE BIRDS HAVE LITTLE TROUBLE WORKING OUT SOME FANCY FOOTWORK TO BREAK INTO THE FRUIT.

THEIR NEW CUISINE ARRIVED AS PART OF AN EXOTIC SMORGASBORD.

150 YEARS AGO, CATTLEMEN PUSHED THEIR WAY TO THE DESERT CENTER.

AND WHEREVER THEY WENT, THEY BROUGHT A WHOLE RANGE OF NEW OPPORTUNITIES FOR PARROTS TO EXPLOIT.

[ CALLING ] PADDYMELONS WERE INTRODUCED TO FEED THE CAMELS OF THE AFGHAN TRADERS AS THEY TRAVELED THE OUTBACK SUPPLYING THE ISOLATED PROPERTIES.

IT WAS A TOUGH LIFE FOR THE EARLY PIONEERS.

AND FREQUENT DROUGHTS MADE IT HARD TO MAKE A LIVING.

ADDING TO THE FARMERS' WOES, THE COCKATOOS SOON WORKED OUT THAT WHERE THERE WAS STOCK...

THERE WAS STOCK FEED.

ALL THIS FREE FAST FOOD MADE LIFE PRETTY CUSHY FOR GENERATIONS OF COCKATOOS, AND THEIR NUMBERS BOOMED.

[ CALLING ] AND THE GOOD TIMES KEPT ON ROLLING FOR THE COCKATOOS AND PARROTS...

WHEN THE SETTLERS FOUND UNDERGROUND WATER AND PUMPED IT TO THE SURFACE.

MAN-MADE WATER HOLES HELPED PARROTS SPREAD AND SURVIVE WHERE THEY COULDN'T HAVE DONE BEFORE.

RINGNECK PARROTS... BUDGERIGARS... PALE-HEADED ROSELLAS, ALL COME IN TO DRINK IN FAMILY GROUPS.

MULGA PARROTS CAN LIVE IN WATERLESS AREAS, BUT NO ONE IN THE OUTBACK TURNS DOWN A FREE DRINK.

RAIN RARELY FALLS IN THE AUSTRALIAN DESERTS -- DROUGHTS CAN LAST FOR OVER A DECADE.

WATER HOLES TURN TO MUD... LEAVING A FRESHWATER CRAYFISH EXPOSED... AND AN EASY TARGET.

THE WILDLIFE HAS ADAPTED TO SURVIVE THE TIMES WHEN THE RIVERS VANISH INTO PUDDLES... AND THE DAMS ARE TURNED TO CRACKED AND USELESS CRUSTS.

THE AIR CRACKLES IN THE HEAT.

CROPS ARE WIPED FROM THE EARTH.

AND THE PARCHED INTERIOR WAITS FOR RAINS THAT NEVER SEEM TO COME.

THE FIRST SIGN THAT THE DROUGHT MIGHT BREAK CAN BE A WARMING OF THE WESTERN PACIFIC OCEAN.

CYCLONES FORM BY SUCKING UP HEAT AND MOISTURE FROM THE SEA AS THEY POWER IN TOWARDS THE COAST.

WINDS OF UP TO 150 MILES AN HOUR SHRED THE SHORELINE.

AS THE CYCLONE HEADS INLAND IT WEAKENS AND TURNS INTO A HUGE RAIN DEPRESSION.

THE DELUGE SWEEPS NEARLY 2,000 MILES ACROSS THE CENTER OF THE CONTINENT.

AND COCKATIELS CELEBRATE WITH A RAIN DANCE.

WITHIN HOURS, EVERY RIVERBED FILLS WITH LIFE-GIVING WATER.

THE TORRENT CHARGES THROUGH THE NARROW GORGES OF THE RANGES, ERODING THE LAND.

RIBBONS OF NOURISHMENT SNAKE ACROSS THE CONTINENT, TOWARDS THE PARCHED CENTER.

IN THE CHANNEL COUNTRY, THE CREEKS FAN OUT ACROSS PREVIOUSLY BARREN FLOOD PLAINS.

AND FOR A BRIEF TIME THE DESERT IS GIVEN THE KISS OF LIFE.

IN A FLASH, DESERT PLANTS PRODUCE VAST QUANTITIES OF SEED.

SOMEHOW, WATER BIRDS SENSE THE TRANSFORMATION AND TRAVEL GREAT DISTANCES.

FISH BREED AND MULTIPLY IN THE NEWLY FORMED LAKES, PROVIDING A FEAST FOR GROWING CORMORANTS.

AUSTRALIAN CRANES ARRIVE IN SEARCH OF THE ROOTS OF SEDGES.

AND WHEN NATIVE GRASSES START TO SEED, THE SCENE IS SET FOR THE ARRIVAL OF THE STARS OF THE AUSTRALIAN DESERT... BUDGERIGARS.

WE KEEP THEM IN CAGES.

BUT IN THE WILD, BUDGIES ROAM THE VAST OUTBACK.

WHEN IT RAINS, FLOCKS SWOOP IN FROM EVERYWHERE.

NO ONE KNOWS HOW THEY NAVIGATE.

PERHAPS THEY HOME IN ON THE LOW-FREQUENCY SOUNDS OF THUNDERSTORMS THOUSANDS OF MILES AWAY.

THEIR AIM IS TO BREED FURIOUSLY WHILE THE CONDITIONS ARE RIGHT.

ALONG THE GORGES OF THE CENTRAL RANGES, EVERY TREE HOLLOW IS ALIVE WITH THE FLUTTERINGS OF COURTSHIP.

THE RIVERBANK IS PERFECT FOR A DINNER DATE.

IN THE BUDGIE MATING GAME, YOU NEED TO BE CAMOUFLAGED WHILE FEEDING ON THE GROUND, BUT STILL FLASHY ENOUGH TO IMPRESS A POTENTIAL MATE.

AND THE WAY BUDGIES SEE EACH OTHER'S FEATHERS IS DIFFERENT THAN THE WAY WE SEE THEM.

WE SEE IN RED, GREEN, AND BLUE.

BUT BUDGIES HAVE A FOURTH CELL IN THEIR EYE THAT ENABLES THEM TO SEE ULTRAVIOLET.

WHEN UV RAYS HIT SOME PARTS OF THE BUDGIE'S PLUMAGE, THEY GIVE OFF A REFLECTIVE GLOW.

IT'S A FAIR BET THE FEMALE WILL CHOOSE THE BRIGHTEST, SEXIEST MALE...

ESPECIALLY IF HE CAN FIGHT, TOO.

WITH HIS RIVAL DISPATCHED, THE MALE CAN NOW GET DOWN TO THE SERIOUS BUSINESS OF WOOING THE FEMALE.

NOT ONLY DO BUDGIES HAVE HIGHLY REFLECTIVE UV MARKINGS, SOME PARTS OF THEIR PLUMAGE ACTUALLY BECOME FLUORESCENT... THEIR NECKS AND HEADS, IN PARTICULAR.

THE FEATHERS DON'T LIE.

TO MAKE SEXY FEATHERS, THE MALE MUST BE HEALTHY AND PARASITE FREE.

THESE MARKINGS ANNOUNCE, "MY GENES ARE GREAT.

CHOOSE ME."

AND IF SHE DOES, HE TREATS HER TO DINNER BY REGURGITATING FOOD INTO HER MOUTH.

OVER A FEW DAYS, SHE'LL LAY ABOUT SIX EGGS THAT WILL HATCH IN JUST A COUPLE OF WEEKS.

[ CHIRPING ] SHE FEEDS HER BLIND, NAKED CHICKS A RICH, MILK-LIKE LIQUID.

THEY GROW RAPIDLY.

WITHIN 12 DAYS, THEIR WING FEATHERS COME THROUGH.

AND AFTER ONLY FOUR WEEKS, THEY'RE ALMOST READY TO LEAVE THE NEST.

INCREDIBLY, THESE CHICKS WILL BE READY TO BREED IN JUST 60 DAYS AFTER HATCHING.

IT'S A SUPER-QUICK TURNAROUND TO GET THE YOUNG OUT OF THE NEST WHILE THE GOING IS GOOD.

BUT IT COULD BE ALL OVER IN AN INSTANT.

AT SIX FEET, THE PERENTIE IS AUSTRALIA'S LARGEST LIZARD.

A TIRELESS PREDATOR, IT COVERS GREAT DISTANCES IN SEARCH OF FOOD.

THE PERENTIE TRACKS ITS PREY BY SIGHT AND BY DETECTING SCENT MOLECULES THAT IT PICKS UP ON ITS TONGUE.

[ BUDGIE CHIRPING ] [ CHIRPING ] [ CHIRPING ] [ CHIRPING ] [ CHIRPING ] [ SQUEAK ] [ ALL CHIRPING ] IN THE AIR, THEY'RE NOT NEARLY SO VULNERABLE.

SYNCHRONIZED SQUADRONS FLY LOW BETWEEN THE MULGA TREES -- THE COLORS ON THEIR BACKS CAMOUFLAGE THEM AGAINST THE GRASSES.

WHERE THE BUDGIES GO...

THE BIRDS OF PREY FOLLOW.

KITES, FALCONS, HARRIER HAWKS.

EACH HUNTER LOOKS FOR A WEAK LINK.

BUT IT'S NOT ALWAYS LIFE AND DEATH FOR AUSTRALIA'S PARROTS.

GALAHS SEEM TO HAVE PLENTY OF TIME FOR CLOWNING AROUND.

IN SOME YEARS, BUDGIES BREED UP INTO SUCH NUMBERS THAT THEY BECOME, FOR A TIME, AUSTRALIA'S MOST NUMEROUS PARROT.

ACCOUNTS BY THE EARLY SETTLERS TELL OF FLOCKS SO BIG THAT THEY BLACKENED THE SKY.

BUT THE GOOD TIMES CAN ONLY LAST FOR SO LONG.

AND AS THE COUNTRY DRIES OUT AGAIN, BREEDING COMES TO A HALT.

HAVING RAISED SEVERAL GENERATIONS, THE BUDGIES DISPERSE, RESUMING THEIR NOMADIC LIFE IN THE DESERT, WAITING FOR THE NEXT BIG RAINS...

WHENEVER THAT MAY BE.

IN CONTRAST TO THE UNPREDICTABLE DROUGHTS OF THE INTERIOR, THE SEASONS ALONG THE SOUTHERN EDGE OF AUSTRALIA ARE FAR MORE REGULAR.

IN WINTER, ANTARCTIC BLASTS OF COLD AIR BRING SNOW TO AUSTRALIA'S HIGHEST MOUNTAINS.

WOMBATS CAN FORAGE IN ANY WEATHER.

BUT IT'S NOT GREAT WEATHER FOR PARROTS.

THERE IS ONE THAT MANAGES TO SURVIVE ABOVE THE SNOW LINE.

GREEN ROSELLAS FUEL UP ON ALPINE BERRIES AGAINST THE WINTER BLIZZARDS.

[ CHIRPING ] [ CHIRPS ] DOWN AT SEA LEVEL, THE COLD FRONTS BRING GALE FORCE WINDS.

GREAT FOR SURFERS...

BUT TREACHEROUS FOR ALMOST ANYTHING ELSE.

IF YOU'RE A ROCK PARROT, YOU MUST LEARN TO LIKE YOUR PLANTS HEAVILY SALTED.

LIVING IN THE SALT SPRAY ZONE IS NOT AN EASY LIFE, BUT THESE HARDY PARROTS ARE TOUGH CUSTOMERS.

THINGS GET A LITTLE EASIER IN THE NEARBY COASTAL HEATH.

THIS ENVIRONMENT IS RICHER, ATTRACTING GANG-GANG COCKATOOS.

LIKE MOST COCKATOOS, GANG-GANGS ARE LEFT-FOOTED... GRIPPING ONTO THEIR WIND-BLOWN PERCH WITH THEIR RIGHT LEG, WHILE HOLDING THE SEEDPOD WITH THEIR LEFT.

[ CALLING ] [ BIRDS CALLING ] YELLOW-TAILED BLACK COCKATOOS ALSO FAVOR THEIR LEFT FOOT WHEN TACKLING THE LARGE SEED-BEARING CONES OF THE BANKSIA TREE.

IT'S A TRICKY OPERATION THAT COMBINES BRUTE FORCE TO SLICE THROUGH THE TOUGH EXTERIOR AND A DELICATE TOUCH TO EXTRACT AND SHELL THE SEEDS THAT LIE WITHIN.

BUT THE VERY PLANTS THAT THESE PARROTS NEED TO SURVIVE MUST BE BURNED IN ORDER TO REGENERATE.

ALL THIS TAKES IS A THUNDERSTORM.

AND THE AUSTRALIAN BUSH BURNS ASTONISHINGLY FIERCELY.

BANKSIA FRUITS NEED INTENSE HEAT TO RELEASE THEIR SEEDS.

HAKEA CONES SPLIT.

GUM NUTS DROP TO THE FOREST FLOOR.

OIL IN THE EUCALYPTUS LEAVES IS AS EXPLOSIVE AS GASOLINE.

NO OTHER CONTINENT BURNS SO DRAMATICALLY AS AUSTRALIA.

SOME FIRES CONSUME MILLIONS OF ACRES.

BUT WITHIN HOURS, CURRAWONGS ARE POKING THROUGH THE ASHES.

AND CRIMSON ROSELLAS THAT SURVIVED THE INFERNO ARE FEASTING ON ROASTED EUCALYPT SEEDS.

JUST A FEW DAYS LATER, EUCALYPTS ARE SENDING OUT GREEN SHOOTS.

WITHIN A FEW YEARS, THE FORESTS RECOVER.

AND THERE'S PLENTY OF FOOD.

SO IT'S TIME FOR CRIMSON ROSELLAS TO START BREEDING AGAIN.

WITH THEIR BRIGHT PLUMAGE, PARROTS SEEM TO BE SCREAMING OUT TO POTENTIAL PREDATORS, "FREE FOOD!

COME AND GET IT!"

BUT WHETHER YOU'RE A BUDGIE, AN ECLECTUS, A ROSELLA, OR JUST ABOUT ANY OTHER PARROT, YOU HAVE TO TAKE COLORFUL RISKS IN THE MATING GAME.

[ ACCORDION PLAYING ] SOMETIMES YOU CAN HAVE THE BEST OF BOTH WORLDS.

THESE GAUDY BIRDS ARE, IN FACT, SAFELY CAMOUFLAGED BY THEIR LEAF-LIKE SHAPE AND GREEN BACKS.

ALTHOUGH THEY HAVEN'T QUITE MASTERED A DISGUISE FOR THE AUSTRALIAN SUBURBS.

EVER SINCE AUSTRALIANS STARTED PLANTING NATIVE TREES IN THEIR CITIES, IT'S AN "ALL YOU CAN EAT BUFFET."

AND PARROTS HAPPILY ACCEPT THE INVITATION.

SOME OVERSTAY THEIR WELCOME.

WITH TOO MUCH TIME ON ITS HANDS, THIS COCKATOO POKES AROUND AN ELECTRIC INSULATOR.

WHILE THE MANIACAL CORELLA WILL ATTACK EVERYTHING IN ITS PATH...

EVEN TARMAC.

AND THEN...

THE NEIGHBOR'S LAWN.

BUT SUCH DESTRUCTIVENESS IS MINOR COMPARED WITH WHAT THEY DO TO FARMERS.

AND COCKATOOS TAKE FULL ADVANTAGE OF MODERN AGRICULTURE.

A GENERATION AGO, LAKELAND WAS OPENED TO INTENSIVE FARMING.

IT WAS IDEAL COUNTRY FOR MAIZE AND PEANUTS.

AND AS THE CROPS GREW, THE SULPHUR-CRESTED COCKATOOS MOVED IN.

IN JUST A WEEK, THE BIRDS CAN INFLICT TENS OF THOUSANDS OF DOLLARS' DAMAGE TO THE MAIZE OF FARMER DARREN HOSKINS.

[ WHISTLES ] Man: THE NUMBERS HAVE BRED UP OVER THE YEARS.

THE MAIN REASON FOR THAT IS, IN THEIR NATURAL HABITAT, THEY HAVEN'T GOT A GOOD AMOUNT OF FOOD ALL YEAR ROUND.

WHERE IN THE VALLEY HERE IN LAKELAND -- EVEN IN THE DRIEST PART OF THE YEAR IN AUGUST, SEPTEMBER, WHEN IT'S EXTREMELY DRY -- THERE'S STILL CROP RESIDUE ON THE GROUND, AND THE BIRDS HAVE GOT TO FEED ALL YEAR ROUND.

WITH THAT, THEY CAN CONTINUE TO BREED 12 MONTHS OF THE YEAR, NO PROBLEMS AT ALL.

THERE'S FOOD AND THERE'S WATER HERE ON HAND, SO THEY'VE GOT IT LAID ON.

THEY THINK IT'S TERRIFIC.

Abraham: WHEN THEY'VE FINISHED WITH THE MAIZE, THE COCKIES HEAD FOR THE PEANUT FIELDS, WHERE THEY PICK APART THE HAY BALES.

[ ALL CALLING ] RED-TAILED BLACK COCKATOOS JOIN IN THE FUN.

SO HOW DOES THE FARMER TRY TO CONTROL THEM?

Hoskins: BASICALLY JUST DRIVING AROUND AND SHOOTING AT THEM WITH A HIGH-POWERED RIFLE.

JUST THE NOISE ALONE IS ENOUGH TO SCARE THEM, OR EVEN TOOTING THE HORN.

BUT IT'S A FULL-TIME JOB FOR TWO TO THREE MONTHS OF THE YEAR, TRYING TO STOP THEM.

BASICALLY ALL YOU'RE DOING IS JUST DRIVING AROUND, FOLLOWING THE COCKATOOS FROM ONE PADDOCK TO ANOTHER UNTIL THE DAY WARMS UP.

IT GETS TOO WARM FOR THEM, SO THEY GO BACK AND ROOST IN THE TREES.

THEN THEY COME BACK AGAIN AND COMMENCE TO FEEDING.

AND WE COMMENCE TO CHASE THEM AGAIN, WHICH IS BLOODY ANNOYING.

[ LOADS RIFLE ] [ GUNSHOT ] [ GUNSHOT ] [ GUNSHOT ] Abraham: FARTHER SOUTH, IN THE WHEAT COUNTRY, IT'S A DIFFERENT COCKATOO, BUT IT'S THE SAME STORY.

IN SMALL DOSES, LITTLE CORELLAS ARE A DELIGHTFUL AND ENTERTAINING BIRD.

BUT WHEN FLOCKS OF UP TO 30,000 MARAUDING BIRDS DESCEND ON YOUR HARVEST, YOU CAN UNDERSTAND WHY A FARMER MIGHT BE A LITTLE UPSET.

THE GRAIN IS STORED IN GIANT BUNKERS AND PROTECTED BY THICK CANVAS.

BUT THE CANVAS IS NO MATCH FOR THEIR SHARP BEAKS.

AND HAVING FEASTED ON THE MAIN COURSE, IT'S OFF TO THE NEAREST VINEYARD FOR A LITTLE DESSERT.

FOR LYCHEE FARMERS, RAINBOW LORIKEETS ARE THE ENEMY.

THE FARMERS SPEND EVERY DAYLIGHT HOUR PATROLLING THEIR ORCHARD TO KEEP THE BIRDS AT BAY.

LIKE CHILDREN WITH CUPCAKES, THEY TAKE A BITE FROM EACH ONE, SPOILING THEM FOR EVERYBODY ELSE.

FOR THE FARMER, IT'S A RACE TO SEE WHO GETS TO THE RIPEST FRUIT FIRST... AND THE BIRDS ARE WINNING.

BUT NOT ALL FARMERS ARE AT WAR WITH PARROTS.

A QUEENSLAND CATTLE STATION HAS BECOME AN UNLIKELY REFUGE FOR A RARE TURQUOISE BEAUTY.

THE GOLDEN-SHOULDERED PARROT.

[ CHIRPING ] LAST CENTURY, BIRD FANCIERS TRAPPED THESE PRIZED PARROTS AND ROBBED THEIR NESTS.

THIS PLUNDER LEFT THE SPECIES HANGING ON BY A THREAD.

TO MAKE MATTERS WORSE, THESE PICKY PARROTS HAVE VERY PARTICULAR LIFESTYLE REQUIREMENTS.

FOR STARTERS, A BREEDING COUPLE NEEDS AN AIR-CONDITIONED TERMITE MOUND TO BURROW INTO AND MAKE A NEST.

THEY'VE MADE SUE SHEPHARD'S CATTLE PROPERTY HOME.

AND EVERY BREEDING SEASON FOR 30 YEARS SHE'S BEEN RIDING HUNDREDS OF MILES, CHECKING EVERY MOUND FOR CHICKS.

IN HALF THE OCCUPIED MOUNDS, SUE HAS FOUND THE NEST FLOOR COVERED WITH A GRUB THAT IS UNIQUE TO THE NESTS OF GOLDEN-SHOULDERED PARROTS.

THE GRUB BELONGS TO A MOTH THAT SYNCHRONIZES THE HATCHING OF HER BABIES WITH THAT OF THE CHICKS.

THE GRUBS EAT THE CHICKS' POO -- WHICH SEEMS TO SUIT EVERYONE.

MEANWHILE, THE CHICKS' PARENTS GO OUT LOOKING FOR FOOD TOGETHER.

WHEN THEY RETURN, DAD FLIES TO THE MOUND TO CHECK THAT ALL IS SAFE... [ CHIRPS ] AND TO LET THE YOUNG ONES KNOW THAT IT'S MEALTIME.

HE STANDS GUARD WHILE THE FEMALE COMES DOWN TO FEED THE CHICKS.

AN EXHAUSTING SCHEDULE WHEN YOUR CHICKS NEED FOUR OR FIVE MEALS A DAY.

DAD'S JOB IS TO COAX THE 5-WEEK-OLD CHICKS OUT OF THEIR COSY NEST AND INTO THE BIG, BAD WORLD.

IT'S THE DRY SEASON, WHICH MEANS IT'S HARD FOR THE YOUNG BIRDS TO FIND FOOD IN THE THICK GRASS.

SO SUE HELPS NATURE ALONG, BURNING THE BUSH AND EXPOSING THE NEXT MEAL.

SUE'S PROPERTY IS A HAVEN FOR THE GOLDEN-SHOULDERED PARROT.

AND HER EFFORTS MAY BE THE ONLY THING STANDING BETWEEN THEM... AND EXTINCTION.

EVEN FARTHER NORTH, IN THE REMOTE WOODLANDS OF CAPE YORK PENINSULA, THERE'S A PARROT THAT'S INTRIGUED SCIENTISTS FOR A CENTURY.

STEVE MURPHY CAME HERE AS A YOUNG BIOLOGIST 10 YEARS AGO.

HIS QUEST WAS TO UNLOCK THE SECRETS OF THE WORLD'S MOST SPECTACULAR COCKATOO -- THE PALM COCKATOO.

FEW PEOPLE HAVE EVER SEEN THIS BIRD.

Murphy: LOOK HERE, HERE HE COMES.

Abraham: THE PALM COCKATOO DATES BACK TENS OF MILLIONS OF YEARS, TO WHEN AUSTRALIA WAS COVERED IN RAINFOREST.

HE'S THE GRANDDADDY OF THEM ALL.

LITTLE WAS KNOWN OF THIS MYSTERIOUS BIRD UNTIL STEVE MURPHY BEGAN HIS STUDY.

[ CROWING ] AND THE ONLY WAY TO FIND THEM IN THIS RAINFOREST IS TO MIMIC THEIR CALLS.

[ MURPHY MIMICS CALLS, COCKATOO RETURNS CALL ] Murphy: THEY'VE GOT A HUGE REPERTOIRE OF CALLS THAT THEY USE IN DISPLAY.

[ CALLING RESEMBLES "HELLO" ] THE HELLO CALL THEY MAKE IS PART OF THE DISPLAY -- IT SEEMS TO BE MADE ALMOST AS IF THEY'RE SAYING HELLO TO THEIR PARTNER OR THEIR NEIGHBORING COCKATOOS.

Abraham: UNLIKE OTHER COCKATOOS, PALM COCKATOOS DON'T LIVE IN FLOCKS.

THEY PAIR UP WITH A MATE, AND SEEM TO STICK WITH THEM FOR LIFE.

AND THEY CAN LIVE FOR UP TO 90 YEARS.

ONE COCKATOO IN CAPTIVITY HAD HER FIRST CHICK AT 54.

BUT TO GET THE GIRL, THE MALE MUST BE A MAN OF PROPERTY, WITH A PORTFOLIO OF GOOD NESTING HOLLOWS.

AND IF HE WANTS ANY CHANCE OF MATING, SHE MUST BE PERSUADED THAT HE'S STRONG ENOUGH TO BUILD HER SEVERAL MAGNIFICENT NESTS.

Murphy: ALL THE ELEMENTS OF A PALM COCKATOO DISPLAY ARE DESIGNED TO DRAW ATTENTION TO THAT MASSIVE BEAK.

THE BLUSHING OF THE CHEEK PATCH, THE WING SPREADING, WHICH MAKES THEM BIGGER -- IT'S ALL DESIGNED TO SHOW OTHER COCKATOOS THAT THEY'RE STRONG, AND THE PINNACLE OF THEIR STRENGTH IS IN THEIR BEAK.

ESSENTIALLY, HE IS TRYING TO PROVE THAT HE IS A BLUE CHIP INVESTMENT, AND THAT SHE CAN FEEL COMFORTABLE PUTTING ALL HER EGGS IN HIS BASKET.

[ CALLING ] Murphy: THEY JOIN UP EVERY MORNING AND AFTERNOON AT THESE NEST HOLLOWS.

AND THEY CATCH UP ON THE DAY'S EVENTS, AND IT REALLY DOES SOUND LIKE YOU'RE LISTENING TO AN OLD MARRIED COUPLE SOMETIMES.

I MEAN, THE ANALOGY CONTINUES.

IT'S JUST LIKE HUMANS AND THE PRIDE THAT HUMANS HAVE IN THEIR HOUSES.

PALM COCKATOOS ARE EXACTLY THE SAME.

BUT THE MOST AMAZING DISPLAY OF ALL IS WHEN MALES BRING BACK TO THE NEST A SMALL STICK, AND THEY ACTUALLY DRUM ON THE SIDE OF THE NEST.

MAYBE IT'S BECAUSE PALM COCKATOOS LIVE SO LONG THAT THEY HAVE TIME TO LEARN SO MUCH.

BUT IT'S A RARE THING ANYWHERE IN THE ANIMAL WORLD TO SEE A TOOL BEING USED QUITE THIS DELIBERATELY.

[ THUMPING ] Murphy: I THINK IT'S VERY LIKELY THAT THE FEMALE WATCHES THESE DRUMMING DISPLAYS AND CAN TELL SOMETHING ABOUT EITHER THE MALE OR THE NEST TREE AT WHICH HE'S PERFORMING.

YOU KNOW, THERE'S SOMETHING THAT SHE'S PICKING UP IN THE WAY THAT THE DRUMMING SOUND RESONATES INSIDE THE HOLLOW.

WE DON'T REALLY KNOW, BUT, I MEAN, SHE WATCHES VERY INTENTLY.

Abraham: THE CHOOSY MALES WILL TRY 2 OR 3 DIFFERENT DRUMSTICKS BEFORE THEY SETTLE ON ONE THEY REALLY LIKE.

Murphy: WHEN THEY ACTUALLY PERFORM THE DRUMMING DISPLAY AT THE NEST, IT DOES SEEM TO HAVE A RHYTHM.

[ CALLS, THUMPING ] BUT WHEN HE'S FINISHED WITH IT, HE'LL OFTEN SIT AT THE EDGE OF THE HOLLOW AND SPLINTER UP THE STICK, AND ADD IT TO THE NESTING PLATFORM THAT'S INSIDE THE HOLLOW.

Abraham: IF THE FEMALE IS IMPRESSED, SHE WILL WALK DOWN AND JOIN HIM AT THE ENTRANCE OF THE NEST, TO SEE IF IT'S GOOD ENOUGH TO BREED IN.

WITH THE HOLLOW APPROVED, THEY CAN FLY OFF TO HAVE A MORNING SNACK.

THE LOCAL BIRDS GATHER AT TREES THAT ARE FRUITING.

Murphy: THAT REALLY POWERFUL BEAK THAT PALM COCKATOOS HAVE, WHICH IS BY FAR THE BIGGEST BEAK OF ANY OF THE COCKATOOS, IT ALLOWS THEM TO EAT FOODS THAT OTHER COCKATOOS, AND OTHER ANIMALS IN GENERAL, JUST SIMPLY CAN'T ACCESS.

I THINK PALM COCKATOOS ARE VERY INTELLIGENT.

YOU'VE ONLY GOT TO WATCH A PAIR COURTING AT THEIR NEST, OR A MALE FASHIONING A DRUMSTICK, TO REALIZE THAT THERE IS COMPLICATED THOUGHT GOING IN THAT BIG HEAD OF THEIRS.

Abraham: OF COURSE, THESE REGAL PALM COCKATOOS ARE NOT THE ONLY CLEVER ONES -- ALL PARROTS ARE SMART.

BUT THESE ARE THE OLDEST, THE CLOSEST LIVING RELATIVES OF THE ANCESTRAL COCKATOOS THAT FIRST EVOLVED IN AUSTRALIA SOME 20 MILLION YEARS AGO.

FROM THESE NORTHERN, TROPICAL RAINFORESTS, PARROTS BEGAN WINGING THEIR WAY ALL ACROSS THE CONTINENT, ADAPTING TO EVERY CORNER OF THE COUNTRY.

THERE'S NO GREATER RICHNESS AND DIVERSITY OF PARROTS ANYWHERE THAN HERE, IN AUSTRALIA -- THE LAND OF OZ.