A Year on Planet Earth (2022-…): Season 1, Episode 2 - Spring - full transcript

In March, as the northern hemisphere starts to face the sun's rays the transformation is enormous, the great melt begins, and new life erupts.

'The sun.

'15 million degrees Celsius
at its core.

'Too close,

'and you burn.

'Too far...

'..you freeze.

'But at just the right distance,

'you get this.

'A living, breathing world.

'No other planet
in the known universe

'experiences seasons
like our planet, Earth.'



By the beginning of March,

we in the north
are turning towards the sun...

'..and winter snow begins to melt.

'Just a little at first.

'Then more and more.'

Until the flow of water
becomes truly staggering.

Every year, the returning sun

melts over ten million square miles
of snow

in the Northern Hemisphere.

'Allowing the land to reawaken...

'..and bringing new life.

'While in the Southern Hemisphere,
life braces itself

'for far tougher times ahead.

'In more than 60 locations
across the globe,



'we follow the world's
most spectacular animals...

'..and reveal the struggles...

'..and opportunities

'of spring.

'The most magical part
of our journey around the sun.

'This is going to be
an extraordinary day.

'No matter where you are
in the world...

'..there will be
12 hours of daylight...

'..and 12 hours of darkness.

'The spring equinox has arrived.

'Incredibly, there is one animal

'that can detect
this unique celestial moment.

'A leatherback turtle.

'She has a translucent spot
on her head

'that acts like a skylight,

'letting light
shine through her skull,

'directly onto her brain.

'And now, after two decades
of wandering the oceans,

'it compels her to return
to the beach where she hatched...

'..and lay eggs of her own.

'As graceful as they are in water,

'leatherbacks are poorly-adapted
for moving on land.

'The largest turtles in the world,

'over a half a tonne,

'and as a big as a two-seater sofa.

'Every inch
is won by extreme labour.

'It's going to be a tough night.

'Her eggs are very sensitive
to temperature.

'To prevent them from overheating,
she must dig deep.

'Finally, after more than an hour,
her nest is ready.

'She lays around 80 eggs...

'..each slightly bigger
than a golf ball.

'Now safely buried,

'they will hatch in two months.

'But she won't be here
to see her babies emerge.

'Exhausted,
she must recoup her energy

'by going to feed
in the richest part of the ocean...

'..which now lies
thousands of miles north.

'As the sun moves further over
the Northern Hemisphere,

'days now become longer than nights.

'And light fuels growth.

'The land bursts with colour.

'And surprisingly,

'some of the most spectacular
spring blooms of all

'are found right in the middle
of the desert.

'Since December,

'day length here
has increased by two hours.

'The solar energy reaching
the ground has almost doubled.

'And with the Earth still moist
from winter rains,

'conditions for growth are perfect.

'And now these nectar-laden flowers

'attract new life from miles around.

'Including one of the most beautiful
birds in the desert.

'A male Costa's hummingbird...

'..preparing for
his busiest time of the year.

'Without nectar, he would die
of starvation within a few hours.

'Hummingbirds have the fastest
metabolisms of any animal.

'His tiny heart
beats more than ten times a second.

'And just a few yards away

'is someone
that can make it beat faster still.

'A female Costa's hummingbird.

'She may look a little drab...

'..but she is
the object of his desire.

''The only problem is,

'despite his fancy feathers,
she doesn't appear to fancy him.'

'Thankfully,
he has a trick up his sleeve.

'One of nature's most extraordinary
courtship displays.

'Best admired with a full frontal.

'Positioned at just the right angle
to the sun...

'..with feathers splayed...

'..he is absolutely dazzling.

'Having a purple octopus
waved in your face

'might not be your thing,

'but the perfection of his plumage
shows his quality.

'And it works for her.'

'In just over a month,

'her chicks will have hatched,
grown up and flown the nest.

'Spring comes early in the desert,
and it doesn't last long.

'But further up
in the Northern Hemisphere,

'it's only just begun.

'The greatest baby boom on Earth
is still to come.

'In the north,
spring is now taking hold.

'The strengthening sun

'fuels billions of tonnes
of new plant growth.

'It sends a pulse of energy
coursing through the food chain,

'triggering an enormous baby boom.

'A surge of easy-to-catch prey

'makes this the ideal time

'for hunters
to raise their families, too.

'But closer to the equator,

'predators aren't having it so easy.

'East Africa,

'home to the planet's
greatest population

'of large carnivores.

'Five months ago,

'this landscape
was a predator's paradise.

'A million wildebeest.

'300,000 zebras.

'And 200,000 gazelles.

'Nearly all gone.

'And the great migration
won't return until summer.

'Now, only the locals remain.

'Experienced and wary.

'Spring can be a tough time
for a cheetah mum.

'Her two six-month-old cubs
need to be fed every day

'or they'll begin to starve.

'But she must pick her moment...

'..conserve her energy.

'The cubs have a different agenda.

'Playing is how they learn which
animals are impossible to catch.

'And which ones fight back.

'With practice,
they will be able to accelerate

'faster than most sports cars...

'..and reach speeds of up to 65mph.

'But not yet.

'Right now,
they're just being a pain in the...

'..tail.

'Enough with the play.

'It's time to go to work.

'As far as we know,

'cheetahs are the fastest
land animals to have ever existed.

'They can execute turns

'at speeds that would break the legs
of other animals.

'But like
any high-performance athlete,

'success or failure is separated
by the tiniest of margins.

'The hunter's dinner
is never guaranteed...

'..especially at this time of year.

'In many ways,
the prey have it easier.

'Their food grows everywhere.

'But it is dependent
on one crucial resource.

'Water.

'Since winter,
the tropical rain band

'has been steadily moving up
the continent...

'..forming wherever the sun shines
hottest on the Earth's surface.

'It brings life
to the dry lands of Africa.

'But as the rains move north...

'..further south...

'..conditions are becoming critical.

'The water holes are shrinking...

'..getting crowded...

'..and more dangerous.

'Even the elephants are vulnerable.

'Especially the youngsters.

'The old matriarch leader
of this group

'knows it's time to move on.

'She has made many journeys
in search of water

'in her 50 years,

'and can even remember routes made

'during extreme droughts
decades ago.

'And now this four-month-old baby

'must learn the way
as he begins his first migration.

'Indeed, much of
an elephant's behaviour is learned.

'From birth to adulthood,
their brains almost triple in size,

'the greatest increase
of any animal apart from us.

'The good times are over.

'Ahead, only a thirsty,
gruelling march.'

'The red-billed quelea
are also heading off.

'They follow the rains
and the pulse of fresh grass seed.

'And they do so in their millions.

'The most abundant wild bird
in the world.

'The key to their success
is a super-fast breeding cycle,

'little more than three weeks
from laying eggs to chicks flying.

'Ready to leave
when conditions get tough.

'Not everyone has that option.

'In the far south,
the darkness is creeping in.

'The sun sinking lower.

'The land growing colder.

'This four-month-old
king penguin chick

'is stuck here.

'She won't be ready
to leave the island

'for another eight months.

'So she must prepare
for the coming cold.

'Since hatching, she's grown
from a tiny, naked chick,

'weighing less than 250g,

'into this plump, downy youngster
of nearly 12 kilos.

'Just as well - it's the coldest day
of the year so far.

'And something new and strange
is happening.'

'Curiosity gets the better of her.

'The nasty side of town.

'The source
of all this flying fluff?

'Not snow.

'Manky, moulting macaroni penguins.

'And there's something else here.

'Monsters.

'These are giant petrels.

'Three feet tall,
and as heavy as a Christmas turkey.

'The stress of moulting
makes some macaronis weak.

'But if you show weakness here...

'..there is no mercy.'

'Giant petrels
don't miss any opportunity.

'Against these relentless killers,
a chick doesn't stand a chance.

'And she's just been spotted.

'When a giant petrel
sizes you up like this,

'it's time to get out of here.

'Her nemesis is coming for her.'

'But the giant petrel
has underestimated the kings.

'Twice as big as the macaronis,
they can stand up to this bully.

'It's all too much
for the giant petrel.

'Finally, the chick can relax.

'But not too much.

'Soon, her parents
will be gone for weeks,

'even months, on end.

'As the water gets colder,

'the ocean currents shift

'and feeding areas
move further away.

'She will grow hungrier, weaker...

'..and she'll be alone.

'While conditions in the south
grow harsher...

'..the Northern Hemisphere
is in the full flush of spring.

'And here,
in this seasonal rainforest,

'the fresh growth
feeds all kinds of animals.

'Including one of the most striking
monkeys on the planet.

'Red-shanked doucs.

'Timed with the burst of
fresh spring leaves and flowers,

'these doucs are having
a baby boom of their own.

'Only four years old,

'this is the youngest mum
in the community.

'And this is her first baby.

'Just days old.

'Right now,
it's a worrying time for Mum.

'Newborns make easy targets...

'..for all kinds of predators.

'But too much protection
can be stifling.

'He needs to learn key skills,

'like how to move
through the forest.

'Doucs make some of
the longest leaps of all monkeys,

'frequently exceeding ten metres.

'You can't do this
without a lot of practice.

'Sometimes, a mum has to let go.

'We see spring as a time of relief
after a long winter.

'Yet for many animals,
this is a time of great stress.

'Never will their babies
be more needy and more vulnerable.

'And never will parents
have to be more vigilant.

'But all a mum can do
is take it one day at a time.

'At least she's bringing up baby

'in the relative comfort
of the tropics.

'A little further north,
just beyond the Himalayas,

'it's a different story.

'The Tibetan Plateau.

'Covering nearly
a million square miles,

'and averaging
over 4,000 metres high,

'it's the largest
and highest plateau in the world.

'With little more than
half the oxygen at sea level,

'the air leaves you gasping.

'Winter temperatures can plummet
to minus 20 degrees Celsius.

'Not many animals
have adapted to life up here.

'This is one of the few.

'A Tibetan fox.

'A mere 2.5 million years

'set it apart from our red fox.

'Yet it's enough to have evolved
an extraordinarily wide gape.

'An adaptation for a diet consisting
almost entirely of these animals.

'Thanks to a surge
of spring breeding,

'plateau pika are everywhere.

'But they have
hundreds of boltholes.

'To catch one, you have to be...

'..patient.'

'A lot of work
for such a small snack.

'And she's not even going to eat it.

'It's for her three
eight-week-old cubs.

'In fox families,

'fathers usually stick around
to help.

'But Dad hasn't been seen for weeks.

'Up here, conditions are so harsh,
lives are often cut short.

'Keeping the family fed
is now a real struggle.

'By the time the cubs are up...

'..Mum's already out hunting.

'All this play is hungry work.

'But for some reason,

'breakfast is late.

'Constantly sprinting after prey

'over potholed ground

'has taken its toll.

'An injury as serious as this
could stop her hunting.

'And that means starvation
for the whole family.'

'Though clearly in pain,
Mum is off hunting again.

'With cubs to feed,
she has no choice.

'But sometimes, adversity brings out
the best in you.

'She's found her A-game.

'Perhaps her luck is returning.

'Thanks to Mum's
extraordinary determination,

'the cubs
should keep growing strong.

'With so many mouths to feed,

'spring can be
the most challenging time of year.

'This cheetah mum...

'..desperately needs
a change in fortune.

'No matter how hard she tries...

'..it always ends in frustration.

'Mum is exhausted.

'She can't afford any more failures.

'Hyenas will kill cheetah cubs.

'They're too big to beat in a fight.

'The whole family
has to be very careful.

'All she can do

'is stay by her cubs
and hope the danger passes.

'The threat from lions and hyenas
is constant.

'But she can't hide forever.

'Her family needs to eat.

'A male impala.

'Cheetahs usually avoid
such large, heavily-armed prey.

'The risk of injury
is just too high.

'But not for this mum.'

'For the first time,
her cubs actually help.

'Around 80% of cheetah cubs here

'succumb to predators or starvation

'before the reach
their first birthday.

'Her cubs
still have a long way to go...

'..but with every kill,

'every passing day,

'their chances improve.

'Spring in the north
is drawing to an end.

'But here, on this beach,

'it still has one final wonder
to offer.

'For eight weeks...

'..the leatherback eggs

'have been gently incubated
by the sun.

'Now the baby turtles
are beginning their own journey.

'But everything will depend on
the next few minutes.

'Black vultures
have been waiting for this moment.

'Their mum's sacrifice,

'her toil on the beach,

'may come to nothing.

'But if this hatchling
can make it to the sea,

'the odds of reaching adulthood
rise dramatically.

'He's passed his first trial.

'With luck, he may go on
to live for over 50 years...

'..and cover
tens of thousands of miles.'

Within a month,

some of the leatherback turtles
that nested in Trinidad

could have come
as far north as here,

in Iceland, to feed.

'Soon, the sun
will deliver more energy here

'than the hottest part
of the tropics.'

We're about to begin summer.

The hottest, most intense,

and most vibrant part

of our journey around the sun.

'Right across the globe...

'..animals will face
new challenges...

'..and unique opportunities...

'..during the most extreme season

'on planet Earth.'