All language subtitles for David.Attenboroughs.Conquest.Of.The.Skies.S01E01.First.To.Fly.2160p.NOW.WEB-DL.DDP5.1.H.265-RAWR_track3_[eng]

The ability to move through the air
in any direction you wish,

to cross continents and oceans,

to range over forests and
deserts and mountains.

All this, birds have been able
to do for 150 million years.

But they weren't the first,
or indeed the last, in the skies.

We are setting out to explore one
of the most astonishing stories

in the natural world.

The way in which animals
managed to rise up

from the surface of the Earth
and colonise the air.

From the dazzling
aerobatics of the insects...

...to the majesty of
ancient winged reptiles.

The splendour and agility
of birds...

...and the sonar-guided precision
of night-flying bats.

Flight has been the key
to the success

of some of our planet's
most remarkable inhabitants.

To analyse their spectacular skills,
we will use the latest technology.

And we will travel around the world,

from the jungles of Borneo,

to the fossil-filled rocks of China,

and the cloud forests of Ecuador.

We will take you into the air...

...and travel with animals
as they fly.

Evidence for the very beginnings
of this astonishing story

can be found close to home
in the fens of Cambridgeshire.

Here live creatures
that have an ancestry

stretching back millions of years.

Nobody knows exactly how the first
flying animals in the world evolved.

But there are creatures alive today

that can take us back to those
far distant, remarkable times.

And they live, surprisingly, underwater.

Looking down through the surface
to the river bed

is like travelling back in time
over 320 million years.

It was then in an age long before
even the dinosaurs evolved

that creatures like this first
appeared in the waters of the earth.

It's an insect.

A ferocious predator with jaws
like a mechanical grab.

It seems unlikely, but
this animal's ancestors

were among the first
creatures ever to fly.

But this one is not yet adult.

It is a larva and it doesn't spend
all its life in the water.

It has another life and
another body above the surface.

Early one morning,
it climbs up a reed.

A split appears in its skin,

and a very different-looking
creature begins to emerge.

It has four lumps on its back
that might, perhaps ancestrally,

have become either gills
or protective armour plates.

But now they develop
into something very different.

Wings.

It has two pairs of them.

Liquid from its body is pumped down
along veins to stretch them tight.

As they dry in the sun, they harden.

The water-living dragon
has become the dragonfly.

And the four-winged apparatus
that it uses to get into the air

is the earliest that we know.

Imprints of such wings
have been found in rocks

that were laid down on the bottom
of ancient lakes and streams.

This specimen is about
150 million years old.

And this wing is double that age

at nearly 300 million years old.

Ancient and modern wings
share a structure

that is strikingly similar.

So, today's dragonflies are,
amazingly, living fossils

that can show us how the very first
flyers overcame the pull of gravity,

and took to the skies.

Their wings are marvels
of natural engineering.

But to see how they lift
a dragonfly into the air,

we need to slow the action down.

In principle,
it looks fairly simple.

Each wing beats down,
pushing on the air below,

so lifting the dragonfly up.

But each beat also creates
another air current

that lifts the dragonfly
in a very different way.

And I can demonstrate it using this
strip of paper to represent a wing.

If I blow across the top of it,
it will rise. Watch.

That is because the faster air
moves, the lower its pressure.

So I created a lower pressure
above the wing

and in consequence
it was sucked upwards.

The problem for a flying animal

is to recreate that difference
in airspeed.

The way the dragonfly does
this is remarkable.

As it moves through the air,

we can see that it twists its wings
at different angles.

On the powerful downbeat,

it holds them at a slight upwards
angle to the air flow.

And this produces an extraordinary
effect above the wing.

It creates a swirl behind
the leading edge,

which spins the air round,

increasing the speed of the air
current over the top of the wing.

And just a tiny increase in speed

generates a significant
upwards force,

lifting up the wing
and the dragonfly.

The dragonfly can then change
the direction of its wing beats

to propel it forwards
as well as upwards.

Remarkably,

a dragonfly can beat each of
its four wings independently.

And that enables it to perform an
astonishing variety of manoeuvres.

It can hover.

It can glide.

It can even fly backwards.

For maximum power, it beats
both pairs together

and can make really sharp turns.

So, the very first dragonflies were
able to extend their territories

far and wide.

And as more insects joined
them in the skies,

the dragonflies had the skills
to be deadly aerial hunters.

The ability to fly brought great
advantages to those early insects.

It enabled them to find food,
to escape from predators,

and particularly important,

to travel to new territories
in search of a mate.

Damselflies, like their close
relations dragonflies,

have remained virtually unchanged
for millions of years.

Mating can be quite complicated
when both partners can fly.

And these were among
the first kind of animals

that had to deal with that problem.

The blue colour of this
one shows that it is a male.

To attract a female,

a male must have something
to offer her - a territory.

He chooses a stretch of water

that is likely to contain plenty
of food for his offspring.

Then he guards this territory
against any rivals...

...until a female flies in
and joins him.

He must now grab her,
before she changes her mind,

in mid-air, if necessary.

He uses claspers at the tip of his
abdomen to grip her behind her neck.

Amazingly,

the pair are able to co-ordinate
the beats of their eight wings.

They may mate in the air,

or choose a secluded perch where
they will be safe from predators.

They then they fly around
the territory,

laying their fertilised eggs.

Flight enabled insects
to invade part of the planet

that until then had been
uninhabited - the air.

And they flourished.

So, 320 million years ago, the skies
thronged with flying insects.

But those early four-winged forms

were destined to produce
a whole range of spectacular,

highly specialised flyers.

The need to lay eggs in water

tied the first dragonflies to
streams and ponds like these.

But then, around 20 million years
after their arrival,

a new kind of flying insect appeared
with no such ties to water.

Proof of their success

can be found almost
wherever you look.

And few places more abundantly
than in Borneo.

The very first flyers had
two pairs of wings.

Now, we are looking
for their successors.

One group of creatures adapted
that original four-wing design

with such success
that they diversified

into the most numerous
and widespread group of animals

on the entire planet.

And you can find some
of the most spectacular examples

down there in the rainforest.

Not all insects are hunters.

Some are strict vegetarians,
like this one.

This is the land-living equivalent
of that underwater monster,

the dragonfly larva.

But this larva, instead of catching
little fish and water fleas,

munches wood pulp.

The trouble is that wood pulp
is not very nutritious

and this creatures has to eat it
for at least a year

before it's this size,
which is full grown.

But then, this larva will turn into
an adult which is equally monstrous.

Emerging from beneath the ground,

where it has lived
and fed as a larva, is a beetle.

One of the biggest in the world...

...the Atlas Beetle.

Males like this one are armed
with long horns,

powerful weapons with which
to compete with rivals for a mate.

It now spends most of its time
above the ground,

barging its way
through the undergrowth

where it feeds on tree sap,
and fallen fruit.

This hefty, powerful creature may
not look as if it could fly...

...but it can.

At key moments in its life,

it takes to the air to look
for new sources of food...

...and, of course, a female.

All this burrowing
and rummaging around

could injure delicate flight wings.

So beetles have hardened
the front pair

to form this pair of
protective covers,

and the delicate flight pair are
stowed away in safety underneath.

To see how the wings are folded away
beneath their covers,

we need to wait for take-off.

As it flaps,
sprung hinges click open

and the wings are stretched
to their full size.

The working wings create lift

in just the same way
that the dragonfly's wings do,

and the front wings,
which have now become covers

are held out to the side, and their
shape does give a little extra lift.

But it's clear that this is
really, rather a clumsy flyer.

Landings can be clumsy too.

And now those fragile wings
must be carefully packed away

beneath their covers.

They are guided by a line
of tiny hairs

at the base of the abdomen.

These grip the wings
and help push them into position.

The beetle does it
with all the care and precision

that a sky diver uses
when packing away his parachute.

Once in a new territory,

it will stake out a fresh
source of food,

and then defend it until
a female arrives.

The beetle way of life proved
astonishingly successful.

There are over 370,000 different
species of beetle so far discovered,

an unbelievable figure.

So, early on, the beetles managed
to fly, as much as they need to,

with just one pair of wings.

And then,
around 57 million years ago,

came another key development
in the history of flight.

A new type of insect appeared
with two pairs of wings

that became, in effect,
huge billboards.

Wings that are, perhaps, the most
dazzlingly beautiful of all...

...butterflies.

To create these extraordinary wings,

the butterflies evolved
a complex life cycle.

They hatch from eggs as little
worms with legs -

caterpillars.

But, unlike many beetle grubs,

caterpillars
find their food above ground,

where they're very vulnerable
to predators.

So they have evolved
several strategies

to accumulate all the body mass
they will need

to become flying adults.

The first is to eat as much as
they can, as quickly as they can.

Many are able to reach full
size in just a matter of weeks.

Of course, a little thin-skinned,
fat-filled sausage

is a tempting morsel for any
bird or reptile.

So caterpillars have to have
ways of defending themselves.

This one, which is the caterpillar
of a lovely swallowtail butterfly,

has disguised itself as a bird
dropping.

And if that doesn't deceive a bird,
and a bird goes for it,

it has another form of defence.

It's emitted a rather
unpleasant smell as well.

Mm.

In the struggle to survive long
enough to become winged adults,

other caterpillars have developed

other equally ingenious
forms of defence.

Concealed within
these fluffy strands

are short, stinging spikes.

And this one is armed
with long spines,

which have really painful stings.

Not only that,
it has these bite-warning colours,

to tell any potential predator

that they'll be in trouble
if they attack.

This caterpillar may appear
to be dangerous,

but it is, in fact, a fraud.

The spines don't sting at all.

It's relying on its disguise to make
a potential predator think twice,

and leave it alone.

Or you can simply hide.

These little tents

have been made by the caterpillars
of a skipper butterfly.

Each caterpillar has started

by making a circular
cut in the edge of the leaf.

But it's left one segment uncut,
so it can act as a hinge.

Then it pulls
over the whole segment,

and hides beneath to munch
away at the tissues of the leaf.

And if I just pull it up...

...there's the caterpillars.

Caterpillars that survive
this hazardous stage

can now build their wings
and turn into adults.

They undergo
a truly radical transformation.

Instead of shedding a final
layer of skin as the dragonfly does,

a caterpillar first surrounds
itself with a protective shell

to act as a sort-of changing room,
within which it dismantles

and then completely
reconstructs its body.

After around ten days, it
emerges as a butterfly.

Now, fluid pumps
along veins in the wings,

to stretch them
out to their full size.

And then it is ready to fly.

Butterflies live on nectar
which they collect from flowers.

Like dragonflies and beetles,
they also fly to find a mate,

but the way their beat
their colourful wings

is significantly different.

This lovely creature has
two pairs of wings,

but it has in effect
turned them into one.

It's done that quite simply by
overlapping the larger front pair

over the smaller hind pair,

so that when the front pair
beat down,

they automatically press
down the lower pair.

The lower pair themselves don't have
the muscles to beat down

but just enough strength
to return up.

A butterfly's overlapping wings,

compared to the size of their
bodies, are enormous,

around ten times the size
of other insect wings.

Because the wing is larger,
each beat can generate

a huge amount of lift.

So, to stay airborne,

a butterfly needs to flap
less often than other insects.

But that slow wing-beat
also enables it

to make rapid and unpredictable
changes of direction.

And that allows butterflies to fly
in that zigzag, erratic way

which makes them so difficult
to catch

if you are a butterfly collector

or, more importantly, a predator.

The combined front and hind wings
of the butterfly

not only constitute a very effective
flying mechanism,

they can also carry messages.

In fact, they carry some of the
loveliest advertisements

in the whole of the animal kingdom.

Like, for example, this beautiful
golden birdwing butterfly

from Borneo.

The butterflies' huge wings
provide a spacious canvas

on which to display fantastically
elaborate designs.

So, how are these flying
advertisements created?

The secret lies in the microscopic
structure of the wing's surface.

These overlapping scales,
lined up like tiles on a roof,

have evolved from bristles
that were once tiny sensors.

Some contain tiny packets of pigment
that give the wings colour.

Others have a complex structure
which splits the light

so that when viewed
from a particular angle,

it reflects a brilliant iridescence.

There are over 18,000 species
of butterfly around the world,

and each has wings
with their own distinctive design.

These ravishing colours
and delectable patterns,

of course, enable a male butterfly
and female a butterfly to know

whether or not they belong
to the same species.

And a mature adult ready to mate
can identify a suitable partner

from surprising distances.

When a male and female
eventually meet,

they flutter around each other
in a ritual dance.

Each is checking out
the flying skills

and wing patterns of the other.

If both pass the test, they mate.

The sheer size of butterfly wings

might seem to condemn their owners
to a slow, almost dawdling flight.

But they can be much more efficient
aeronauts than you might suppose.

Butterflies may not be able
to fly very fast,

but, astonishingly for such
frail-looking creatures,

they can travel for hundreds
of miles in search of food.

New discoveries are revealing that
butterflies make immense journeys.

And one of the most exciting
of these studies

is taking place 7,000 miles west
of Borneo, in Europe.

I am joining a research project
in central Spain

to look for one of the greatest
of all butterfly travellers...

...the painted lady.

Every spring, painted ladies appear
in Spain in great numbers.

But Spain is just a stop-over.

An international team of scientists

are uncovering evidence
of an astonishing journey

right across Europe and beyond.

This hugely ambitious project

is the brainchild of
Dr Constanti Stefanescu.

Detailed records of when
and where painted ladies appear

have revealed an extraordinary
mass migration.

We were able to collate huge
numbers of observations

from more than 60 different countries

and maybe 35,000 records.

Really?

Many people contributing
their observations

and for the first time it was
possible to understand

the general pattern of migration
all year round.

By combining this wealth of data,

the team are revealing a route map
that spans incredible distances.

And it begins in North Africa.

Large numbers of painted ladies
breed in Morocco over the winter,

before setting out across
the Mediterranean to Europe.

They then follow the
spring bloom north,

as the plants that they
and their young feed on

sprout leaves and flowers.

In the summer they appear
in Britain and Scandinavia.

But no individual butterfly
lives long enough

to achieve this huge
journey by itself.

Each step is taken
by a new generation.

So this painted lady in Britain

is the grandchild of a butterfly
that set out from Morocco.

But then, in autumn,
all the painted ladies vanish.

Do they simply die out?

Or could there be a return leg
to their epic migration?

Searching for an answer
to this mystery

has given the project its most
astonishing revelation yet.

And it comes from a part of the team
based at

Rothamsted Research Institute,
just outside London.

The key discovery emerged
from a surprising source - radar.

Our radar has a vertical
pointing beam

and it illuminates a narrow column
of the sky above,

like shining a powerful spotlight
up into the sky.

And we're able to detect
individual insects

as they fly through that beam.

The signal is so detailed it can
even help identify the species.

And during the autumn
disappearance,

the radar picked up large numbers
of painted ladies.

They weren't dying out.

They were on the move. And they were
flying at astonishing heights.

What we found was, in fact, that the
painted ladies were highly abundant

at heights of 300, 400, 500 metres
above the ground.

At this great height they were
invisible to observers down below.

This explained their disappearance.

But the butterflies had their own
very good reasons

to travel at such altitudes.

One of the benefits of flying at
3-400m above the ground is that

the wind speeds are much faster
than they are at ground level.

So the insects are able to get a lot
of assistance from the wind

and travel much faster
than they would

under their own powered flight.

And we see these painted ladies
travelling at 50 or even 70km/h.

As well as measuring the phenomenal
speed of their flight,

the radar also revealed
its direction.

They were heading south.

So, where were they going?

The astonishing answer

came from Constanti's far-flung
network of observers.

And the crucial piece of data
was gathered in Africa.

Some expeditions in Africa in
October, November have shown that

there is a huge arrival of
- butterflies at that moment.
- Really?

So, by the end of the summer,

the newborn butterflies in Europe
start to migrate way back to Africa.

Really?
Yeah!

A final generation riding
on high altitude winds

makes an immense journey of
up to 3,000 miles to West Africa

in just a matter of days.

Observers on the ground
and radar in the air

had found proof
of an amazing migration cycle.

Just in one year
the whole cycle is made

and is the succession
of these six generations

moving about 5,000km...
Really?

...in one direction
and 5,000 in another direction.

This migration is in fact

the longest made by any insect
on the planet so far discovered.

But that raised another question:

how did each generation know which
direction in which to fly?

The Rothamsted scientists once again
set out to find an answer...

...by tracking the behaviour
of painted ladies

much closer to the ground.

This is
our flight-simulator experiment.

What we've done is we've tethered
our butterflies to a very fine rod,

and we've put them
inside these flight simulators.

They are rigged up to the computer,

and the butterflies
are free to turn,

and as they're turning,
we're recording that turning,

and we can actually draw out the
flight path that they would've taken

if they were free-flying.

The barrel blocks the butterfly's
view of the surrounding scenery,

removing any possible distractions.

The only reference point
they have is the sky above.

Remarkably,

the butterflies consistently
choose a common direction.

These are the flight headings,

so each spot is one
individual butterfly

and the overall
direction that they went in.

So you can see that, on average,
my butterflies were flying south.

What we found when we put
the lid on the simulator,

so they couldn't see the sky,
is, as you'll see,

they didn't know
which direction to go in.

They weren't able to maintain
this southwards heading.

Rebecca concluded that
their ability to choose this heading

must depend on the one thing
they can see in the sky above -

the sun.

Actually,
the sun is a really good cue,

it's very predictable
in its movements across the sky.

And butterflies would be flying
in the middle of the day

when it's warm, when the sun is out,

and the sun would
be in the south at that time of day.

So that's a really clear cue
for the butterflies to know

which way is south.

This in-built compass allows
painted ladies at high altitude

to select a wind
that's heading south,

and so hitch a free ride
on the long return journey,

all the way to Africa.

Some insects face
a very different challenge,

not flying long distances,
but flying in the dark.

A light trap can attract
some of the most remarkable

of these nocturnal flyers...

...moths.

Moths probably evolved to fly
at night to avoid predators.

Their eyes are adapted to low light,

but they also use a second,
highly developed sense - smell.

This is a male moon moth.

Moths overlap their two pairs
of wings

in just the same way
as butterflies do.

And this particular moth
is very special.

It has an extremely short life.
It will only live for a week.

It won't even feed.

It's only object is
to find a female,

and it does that with these
remarkable feather-like antennae.

The female emits a particular,
characteristic scent,

and with those antennae,

the male can sense it
from as much as a mile away.

It then takes off and flies upwind

until, eventually,
it finds the source.

Moths, with their combined
front and rear wings,

are also excellent flyers.

Some live longer
and so need to fly to find food.

This sphinx month's
favourite food is nectar.

It can even hover as it drinks.

So, by overlapping
their two pairs of wings,

butterflies and moths have
become very competent flyers.

But there's one group
of flying insects

that has changed
the back pair of wings

into something quite,
quite different.

Something that enables
them to perform

the most extraordinary
aerial gymnastics.

For the final chapter in our story
of flying insects,

I am returning to London.

The urban jungle
and its human inhabitants

provide plenty of shelter and food

for a particularly adaptable
and numerous kind of insect.

Thank you very much.
- Enjoy.
- Thank you.

An inviting meal like this one will,
I am quite sure,

very soon attract a flying diner

that is one of the most remarkable
of all insect aeronauts.

It is, of course, a fly.

This particular kind, a blow fly
occurs all over the world.

And its ancestors have
been buzzing around

for at least 250 million years.

Flies are so common,

we tend to dismiss them
as just irritating pests.

But their flying abilities
are truly remarkable.

Watch what happens if I try
and swat this one with the menu.

Slowing down the action by 40 times,

we can see how astonishingly
agile flies are.

It makes its escape in the time
it takes me to blink my eye.

The ability to twist and turn
at such high speeds,

and so evade enemies, has made flies
the global success that they are.

They are the jet fighters
of the insect world.

And they owe their
manoeuvrability

not to the shape of their wings
nor the power of their muscles,

but to a set of highly
advanced flight sensors.

A fly has its own version of a
fighter pilot's instrument panel.

Providing constant updates on speed,
altitude, and direction of travel.

A fly gathers this flight data
through its eyes

and these are among
the best in the business.

They can process visual information

around ten times as fast
as our own eyes.

But in high-speed manoeuvres,
even a fly's eyes struggle

with one crucial piece
of flight data.

The angle of its body
in the air and the way it changes.

Information that a human
pilot would get

from an instrument based
on a gyroscope.

And that is essential

if you are going to pull off
a stunt like this one.

Fortunately, flies not only
have eyes to guide them.

They also have a second, and even
more remarkable set of sensors,

one that has derived from
that original four-wing design.

A fly only has
a single pair of wings.

The rear pair have been converted
into something else.

A tiny, club-like appendage,
known as a haltere.

This surprisingly
sophisticated organ

alerts the fly to changes in the
position of its body in the air.

As the fly takes off, each haltere

begins to beat up and down and so
fast, it immediately becomes a blur.

But in slow motion,

we can see that it swings back
and forth like a pendulum.

To understand how the
haltere works,

we need to track its
movement in a mid-air roll.

The weighted tip of the haltere
has a kind of moving inertia,

so that it remains on the same
swinging path as the fly banks.

Now the angle between the body
and the haltere changes,

and the base in put under strain.

This triggers sensors
which register the roll.

The fly can then adjust its wing
beat to correct any imbalance,

however extreme.

New studies into a second,

remarkable use of
the haltere's signal

are taking place at
London's Imperial College.

In the Department of
Bio-engineering,

experts are studying blow flies

to see if their natural
flight mechanics

can improve the performance of
man-made flyers like this drone.

Flies are incredibly manoeuvrable,

and if you look at their performance,

one chasing another one,

it's really hardly any other animal

that can match this sort
of aerodynamic performance.

Holger has devised an experiment to
investigate an intriguing connection

between a fly's halteres and its
other key flight sensor, its eyes.

A tiny motor simulates a series
of high-speed, mid-air rolls.

The way the fly then reacts is
recorded on a specialist camera

which can re-play the action
in slow motion.

As you can see if you look closely,

the head of the fly is
maintained level.

The body is rotating and to
maintain a level gaze

they have to counter-rotate the head.

Keeping the eyes level is vital

if they are to gather accurate
flight information.

And the halteres have been
identified as the crucial sensor

that makes this possible.

Visual system alone would
just be too slow.

That's where, actually,
the halteres come in.

The halteres are extremely
fast in terms of their responses

and their immediate signals that are
then sent to the neck motor system

and to the flight motor system,
they are the first, really,

to compensate for any disturbances.

And if that has happened,

the visual system is perfectly well
situated to cope with the rest.

So, flies lost a pair of wings

but gained an extraordinary new
flight sensor

that made them the most advanced
flyers in the insect world.

Flight has enabled the
insects as a whole

to become an astonishing
global success.

There are twice as many
insect species

than there are of all other
animals put together.

Theirs is a remarkable
evolutionary story

that spans over 320 million years.

From the first four-winged creatures
that emerged from the water,

to the armour-plated beetles which
colonised land away from water.

The butterflies with their huge,
colourful wings...

...and the stunningly
skilful, aerobatic flies.

But skill may not be enough.

Sometimes, sheer size counts.

The insects had the skies
to themselves

for around 100 million years.

But then a new group
of animals appeared.

Animals that could build
bigger bodies,

and they were to lift the techniques
of flying to even greater heights.

As our journey
through time continues,

we encounter
the extraordinary pioneers

of a new wave of larger flyers.

Monstrous, winged reptiles.

Strange feathered dinosaurs,

whose ventures into the air
led to the birds.

And a group of mammals

that conquered the pitch black
of the night.

The bats.

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