Crowded Skies Life in the Air

The sky is one of the most challenging places to live.

But all across the world, extraordinary animals do

something we can only dream of...

..take to the air.

Some spend their whole lives up here.

Others only visit for a moment.

We'll discover how many incredible animals thrive in the sky...

..and what clever tricks they use to get airborne.

With the help of some specially trained animals,

the latest technology and special effects techniques,

we'll reveal brand-new discoveries

that explain how animals take to the skies.

This is Life In The Air.

Right now, there are billions of creatures

living in the three miles of air above our heads...

without us evening knowing they're up here.

They've overcome gravity,

they've mastered flight and now they live their lives up here,

making the most of the opportunities the skies have to offer.

There are over a thousand species of mammal

and over tens of thousands of species of birds up here.

The biggest numbers are the smallest players.

And the closer you look, the more of them you see.

Insects, trillions of them,

so many that 98% of everything that flies is an insect,

and most of them don't even have names.

The air above us is more crowded and more dangerous than you might think.

Predators are everywhere.

At every level, the skies are teeming with life.

There are thousands of creatures using

the skies as super-highways,

travelling huge distances

to find food or to migrate.

Butterflies.

Even ladybirds.

Over a kilometre above our heads there are moths

speeding by at 80 kilometres an hour.

But what happens when so many lives collide?

How do animals compete with each other up here?

How do they win a mate?

How do they find food?

How do they hunt, and avoid being hunted?

Up here, animals are pushed to the limits of what's possible.

Welcome to another world,

a world of intense competition,

of extreme lives in crowded skies.

The coast of South Africa is home to one of the most extreme

fliers in the natural world.

The Cape gannet has a unique way of beating the competition

when it comes to finding food.

The size of this island breeding colony

shows the richness of the seas around them,

enough to supply the tonnes of fish caught by these birds every day.

But it's how they catch fish that's so remarkable.

Here, the competition from other sea birds is intense.

Most can only catch fish when they swim close to the surface.

But there are richer pickings deeper down.

And that's what the gannets are after.

It requires an extreme form of flying that would kill most

other creatures.

Several kilometres from the gannets' colony,

a vast shoal of sardines is massing.

And 20,000 gannets are heading out after them.

But most of the sardines are several metres below the surface,

completely out of reach for the other sea birds.

So the gannets prepare to perform

one of the most dangerous flying stunts in the animal kingdom.

Climbing 30 metres above the surface,

they drop from the sky using gravity to accelerate...

Hitting the water at 100 kilometres an hour.

with the same force as a bullet fired from a handgun.

The impact should kill them.

At that speed, it's like hitting concrete.

So how can they possibly survive?

Less than a second before contact, they tuck in their wings and change

their shape, streamlining their body to slice through the water.

The gannets have air-filled pockets under the skin in their necks

and chests, thought to act like airbags to help

cushion their bodies from the impact of the water's surface.

But their technique must be precise.

If their shape isn't perfectly streamlined,

the impact of hitting the water would crush them.

The dive propels them down to where the fish are schooling

but they still have to catch them.

Exactly how they do that depends on a critical decision each bird

made the second before it dived.

In mid-air, the gannet has two choices -

to dive shallow or to dive deep.

A quick, shallow dive allows it to hit the water fast

and instantly snatch any fish near the surface.

But once under attack,

the sardines escape downwards, and the gannets must up their game.

..diving almost vertically to give them

the speed to reach 10m underwater in a few seconds.

Their extreme dive has taken them to an alien world,

far away from the competition from the other sea birds.

A world where wings become fins, feet become paddles...

Even their eyes change shape so that they can see underwater,

and special eyelids act like goggles.

They are the only birds down here, and they reap the reward.

Running out of breath, they return to their sky world

using the air trapped in their feathers

to carry them back to the surface.

Risking death to dive deep allows gannets to escape the competition

and find food for their families.

But using extreme flying to catch

food is not just a survival trick for gannets.

There's plenty of food out there

for the animals who can fly well enough to catch it.

An African skimmer goes fishing too, flying with such precision that the

lower part of its beak can feel for fish just below the surface.

If it snaps shut, it's caught a fish.

There's a fishing bat that expertly deploys its enormous clawed

talons as trawling fish hooks.

But bats had better watch out or they might become food themselves.

Falcons use quick reactions

and extreme control to catch fast flying bats in mid-air.

Food is not the only thing animals in the skies compete for.

When it comes to finding a mate, there are some creatures

who've taken this to a record-breaking extreme.

Meet the Anna's hummingbird.

One of California's finest.

He's no bigger than a ping-pong ball,

no heavier than a 20-pence coin,

but he's a record-breaking flying machine.

His wings pump at 2,500 times a minute.

His heart beats at 1,200 times a minute

and he can hover for well over an hour.

He needs to mate,

but he has to prove that he's fitter than the rest.

He has a problem.

There's another male vying for the female's attention,

and he's a record-breaking flying machine too.

Let the competition commence.

Aggression drives the intruder away.

But that in itself doesn't impress her enough.

Now he's going to have to pull off the flying stunt of his life.

First, he woos her to his performance arena with a song.

IT CHIRPS

Now he's got her attention,

the stage is set for this tiny bird to perform

the fastest courtship display ever seen in the animal world.

He climbs 30m above her...

Then for the grand finale, he dives straight at the ground.

That was it, over in a few hundredths of a second.

And again.

To see what he's doing, we need to slow things down.

This is much more than just high-speed flying.

By folding his wings in tightly, he mimics a missile,

travelling 20m and 400 times his body length every second.

At the last moment, he pulls up sharply,

pulling more Gs than a jet fighter pilot.

But it's not just the speed, the height or

the angle of his flight, it's all about serenading on the wing.

His tail is singing a sweet song with jet-fighter force.

The air screaming through his spread-out tail feathers makes them

vibrate in a very special way.

BUZZING

Slowed down, this is the sound they make.

BUZZING

BUZZING

It's far louder than any of his singing.

And the faster he dives, the better it sounds.

BUZZING

Who'd have thought that a sound like this...

BRIEF CHIRP

..or this... BRIEF CHIRP

..would make all the difference and see off the competition?

To her, it proves he's fit.

This bird boy-racer has won himself a mate by pushing

himself to the limit and proving he's got what it takes.

But he's not the only one who knows that a little showing off

can go a long way.

Aerial displays are a serious business.

The greater the effort, the more lasting the impression.

Meet the male spatuletail hummingbird.

It has to be said, with a tail like that,

he's already making quite an impression.

But to win over his female,

he'll need to hover and wave his enormous tail flags

at the same time.

It's such an endurance test,

every now and then, he needs to take a little rest.

With every leap,

this lesser florican is trying to prove he's fitter

than all the other males.

And today, just to make sure, he's going to do 500 of them.

In the dense jungles of Costa Rica,

there's little room for showing off.

So one amorous male woos a female

with an altogether more cunning tactic.

Meet the male glasswing butterfly.

He's got see-through wings precisely

because he doesn't want to stand out from the crowd.

There are just too many jungle predators around for that.

He too uses the air to show off,

but it's an aerial display like no other.

He's going to use the air to carry an irresistible message

to a female and to get her to come to him.

On his wings, he has little bunches of hair

loaded with his own distinctive pheromone perfume.

The perfume wafts through the trees carrying a specially coded message

invisible to others.

It tells the female who he is and how many poisonous plants

he's managed to eat.

Because he stores the poisons in his body

and uses them to show how distasteful he is to predators.

So, to a female checking out the males in the jungle,

it's good to have bad taste.

The secret message wafting invisibly through the jungle says,

"I'm here, I'm male and I taste worse than all the others."

She's hooked and follows the trail of his irresistible odour.

It's a clever trick,

the male attracts a female without attracting predators.

When it comes to finding a mate,

males will try anything that works to give them an edge.

And with the skies so full of competition,

it pays to be cunning like the glasswing.

But once animals have paired up,

it's not long before offspring arrive,

and they need looking after.

This is Oregon, USA.

Home to the kingbirds.

They're an ordinary looking couple working hard to raise a family.

But don't be deceived,

these birds are remarkable.

The male has picked the perfect home,

the air is thick with insects to eat,

but he'll have to work hard to catch them for his family.

He's agile enough to take insects on the wing, and that's no mean feat.

The top prize for a kingbird is this.

A big, juicy dragonfly.

They're more manoeuvrable than him,

and they're one of the fastest insects in the world,

topping 50 kilometres an hour.

But the kingbird is faster.

This is speed versus agility.

He'll work hard like this to feed his chicks

for nearly for nearly two months.

His commitment is total.

But his true colours are about to be revealed.

He's spotted danger in his neighbourhood.

CROWING

Ravens.

They'd kill his whole family in minutes given the chance.

He's going to have to defend his offspring.

Ravens are clever, and they're four times bigger than him.

But no-one is going to hurt his family.

As formidable as the ravens are,

the kingbird has an unexpected side to his character.

Sheer. Obsessive. Belligerence.

What he's about to do seems almost suicidal.

He manoeuvres into the raven's blind spot.

He hassles it, landing on its back, even stabs at its neck.

The raven could kill him.

But as long as he holds this position, he's in control.

Those superb acrobatic skills that helped him

chase down dragonflies are now being used to help keep his family safe.

Kingbirds will take on anything,

including large birds of prey.

They've even been seen having a go at low-flying aircraft.

A combination of spectacular flying agility and an almost

psychopathic attitude makes the skies above a kingbird nest

a little less crowded than they might be,

and the chicks, a little safer.

That's dedication.

The kingbird takes huge risks to give his young a flying start

in this competitive world.

But there's a tiny animal from Texas that takes parenthood

to an even greater extreme.

The phorid fly.

Smaller than a pin's head, she's a mother.

And right now, she needs to lay her eggs and secure a safe future

for her offspring.

But to do this,

she must face one of the most feared animals in Texas.

Fire ants.

In their thousands.

They have a vicious bite and a venomous sting.

They'll kill any insect that crosses their path.

But incredibly, these vicious predators aren't going to eat

the phorid fly's young,

the young phorid flies are going to eat them.

First, the mother must pull off one of the greatest daredevil

flying missions in the natural world -

she's going to lay her eggs on living fire ants.

She's going to have to do some serious precision flying,

or she'll be killed herself.

How she does it can only be fully understood

by watching in slow motion.

First, she hovers as close as possible to her victim

but just out of reach of the ants' jaws.

The risk is finely balanced, just a breath of wind and she's dinner.

Now she's ready to quickly deposit an egg in a chink

in the ant's armour, at a leg joint.

From start to finish, it takes just one sixtieth of a second.

Once attacked, the ants send out a chemical alarm to warn the others.

They hide, crowding under any available cover,

making it much harder for the phorid fly to get at them.

But she has over 100 eggs still to lay.

She's going to have to up her game and test her hovering skills

to the max if she's going to deliver her cargo successfully.

Her daredevil mission is accomplished.

But the story isn't over for the ants.

Inside each ant,

the fly larva has taken over the ant's mind,

reprogramming it to walk off like a zombie.

The ant finally dies safely away from its colony

where the fly larva can grow up in peace.

The ant's zombie body now becomes perfect phorid fly baby food.

For two weeks, the fly larva eats the ant from the inside.

A tiny new phorid fly stretches her wings for the first time.

Soon, like her mother, she'll fly her own mission impossible,

a hair's breadth from a fire ant's jaws.

At every stage of their lives, animals are doing what it

takes to stay ahead of the rest

to survive and raise a family.

But in our crowded skies,

they face competition from others at every turn.

With so many lives interacting, colliding and competing

and so much pressure to succeed,

animals have had to push their flying abilities to the extreme,

taking huge risks with their own lives.

Up here, it can be tough to find food...

..win a mate...

or secure a future for your offspring.

Life in the air is a life of intense competition.

And where there's competition,

there are animals who choose not to play by the rules.

Few are sneakier than an inhabitant of tropical seas

and islands around the world -

the frigate bird.

This pterodactyl-shaped bird has a curious problem.

Remarkably for a sea bird, its feathers aren't waterproof.

If it gets too wet, it'll sink and drown.

That's obviously not good for a bird that needs to catch fish.

So the frigate bird uses its unique flying speed

and agility to catch fish another, less honest, way.

It steals fish from others.

It's a flying pirate.

This time, its victim is a red-billed tropic bird.

The frigate bird is going to force it to give up its last meal,

and that means putting it under serious pressure.

The tropic bird is a superb flier,

but the frigate bird pirate is better.

His wings are unusually large, but his body remains light.

These two things combined deliver the most extraordinary

agility in the air.

The frigate bird can, in theory,

out manoeuvre any other sea bird in the world.

Perfect skills for a pirate of the skies.

But the tropic bird isn't going to give up its hard-earned meal easily.

When the tropic bird finally gives up its dinner,

the frigate bird is in precisely the right spot for the catch.

When it comes to aerial combat,

it takes a lot to beat this thieving pirate.

Our crowded skies are a competitive battle zone,

with tussles between species going on all the time,

as they've done for millions of years.

But just occasionally, the underdog fights back

and outsmarts its attacker.

Take this moth.

It can seem pretty incompetent in the air,

with weak and fluttery flight and a bad sense of direction.

It can blame that on its ancestors.

100 million years ago, insects had the night sky to themselves.

They didn't need to be strong fliers

because there wasn't much out there to get them.

But then along came new, intelligent,

highly-equipped creatures that could hunt them down easily.

They are the only mammals that have ever learnt to fly,

and many could see in the dark.

Bats.

Bats were onto something.

There was a great feast to be had in the night.

To a moth, this is a sophisticated, highly dangerous enemy.

A bat finds its prey using echolocation.

Literally, it locates using echoes.

You could say it sees using sound.

It sends out clicks into the air, as many as 200 a second.

If the clicks hit anything, they bounce back as echoes.

It's by listening to those echoes in the darkness a bat can pick

out its surroundings, even a moth.

As the bat approaches its victim, the clicks get faster,

creating a buzz of sound that helps it home in on its target.

These sounds all happen beyond our human hearing.

But we can see them as sound waves.

First searching.

Then approaching.

And then finally, the attack.

So a bat is a super flyer with added superpowers,

and that's hard to beat.

If they were going to survive, moths had to raise their own game.

Some of them began to hear the bats coming.

When they hear the buzz of an attacking bat,

these moths take evasive action.

They drop out of the sky.

Simple, but effective.

An arms race had begun between bats and moths,

each trying to out compete each other in the night sky.

Eventually, a race of super moths emerged.

Super moths like this tiger moth.

Its superpowers have only recently been explained.

The tiger moth can vibrate a tiny membrane under its wing.

This produces a special high-frequency sound

to confuse bats.

When a bat attacks,

the secret weapon is deployed.

The moth's special sound jams

the bat's echolocation system,

so it can't see with sound properly.

It's enough of a smokescreen

to allow the moth to escape,

leaving the confused bat to try and find another.

Every night, around the world, hi-tech aerial battles like this

take place with sophisticated weaponry,

changing the odds, as predator is pitched against prey.

Bat versus moth,

aerial competition that's been played out over millions

of years between billions of rivals,

where the tiniest advantage may make

all the difference in the fierce battles that rage in the skies.

If you're caught in a one-on-one life or death battle in the sky

and you don't have a secret weapon up your sleeve,

you'd better be able to out-fly your assailant.

As a lone flyer, you have few other options.

But there is one way to beat even the best aerial hunter.

And that's teamwork.

A group is almost impossible to sneak up on without being noticed.

But there are other reasons that animals move together like this.

Predators can only chase one of you at a time.

The way they see has evolved to focus on just one animal.

Faced with a swirling flock, they struggle to focus.

It's information overload.

Flocking is a really effective strategy,

and many birds do this all over the world.

But how can they fly so fast

and so close to each other without colliding?

And who is deciding where to go?

Take starlings.

Their flocking behaviour is world-famous,

it even has a special name - a murmuration.

Confusing to a predator,

it's one of the most breathtaking sights in nature.

Hundreds of thousands of individual birds are moving as one,

and amazingly, there's no single bird in charge of the plan.

Just how these complex aerial displays work has baffled us

for centuries and has only just recently been explained.

Remarkably, the truth about their complexity is rather simple.

To understand how it works, imagine you could fly

into a giant flock alongside one single starling.

How she flies is all to do

with what her seven closest neighbours are up to.

As the flock moves,

those seven might change,

but the principle stays the same.

Every starling in the flock is following three simple rules.

Firstly, as you fly, steer towards each other.

Secondly, if any of your seven neighbours turn, then you turn.

Finally, don't crowd each other.

Amazingly, that's all there is to it.

Inside a flock, individual birds are making these simple decisions

in hundredths of a second, again and again.

It's enough to confuse a predator.

And when half a million birds do it altogether,

the results are spectacular.

So how do we know precisely that this incredible spectacle is

the result of just three simple rules and seven near neighbours?

The answer lies in what you see here.

This swirling mass of birds doesn't actually exist in the natural

world, it exists inside a computer.

It's a computer simulation, with virtual birds

created by scientists trying to work out how flocks work.

Incredibly, this computer-generated flock looks

and behaves exactly like the real thing.

Each bird is following its seven neighbours

and using the same three rules.

Watch a real flock anywhere on earth...

..and it will be working in exactly the same way.

In our crowded and competitive skies,

this surely is the ultimate defence against an airborne predator

and one of nature's greatest flying stunts.

Our skies are teeming with life,

every creature trying to find its way and to survive.

If you can overcome the challenges of life in the air,

there are great opportunities to be had.

It's all about finding your place in the sky

and picking a winning strategy.

For some, it's enough just to beat gravity for a few seconds.

For others, it means taking a leap of faith.

Extraordinary specialist techniques might just give you an edge.

All these animals have skills we humans can only wonder at.

Every time an animal takes to the air,

it seems to be performing its own personal miracle.

Defying gravity to live in a world

that we are only just beginning to understand.

In Life In The Air, the team's mission was to reveal the incredible

abilities of airborne animals in more detail than ever before.

To do it required some extreme perseverance

and a range of approaches.

Some animal stars could be filmed in controlled conditions,

allowing the team to move their cameras alongside them.

Others could only be filmed on their own terms out in the wild.

Blimey!

The most challenging filming in the wild involved the smallest

and fastest of flyers - the Anna's hummingbird.

To film their record-breaking dive,

the team needed a secret weapon - cameraman Barrie Britton.

Filming birds requires keeping them in shot

and in focus from great distances.

Few people on the planet can do it, and Barrie is one of the best.

But this was the first time he'd attempted to film

the legendary Anna's hummingbird.

On the edge of a university campus in California,

he has his first view of the male's display.

The hummingbird has gone really high in the sky,

and it's coming in. Whoa!

He's so small and he's just moving so quickly.

I think it's going to be a real challenge to film it.

Hummingbird scientist Christopher Clark

knows a trick that might help.

He uses a stand-in female bird to attract the males.

The birds are going at the speed of freeway traffic.

Barrie is able to piggyback on Chris's studies

to give him a chance.

And as backup, the team have brought their own range

of stand-in models.

First up, a slightly moth-eaten stuffed bird.

According to the scientists,

this female, the way her tail is,

means that she's a bit...

she looks a bit more up for it than the others.

The model is so enticing, the male skips courtship altogether.

Onto model number two.

A more modest embroidered female.

Playing hard to get,

she's perfect for encouraging the males to perform

their courtship display.

In fact, they're so keen to show off to her, the crew need to cover

her up while Barrie prepares.

I'm ready.

With the set-up sorted, it's now down to Barrie versus the birds.

Oh, here he is.

-Whoa!

-HE LAUGHS

That's really quick.

You think you're so clever!

Blimey!

I'm not sure this is going to work, I'm just trying.

Things are starting to come together.

That's got to be good, it's got to be good.

Meanwhile, thousands of miles away in the cloud forests of Ecuador,

another team are also challenged with filming a small,

fast-moving animal.

Their mission is to fly alongside wild bats

hunting in complete darkness.

Scientist Nick Dowdy is taking the crew to his study site within

the forest, where he carries out research on how wild bats

hunt tiger moths.

Huge amounts of specialist equipment are required.

And unable to get this deep into the jungle,

the team's first task is to bring the jungle to them.

A studio within the forest will be a temporary new home for the bats.

It'll replicate the jungle

but will also be rigged with kit by cameraman Rob Drewett.

It takes five days to get everything just right before switching

to night shifts, entering the world of the bats.

Challenged with flying his camera alongside them,

Rob has a stabilising pulley system.

And his state-of-the-art infrared camera

is able to slow down the images over 40 times.

Rob's also relying on some rather less technical equipment.

I'm having to go around and just make sure there's no

holes for them to get out of the enclosure.

Fingers crossed we've got it sorted.

I think we have, it looks pretty good.

So even like that, they're going to get out, aren't they?

While Rob double checks, there's also time for final kit tests

before everything is bat-ready.

-You're flapping!

-HE LAUGHS

Nick is trained to safely capture

and release wild bats for use in his studies.

This expertise ensures the welfare of the animals during filming.

It's also an opportunity for Nick to gain insights into their behaviour.

CLICKING

Echolocation clicks from a bat detector show

the occupants are getting to know their new home.

Now filming can finally begin.

Night after night, Rob starts to get the shots he needs.

And the controlled conditions of the forest studio come into their own.

-Oh, here we go.

-Here we go.

-Yes, it's pretty good.

-Yeah.

But Rob's greatest challenge is yet to come - filming the bats hunting.

Back in California, the hummingbird crew have hit a problem.

The star model has lost its appeal

and instead of diving, the males are now attacking.

There's no option but to turn to the real deal,

a female Anna's hummingbird.

For these shy creatures,

Barrie has to rely on more traditional techniques.

We just need everything to kind of line up.

We need the females to come, land on the perch

and the male has to be looking the right way.

It's going to be a test of patience,

filming all day, every day, in a hide in the Californian heat.

The shoot is in its last few days,

and finally, everything is falling into place.

Barrie's able to capture interactions between the male

and a real female, and reveal the world's fastest courtship

display in incredible detail.

That's really nice, really good.

Back in Ecuador, Rob also faces a waiting game.

He's truly immersed in the bat's world,

becoming nocturnal himself

as he strives to capture their hunting behaviour.

There's no way of knowing exactly when the bats will strike.

And once triggered, the camera needs

at least seven seconds to save the shot.

Oh, that was close.

It's frustrating for Rob

if the action happens before the camera re-arms.

And then...

Ah, no. Not now, though.

-..catastrophe.

-No, armed?

Armed.

Ah!

Look at this.

-Ah!

-Oh, my God.

This is disastrous.

I'm a bit nervous about using this camera -

it crashed and we lost a whole night's footage.

So fingers crossed it doesn't do that again.

Having worked through the night for over two whole weeks, Rob's spirits

are low, and he only has a few days left.

But he's not one for quitting.

Am I armed?

Yep.

Oh, that was in frame!

OK, let's have a look at that one.

I think we might have got that. Yes!

Ah, that's nice.

Great, we got one.

-Yes!

-Well done, good work.

After many sleepless nights, Rob's perseverance pays off,

helped by a successful partnership with science, a little

technology and a great performance from the masters of the night sky.

In total, crews have worked over 300 days on location

to film incredible animals in action in the skies.

Life in the air has been captured

in greater detail than ever before.

Seeing how animals survive

and thrive up here has revealed just what it takes to master the skies.