0:00:04 > 0:00:09The sky is one of the most challenging places to live.
0:00:10 > 0:00:13But all across the world, extraordinary animals do
0:00:13 > 0:00:16something we can only dream of...
0:00:18 > 0:00:21..take to the air.
0:00:24 > 0:00:26Some spend their whole lives up here.
0:00:29 > 0:00:33Others only visit for a moment.
0:00:36 > 0:00:40We'll discover how many incredible animals thrive in the sky...
0:00:43 > 0:00:46..and what clever tricks they use to get airborne.
0:00:48 > 0:00:51With the help of some specially trained animals,
0:00:51 > 0:00:56the latest technology and special effects techniques,
0:00:56 > 0:00:59we'll reveal brand-new discoveries
0:00:59 > 0:01:02that explain how animals take to the skies.
0:01:05 > 0:01:07This is Life In The Air.
0:01:17 > 0:01:20It's one thing to take to the air
0:01:20 > 0:01:22and let gravity do the rest...
0:01:24 > 0:01:26..but to stay airborne,
0:01:26 > 0:01:29to master true flight,
0:01:29 > 0:01:33you need to push the laws of physics right to the very edge...
0:01:35 > 0:01:38..using power, speed,
0:01:38 > 0:01:42agility, endurance
0:01:42 > 0:01:43and acceleration.
0:01:45 > 0:01:49These are the masters of the sky.
0:02:05 > 0:02:08Meet the whooper swan,
0:02:08 > 0:02:12one of the largest and heaviest of all flying creatures.
0:02:15 > 0:02:19Every year, families fly enormous distances,
0:02:19 > 0:02:23migrating between vital feeding and breeding areas.
0:02:26 > 0:02:29But weighing a whopping 14 kilos,
0:02:29 > 0:02:31how are swans able to fly at all...
0:02:33 > 0:02:35..let alone so far?
0:02:37 > 0:02:40To push the limits of what's possible in the air
0:02:40 > 0:02:43they need strength - and lots of it - every day.
0:02:49 > 0:02:52To fuel their huge bodies, swans need to eat
0:02:52 > 0:02:55over a kilogram of vegetation a day.
0:02:55 > 0:02:59They're constantly in search of enough food to survive.
0:02:59 > 0:03:02And that means flying.
0:03:02 > 0:03:05But when you're this size, just taking off
0:03:05 > 0:03:10is nearly impossible and requires some very clever techniques.
0:03:13 > 0:03:15So, how does he do it?
0:03:18 > 0:03:21To get airborne, he's going to need raw power...
0:03:24 > 0:03:27..and apply it in a very precise way.
0:03:57 > 0:03:59First, he must break free of the water,
0:03:59 > 0:04:02but it clings to his body, holding him back.
0:04:08 > 0:04:12His huge webbed feet need to drive him upwards and forwards.
0:04:19 > 0:04:23Now his gigantic metre-long wings can move freely.
0:04:25 > 0:04:28They push air down and back, delivering yet more power
0:04:28 > 0:04:30to accelerate him further.
0:04:36 > 0:04:41Wings and feet work together to give him the speed he needs to take off.
0:04:48 > 0:04:49Once at this speed,
0:04:49 > 0:04:53the air is moving fast enough over his wings to create a huge
0:04:53 > 0:04:56upward force called lift.
0:04:56 > 0:04:58This fights the downward pull of gravity.
0:05:00 > 0:05:02So how is lift created?
0:05:05 > 0:05:08The special shape of his wing, known as an aerofoil,
0:05:08 > 0:05:12causes air to flow differently above and below his wing,
0:05:12 > 0:05:14and this affects its pressure.
0:05:16 > 0:05:20With low pressure above and high pressure below,
0:05:20 > 0:05:22the wing is pushed upwards.
0:05:31 > 0:05:35The faster the swan goes, the more air flows over the wing,
0:05:35 > 0:05:38and that creates more lift.
0:05:38 > 0:05:41He needs to reach 21 kilometres an hour,
0:05:41 > 0:05:46the critical speed where lift cancels out gravity altogether.
0:05:48 > 0:05:52Then it's undercarriage up, and we have takeoff.
0:06:01 > 0:06:05For such a huge bird to take to the sky,
0:06:05 > 0:06:08everything must come together in one explosive moment
0:06:08 > 0:06:11that lasts just a few seconds.
0:06:24 > 0:06:28Once he's really flying, the same air that helped him
0:06:28 > 0:06:30get up here gives him a new challenge.
0:06:33 > 0:06:37As he powers forwards, the air pushes him back,
0:06:37 > 0:06:39a force known as drag,
0:06:39 > 0:06:42slowing him down and reducing the lift in his wings.
0:06:46 > 0:06:49By beating his wings, he creates a constant source of power
0:06:49 > 0:06:51to maintain air speed.
0:06:53 > 0:06:57Without this thrust, he would soon slow to a standstill...
0:06:59 > 0:07:01..and literally drop out of the sky.
0:07:09 > 0:07:11So swans must keep flapping,
0:07:11 > 0:07:15all the way to their new feeding grounds.
0:07:18 > 0:07:21All flying animals have to wrestle the powerful conflicting forces
0:07:21 > 0:07:26of gravity, lift and drag,
0:07:26 > 0:07:29but the faster they go, the thicker the oncoming air feels,
0:07:29 > 0:07:32and drag becomes an ever bigger problem.
0:07:34 > 0:07:38So what if you're one of the fastest animals on the planet,
0:07:38 > 0:07:43and you're moving at more than 320 kilometres an hour?
0:07:55 > 0:07:57The peregrine falcon.
0:08:02 > 0:08:05Its breakneck speed gives it the edge to surprise
0:08:05 > 0:08:08and strike its prey with devastating force.
0:08:16 > 0:08:18It's spring here in California,
0:08:18 > 0:08:21and a pair of peregrines has a new family,
0:08:21 > 0:08:23and with it, a new problem.
0:08:25 > 0:08:29At four weeks old, each ravenous chick eats more than an adult,
0:08:29 > 0:08:33so both parents need to hunt successfully every day.
0:08:35 > 0:08:38Feeding their growing youngsters is a full time job.
0:08:48 > 0:08:50So what is it about peregrines that makes them
0:08:50 > 0:08:54so much faster than almost any other animal on the planet?
0:08:58 > 0:09:00They've got flying at speed perfected,
0:09:00 > 0:09:02down to the tiniest detail.
0:09:05 > 0:09:08See-through eyelids stop their eyes drying out...
0:09:10 > 0:09:12..and specially shaped nostrils
0:09:12 > 0:09:15slow down the air to make breathing possible at high speed.
0:09:18 > 0:09:20When off on a hunt,
0:09:20 > 0:09:23a peregrine uses updrafts from the cliff face to gain height.
0:09:32 > 0:09:35Up here, it can spot potential prey.
0:09:35 > 0:09:38And when it does, it starts a specialist dive,
0:09:38 > 0:09:40known as a stoop.
0:09:44 > 0:09:47A few deep wing strokes help it accelerate
0:09:47 > 0:09:49to 190 kilometres an hour.
0:09:56 > 0:09:59At this speed, oncoming air smashes into every part
0:09:59 > 0:10:02of the peregrine's body, slowing it down.
0:10:04 > 0:10:07By tucking in its wings, the falcon can slip through the air
0:10:07 > 0:10:10that much easier
0:10:10 > 0:10:14so now 240 kilometres an hour becomes possible.
0:10:18 > 0:10:22But the faster you go, the more of a problem drag becomes.
0:10:29 > 0:10:32At top speeds, every bump on a bird's body will disturb the air
0:10:32 > 0:10:34flowing over it,
0:10:34 > 0:10:37and this turbulence slows the peregrine down.
0:10:38 > 0:10:42But that same turbulence makes special feathers pop up over
0:10:42 > 0:10:44the peregrine's back,
0:10:44 > 0:10:46and this pulls the air back into line
0:10:46 > 0:10:48so it flows smoothly over its body again.
0:10:49 > 0:10:55With drag minimised, peregrines can top 320 kilometres an hour.
0:11:01 > 0:11:05At this speed, they can cover the length of a football pitch
0:11:05 > 0:11:06in only a second.
0:11:09 > 0:11:15This sheer, unadulterated speed makes them masters of aerial attack.
0:11:21 > 0:11:25Top-gun skills allow these falcon parents to keep their chicks fed.
0:11:28 > 0:11:30But these same skills also allow them
0:11:30 > 0:11:34to protect the chicks from anything they think might attack the nest.
0:11:38 > 0:11:40They really don't like intruders.
0:11:43 > 0:11:45At the slightest hint of a threat,
0:11:45 > 0:11:49the falcons will scramble and intercept in seconds.
0:12:05 > 0:12:09The falcon may be smaller and less powerful than many of her targets,
0:12:09 > 0:12:13but pure speed gives her the edge to harass
0:12:13 > 0:12:15and then escape before they can react.
0:12:23 > 0:12:26Pelicans are ten times her size,
0:12:26 > 0:12:28and here's a whole squadron of them.
0:12:30 > 0:12:34But size is no match for precision, high-speed flying.
0:12:46 > 0:12:50Each attack aims to disrupt the pelican's own flight.
0:12:51 > 0:12:54Just jerking their head to one side is all it takes to send
0:12:54 > 0:12:56the pelican out of control.
0:13:08 > 0:13:12Meanwhile, her own high-speed, top-gun skills
0:13:12 > 0:13:13keep her out of harm's way.
0:13:23 > 0:13:28Speed helps a peregrine mother own the skies around her nest.
0:13:33 > 0:13:35But what if you're a high-speed hunter
0:13:35 > 0:13:39and you don't have big, wide open airspaces to fly in?
0:13:43 > 0:13:46What if you lived in an English country garden?
0:13:52 > 0:13:56Flying fast, close to the ground,
0:13:56 > 0:13:59and around a veritable assault course of obstacles...
0:14:00 > 0:14:03..there's a skilful hunter that does just this.
0:14:04 > 0:14:09Meet the master of high-speed aerial agility - the sparrow hawk.
0:14:14 > 0:14:15As his name suggests,
0:14:15 > 0:14:18this pocket-sized predator hunts small birds,
0:14:18 > 0:14:21using surprise as his strategy.
0:14:23 > 0:14:24And this is how it works.
0:14:27 > 0:14:32The targets are right in the middle of a garden over 50 metres away,
0:14:32 > 0:14:34with escape routes in all directions.
0:14:37 > 0:14:40He'll need to use as much cover as possible to hide his approach.
0:14:42 > 0:14:45And by knowing every tree and shrub in his territory,
0:14:45 > 0:14:48he can pick the perfect route -
0:14:48 > 0:14:49skimming hedges
0:14:49 > 0:14:53and hurtling through the undergrowth to maximise the element of surprise.
0:14:56 > 0:14:59But there could be 20 pairs of eyes on the lookout.
0:14:59 > 0:15:03And if any of them spot him, they'll sound the alarm.
0:15:07 > 0:15:11Nine out of ten sparrow hawk hunts fail because of this,
0:15:11 > 0:15:15so he's got to be fast and agile,
0:15:15 > 0:15:18and strike in just four seconds.
0:15:26 > 0:15:28Few flying creatures can do this.
0:15:30 > 0:15:34But then few have the sparrow hawk's supreme flying abilities.
0:15:36 > 0:15:39He has explosive acceleration.
0:15:41 > 0:15:43Long legs fire him out of the blocks.
0:15:48 > 0:15:51Short, rounded wings powerfully scoop up the air, driving
0:15:51 > 0:15:54his lightweight body forwards
0:15:54 > 0:15:57to hit attack speed in under two seconds.
0:16:03 > 0:16:07Now at speed, he keeps a low profile, hugging the ground.
0:16:09 > 0:16:13This low position gives him an extra advantage.
0:16:13 > 0:16:17The air is squeezed between his wings and the ground,
0:16:17 > 0:16:21giving him a high pressure air cushion to ride on.
0:16:21 > 0:16:24This keeps him airborne and saves valuable energy.
0:16:29 > 0:16:32But hurtling along at 50 kilometres an hour gives him
0:16:32 > 0:16:35just hundredths of a second to avoid a collision.
0:16:40 > 0:16:44Short wings are pulled in to pass through the tiniest gaps.
0:16:52 > 0:16:57A long tail does the steering, constantly making fine adjustments.
0:16:59 > 0:17:01And when he needs to turn sharply,
0:17:01 > 0:17:04he slams on the brakes by fanning it out.
0:17:17 > 0:17:20As he gets closer, precision flying becomes critical.
0:17:24 > 0:17:27He needs to stay hidden until the very last moment.
0:17:29 > 0:17:33The last thing a garden bird might see...is this.
0:17:51 > 0:17:53It's all over in seconds.
0:18:00 > 0:18:04The sparrow hawk masters the skies with speed and agility,
0:18:04 > 0:18:07but what if you have neither speed nor agility?
0:18:10 > 0:18:14There's a creature that's so slow and clumsy
0:18:14 > 0:18:16many would doubt it could fly at all.
0:18:16 > 0:18:20And yet, it performs the seemingly impossible.
0:18:27 > 0:18:31The Japanese rhinoceros beetle is covered in protective armour.
0:18:35 > 0:18:38In the world of beetles, he's a colossus,
0:18:38 > 0:18:41weighing a hefty 10g.
0:18:46 > 0:18:51He's on a mission to find a mate, and she could be miles away.
0:18:53 > 0:18:57He doesn't have long, and it's too far to walk.
0:18:57 > 0:18:59So he has to fly.
0:19:01 > 0:19:05But attempting to fly whilst carrying all that heavy body armour,
0:19:05 > 0:19:09he's going to need a combination of power and some extreme moves.
0:19:34 > 0:19:38So how does such a huge beetle stay airborne?
0:19:40 > 0:19:42He has a special flight technique,
0:19:42 > 0:19:45very different to that of most birds.
0:19:48 > 0:19:52Slowed down, you can see that he twists his wing at the base.
0:19:57 > 0:20:00We need a special flight laboratory to see how this helps.
0:20:03 > 0:20:07Now we can see just how the air moves around the beetle's wing.
0:20:10 > 0:20:13Those mini tornadoes spinning off the wing show where
0:20:13 > 0:20:16the beetle is pushing the air back, thrusting him forwards.
0:20:20 > 0:20:25And because it's being pushed down, we know he's also producing lift.
0:20:28 > 0:20:31So far, that's much like a bird.
0:20:36 > 0:20:39But critically, by twisting his wings at the base,
0:20:39 > 0:20:43he can also push air backwards as they move back up.
0:20:46 > 0:20:48And there's the proof.
0:20:49 > 0:20:54This gives him thrust on both the down stroke and the upstroke,
0:20:54 > 0:20:57and that's something that most birds can't do.
0:20:59 > 0:21:01But he doesn't leave it there.
0:21:01 > 0:21:06Even his armoured wing cases are working in his favour,
0:21:06 > 0:21:08forcing air down to create even more lift.
0:21:10 > 0:21:13So he effectively has an extra pair of wings.
0:21:23 > 0:21:26This magnificent beetle is a flying marvel.
0:21:28 > 0:21:30His clever wings give him the extra lift
0:21:30 > 0:21:34and thrust that he needs to cruise at nearly 15 kilometres an hour.
0:21:35 > 0:21:37He's hardly a boy racer,
0:21:37 > 0:21:40nor is a he a long-distance flyer,
0:21:40 > 0:21:43but he can cover half a kilometre in a night.
0:21:43 > 0:21:47And in a jungle, that's enough to find a female.
0:21:48 > 0:21:52This huge beetle's flying mission may have seemed impossible,
0:21:52 > 0:21:53but it's worth the effort.
0:21:55 > 0:21:57Special wings that rotate at the base
0:21:57 > 0:22:01allow the beetle to get more from the air around him,
0:22:01 > 0:22:04keeping him airborne, albeit, rather clumsily.
0:22:08 > 0:22:12But in Central America, there are other creatures who have
0:22:12 > 0:22:14taken this to the next level
0:22:14 > 0:22:18using this technique to fly in almost any direction
0:22:18 > 0:22:20with ultimate precision.
0:22:25 > 0:22:29They're not insects but tiny birds.
0:22:33 > 0:22:37Hummingbirds, each the size of your little finger.
0:22:43 > 0:22:46To the human eye, their flight is no more than a blur.
0:22:55 > 0:22:59It's only when slowed down 50 times you can appreciate
0:22:59 > 0:23:01their incredible control.
0:23:16 > 0:23:19So, why are hummingbirds so special?
0:23:24 > 0:23:28This is one of the world's most spectacular flyers,
0:23:28 > 0:23:31a booted racket-tail hummingbird.
0:23:32 > 0:23:35On the face of it, he's got it made.
0:23:35 > 0:23:38Here in Ecuador, his forest home is full of flowers,
0:23:38 > 0:23:41each with sugar-rich nectar hidden inside.
0:23:45 > 0:23:47But he has a problem.
0:23:47 > 0:23:50These flowers don't provide perches,
0:23:50 > 0:23:53neither do they make nectar easy to get at.
0:24:04 > 0:24:08Now the hummingbird's extraordinary flight technique starts to
0:24:08 > 0:24:09makes sense.
0:24:11 > 0:24:15It hovers so it can move its needle-like beak into position
0:24:15 > 0:24:17with surgical precision.
0:24:19 > 0:24:21Running down the inside of the beak,
0:24:21 > 0:24:25a forked tongue laps up the nectar at up to 13 times a second.
0:24:27 > 0:24:31But just performing a simple hover breaks all the rules
0:24:31 > 0:24:34of traditional flight, so how does he do it?
0:24:37 > 0:24:39It's a technique similar to the beetle's,
0:24:39 > 0:24:41but impossible for other birds,
0:24:41 > 0:24:44and requires a very special pair of wings.
0:24:48 > 0:24:52They're short and stiff to cope with the stress of beating
0:24:52 > 0:24:53at up to 80 times a second.
0:24:59 > 0:25:02But it's how a hummingbird beats its wings that allows it to hover.
0:25:07 > 0:25:11On close inspection, the wing tips move in a figure of eight.
0:25:16 > 0:25:19A unique wrist joint means the wing can rotate through up
0:25:19 > 0:25:20to 140 degrees...
0:25:22 > 0:25:25..so he can thrust air down and back
0:25:25 > 0:25:28not only on the down stroke but also on the upstroke.
0:25:30 > 0:25:31That gets him hovering.
0:25:36 > 0:25:40By having constant power, he can also make tiny adjustments
0:25:40 > 0:25:43throughout the wing beat, and this gives him more control.
0:25:51 > 0:25:54Added precision comes from the way he rolls his body,
0:25:54 > 0:25:56instantly changing the angle he's pushing at.
0:25:58 > 0:26:03With incredible wings like these, he can fly forwards, left,
0:26:03 > 0:26:06right, even backwards.
0:26:08 > 0:26:12This gives him the power and control he needs to get at the nectar
0:26:12 > 0:26:13and move between the flowers.
0:26:15 > 0:26:19But this super powered flying ability comes at a huge cost.
0:26:23 > 0:26:26A thermal camera shows just how much heat is given off when hovering.
0:26:28 > 0:26:31This heat is just a fraction of the energy that a hummingbird
0:26:31 > 0:26:32needs to stay airborne.
0:26:34 > 0:26:38Hovering burns far more calories than any other form of flight.
0:26:39 > 0:26:42To provide his muscles with enough oxygen,
0:26:42 > 0:26:45his heart has to beat at 20 times a second,
0:26:45 > 0:26:48and he needs to drink his body weight in sugary nectar every day.
0:26:54 > 0:26:59In fact, this tiny little bird has the highest metabolism
0:26:59 > 0:27:00of any warm-blooded animal.
0:27:10 > 0:27:13So our hummingbird might have the ultimate control in the air,
0:27:13 > 0:27:17but he'll always be a slave to his uniquely manic lifestyle.
0:27:19 > 0:27:22Trapped in a world where he needs to hover to feed
0:27:22 > 0:27:24and needs to feed to hover.
0:27:33 > 0:27:36Hummingbirds can afford a high-energy lifestyle
0:27:36 > 0:27:38because food is always close by.
0:27:42 > 0:27:45But what if your next meal is hundreds of kilometres away
0:27:45 > 0:27:47and you have to go searching for it?
0:27:51 > 0:27:54You're going to need a completely different flight technique.
0:27:55 > 0:27:59Patrolling the ocean around South Island, New Zealand,
0:27:59 > 0:28:02this is a royal albatross.
0:28:05 > 0:28:08Albatrosses spend the vast majority of their lives out at sea.
0:28:09 > 0:28:12The one time they need land is to nest.
0:28:22 > 0:28:27This albatross is providing for one of the world's biggest chicks.
0:28:33 > 0:28:36At two months old, her chick will eat half a kilo of fish
0:28:36 > 0:28:39and squid in a single sitting,
0:28:39 > 0:28:42so she'll have to travel far and push the limits of flying.
0:28:44 > 0:28:47She's chosen to nest on this wind-blasted cliff
0:28:47 > 0:28:49for a very good reason.
0:28:49 > 0:28:53To take off, she spreads her three-metre wings,
0:28:53 > 0:28:55and the cliff top wind provides the lift.
0:28:58 > 0:29:02Ungainly on land, she is now in her element.
0:29:20 > 0:29:24Out here, fish and squid can be extremely difficult to come by.
0:29:26 > 0:29:29So a mother albatross will scour the ocean
0:29:29 > 0:29:31for up to 1,000 kilometres a day.
0:29:35 > 0:29:37During her lifetime,
0:29:37 > 0:29:41she'll travel nearly two and a half million kilometres.
0:29:41 > 0:29:44That's to the moon and back three times.
0:29:46 > 0:29:50And remarkably, she can do this with barely a wing beat.
0:29:52 > 0:29:55She's one of the world's most efficient fliers,
0:29:55 > 0:29:58using the energy of the air just above the ocean
0:29:58 > 0:30:00to save her own energy.
0:30:00 > 0:30:03She's riding the air like a rollercoaster,
0:30:03 > 0:30:05in a super efficient way.
0:30:07 > 0:30:10But snaking from side to side like this
0:30:10 > 0:30:12seems to make no sense at all
0:30:12 > 0:30:17until you understand how air behaves above water.
0:30:21 > 0:30:24At the water surface, the air collides with the rough waves,
0:30:24 > 0:30:27slowing it down to a virtual standstill.
0:30:29 > 0:30:33But ten metres above the waves, the air flows that much faster.
0:30:38 > 0:30:42It's this difference in air speed that allows the clever albatross
0:30:42 > 0:30:43to fly for free.
0:30:51 > 0:30:55By sweeping up and down, she can use both the fast air
0:30:55 > 0:30:57ten metres above the waves
0:30:57 > 0:30:59and the still air at the water's surface.
0:31:02 > 0:31:05And here's where the sheer efficiency of those long,
0:31:05 > 0:31:07narrow wings is so important.
0:31:09 > 0:31:12As she climbs into the faster wind,
0:31:12 > 0:31:15she can create more and more free lift.
0:31:16 > 0:31:20Then with height on her side, she turns sharply,
0:31:20 > 0:31:24and a combination of gravity and wind now slingshots her downwards
0:31:24 > 0:31:27up to 120 kilometres an hour.
0:31:34 > 0:31:37Known as dynamic soaring,
0:31:37 > 0:31:40the ability to use changes in air speed like this
0:31:40 > 0:31:44means that albatrosses rarely need to flap their wings.
0:31:51 > 0:31:54This energy-saving technique allows them to travel
0:31:54 > 0:31:58huge distances to find food in the open ocean.
0:31:59 > 0:32:00And when you're a mother,
0:32:00 > 0:32:04scraps from a fishing boat are too good an opportunity to miss.
0:32:15 > 0:32:20Now full of food, an albatross's next challenge is to get home again.
0:32:23 > 0:32:26But unlike before, when she could wander in any direction,
0:32:26 > 0:32:30she must now fly directly back to her chick,
0:32:30 > 0:32:33even if that means heading straight into the wind.
0:32:36 > 0:32:39Once again, she reads the air in front of her
0:32:39 > 0:32:41and uses its movement to her advantage.
0:32:45 > 0:32:49Albatrosses use a special organ hidden inside their nostrils
0:32:49 > 0:32:52to constantly measure tiny changes in air speed.
0:32:55 > 0:32:58This guides her to pockets of still air behind each wave.
0:33:00 > 0:33:03Flying is much easier here.
0:33:09 > 0:33:11And when she needs extra lift,
0:33:11 > 0:33:16she can even seek out upwards moving air that flows over each wave crest.
0:33:23 > 0:33:27This way, she can fly all the way home really efficiently,
0:33:27 > 0:33:28even against the wind.
0:33:39 > 0:33:42The chick gets fed because its mother can read the air
0:33:42 > 0:33:44and ride it effortlessly.
0:33:46 > 0:33:49In six months, it will be doing the same.
0:33:54 > 0:33:58The albatross's ability to fly far in search of food allows it
0:33:58 > 0:34:01to exploit the patchy resources of the Southern Ocean.
0:34:03 > 0:34:04But they aren't the only creatures
0:34:04 > 0:34:08that survive by travelling huge distances.
0:34:08 > 0:34:10Others move with the seasons,
0:34:10 > 0:34:13flying between winter and summer homes,
0:34:13 > 0:34:16in the biggest journey of their lives.
0:34:18 > 0:34:19Migration.
0:34:22 > 0:34:24Over thousands of kilometres,
0:34:24 > 0:34:28across countries, sometimes even entire continents.
0:34:32 > 0:34:38Insects, bats and birds all make these journeys to find food,
0:34:38 > 0:34:39and breed as the seasons change.
0:34:45 > 0:34:48These are some of the toughest physical challenges
0:34:48 > 0:34:50any animal undertakes.
0:34:53 > 0:34:57Many die en route, and exhaustion is the biggest killer.
0:34:59 > 0:35:04So any way that you can save energy might save your life.
0:35:10 > 0:35:14There's one animal that that flies with incredible efficiency,
0:35:14 > 0:35:17not on its own but as a team.
0:35:19 > 0:35:24European cranes migrate nearly 3,000 kilometres every year
0:35:24 > 0:35:26between their wintering grounds in Spain
0:35:26 > 0:35:28and their summer home in Scandinavia.
0:35:32 > 0:35:34These cranes travel together as a family,
0:35:34 > 0:35:38with the chicks learning from their parents.
0:35:38 > 0:35:40It's how they fly as a group that's going to give them
0:35:40 > 0:35:44all a crucial advantage on their long and arduous journey.
0:35:48 > 0:35:50Adult pairs mate for life,
0:35:50 > 0:35:53and they dance together every year to strengthen family bonds.
0:35:58 > 0:36:01THEY WARBLE
0:36:15 > 0:36:17This is no frivolity.
0:36:17 > 0:36:20How they bond and work together might make the difference
0:36:20 > 0:36:24between life and death, particularly for the youngsters.
0:36:29 > 0:36:31To understand how teamwork helps them,
0:36:31 > 0:36:34we need to see the world from a crane's perspective.
0:36:40 > 0:36:44Cranes are relatively large and heavy birds,
0:36:44 > 0:36:47yet they'll fly multiple marathons in just one day.
0:36:49 > 0:36:51This burns a lot of energy.
0:36:52 > 0:36:56Like albatrosses, they're going to have to fly efficiently
0:36:56 > 0:36:59if they're going to make the distance.
0:36:59 > 0:37:01But unlike albatrosses,
0:37:01 > 0:37:05cranes can't rely on saving energy by soaring all the time.
0:37:10 > 0:37:12To make this journey,
0:37:12 > 0:37:15they will need to flap their wings hard...
0:37:17 > 0:37:21..so they make every flap count by working together,
0:37:21 > 0:37:24and that means formation flying.
0:37:31 > 0:37:34All crane species will fly in the same ingenious way.
0:37:41 > 0:37:42Each flock member flies
0:37:42 > 0:37:46slightly behind and slightly to the side of the bird in front,
0:37:46 > 0:37:48creating a characteristic V shape.
0:37:53 > 0:37:55But each bird must be positioned exactly
0:37:55 > 0:37:57if the teamwork is going to pay off.
0:37:58 > 0:38:02To understand why, we need to see how the air moves
0:38:02 > 0:38:04around a crane wing in flight.
0:38:08 > 0:38:12Each bird leaves a wake in the air behind it.
0:38:12 > 0:38:15A tube of spiralling air trailing behind the wing tip
0:38:15 > 0:38:18still contains energy from the bird's last flap.
0:38:20 > 0:38:23If the bird behind gets in the right position,
0:38:23 > 0:38:27it can use the upward motion of the spiral to keep itself up,
0:38:27 > 0:38:29and therefore save its own energy.
0:38:32 > 0:38:35So one flap can be used by more than one bird,
0:38:35 > 0:38:38they're literally sharing the load.
0:38:46 > 0:38:49Formation flying could save each bird in the team
0:38:49 > 0:38:52over 10% of its energy.
0:38:52 > 0:38:55On a long migration, this could make the difference
0:38:55 > 0:38:57between success and failure.
0:39:05 > 0:39:09The leader of the V formation has to work the hardest,
0:39:09 > 0:39:12with no energy to inherit from the birds in front of it,
0:39:12 > 0:39:15so the cranes take it in turn to lead
0:39:15 > 0:39:18and share the work around the team.
0:39:21 > 0:39:24They also share their knowledge.
0:39:24 > 0:39:27Youngsters learn the migration route from their parents,
0:39:27 > 0:39:31so eventually they'll be able to lead a family of their own.
0:39:34 > 0:39:38Cranes may not be the strongest or the fastest flyers,
0:39:38 > 0:39:39but their technique as a team
0:39:39 > 0:39:42gets them to their breeding grounds each year.
0:39:49 > 0:39:52Formation flying is used by many birds,
0:39:52 > 0:39:55it's an energy-saving trick that makes long distances
0:39:55 > 0:39:56that little bit easier.
0:40:04 > 0:40:08Many flying creatures have one particular flying skill that
0:40:08 > 0:40:09gives them an edge.
0:40:09 > 0:40:14But perfecting one skill means you might not be so good at others.
0:40:17 > 0:40:21When you're built for speed, it's difficult to be an acrobat.
0:40:24 > 0:40:27Amazing acceleration burns energy,
0:40:27 > 0:40:30but that's no good if you're a long distance flyer.
0:40:37 > 0:40:41And if you need to power a large body into the air,
0:40:41 > 0:40:44being manoeuvrable becomes more of a challenge.
0:40:53 > 0:40:56It can work to be a specialist,
0:40:56 > 0:40:58but what if you need to be good at everything?
0:40:59 > 0:41:03What if you need to combine many different flying skills
0:41:03 > 0:41:05into the ultimate flying machine?
0:41:06 > 0:41:09There are some creatures who've done just that.
0:41:09 > 0:41:14They aren't birds, they aren't bugs - they're mammals.
0:41:20 > 0:41:22Dawn in Texas,
0:41:22 > 0:41:25and half a million Brazilian free-tailed bats
0:41:25 > 0:41:27are returning home after a night out feeding.
0:41:29 > 0:41:31During the next few seconds,
0:41:31 > 0:41:34their flight skills will be pushed to the limits.
0:41:35 > 0:41:39For these aerial masters, the last part of their journey is
0:41:39 > 0:41:41the most dangerous.
0:41:41 > 0:41:43Predatory hawks are waiting.
0:41:53 > 0:41:56The bats are heading to the safety of a cave.
0:41:56 > 0:42:00Their challenge is to completely change the way they fly
0:42:00 > 0:42:01more than once.
0:42:09 > 0:42:12First fly fast,
0:42:12 > 0:42:14topping a 100 kilometres an hour.
0:42:16 > 0:42:20Next, hit the brakes as they fly into the pitch dark.
0:42:23 > 0:42:28Finally, fly alongside the half a million other bats in the dark cave.
0:42:31 > 0:42:35Now it's about being manoeuvrable and trying to avoid collision.
0:42:40 > 0:42:43Within a few seconds, the bats have to perform a range of completely
0:42:43 > 0:42:47different flight techniques, each of them highly specialised.
0:42:50 > 0:42:55This requires incredibly versatile responsive wings.
0:42:57 > 0:43:01Bats do something unique in the natural world.
0:43:01 > 0:43:05They fly not with their arms but with their hands.
0:43:07 > 0:43:10A bat's wing is a miracle of flight engineering,
0:43:10 > 0:43:15complete with thumb and four fingers and self tensioning skin in-between.
0:43:16 > 0:43:19Its shape can shift in all three dimensions
0:43:19 > 0:43:22and far more than any bird or insect.
0:43:25 > 0:43:27No other wing gives this level of control.
0:43:31 > 0:43:35Innovative wing design allows the bats to cover huge distances
0:43:35 > 0:43:37to feed,
0:43:37 > 0:43:39fly fast to evade predators
0:43:39 > 0:43:42and manoeuvre tightly in their crowded cave.
0:43:52 > 0:43:56This expert flying ability allows the bats to use the caves
0:43:56 > 0:43:58as giant underground nurseries.
0:44:00 > 0:44:04Hundreds of thousands of baby bats huddle together for warmth.
0:44:06 > 0:44:11In here, all bats are as safe as they're ever going to be.
0:44:11 > 0:44:15But for the adults, that's about to change.
0:44:20 > 0:44:25Outside, dusk is fast approaching, so soon the adult bats
0:44:25 > 0:44:28must leave the cave again to feed for the night.
0:44:30 > 0:44:32But the hawks are waiting.
0:44:33 > 0:44:35The hawks can't see in the dark,
0:44:35 > 0:44:40so every second the bats stay underground gives them an advantage.
0:44:47 > 0:44:50But sooner or later, each bat is going to have to
0:44:50 > 0:44:53push its flying skills to the limit once more.
0:45:00 > 0:45:05Their strategy is to emerge together giving safety in numbers -
0:45:05 > 0:45:08an incredible feat of synchronised flying.
0:45:09 > 0:45:12More bats swirl up from deep underground
0:45:12 > 0:45:15until the cave entrance is full to bursting point.
0:45:26 > 0:45:29With their wings now outstretched, they can build up speed.
0:45:35 > 0:45:38Tens of thousands of bats,
0:45:38 > 0:45:41all waiting until the last possible moment.
0:45:53 > 0:45:55With deep powerful wing beats,
0:45:55 > 0:45:58the bats can accelerate through the danger zone.
0:46:03 > 0:46:06The hawks are overwhelmed by their sheer numbers,
0:46:06 > 0:46:09their manoeuvrability and their speed.
0:46:18 > 0:46:20Now safely away from the cave,
0:46:20 > 0:46:23they're free to fly as far as they need
0:46:23 > 0:46:26to their night-time feeding grounds.
0:46:35 > 0:46:38A radical innovation in wing design,
0:46:38 > 0:46:40flying with their hands
0:46:40 > 0:46:45has made bats perhaps the most versatile of all flying animals.
0:46:47 > 0:46:51They're the only mammal to have truly mastered life in the air.
0:46:55 > 0:46:59For all flying creatures, staying airborne is a constant challenge.
0:47:01 > 0:47:05A life in the air requires special skills and remarkable techniques.
0:47:08 > 0:47:10But if you can survive up here,
0:47:10 > 0:47:13there are huge opportunities to be had,
0:47:13 > 0:47:18so every animal has its own strategy to give it an edge...
0:47:19 > 0:47:22..as it masters the sky.
0:47:39 > 0:47:42In Life In The Air, the team's mission was to reveal the incredible
0:47:42 > 0:47:46abilities of airborne animals in more detail than ever before.
0:47:47 > 0:47:52Weeks of patient filming allowed the team to capture real-life events,
0:47:52 > 0:47:55like peregrine falcons attacking their animal neighbours.
0:47:58 > 0:48:01But to reveal the science behind how these animals master the skies
0:48:01 > 0:48:03required additional filming tricks
0:48:03 > 0:48:07and some incredible individuals who would allow the team to capture
0:48:07 > 0:48:08their unique behaviour...
0:48:10 > 0:48:13..impossible to achieve in any other way.
0:48:16 > 0:48:18To film the planet's most accomplished flyers,
0:48:18 > 0:48:20the team needed to become part of their flock.
0:48:22 > 0:48:26Key to their success was a unique relationship between the animals
0:48:26 > 0:48:28and the people that work with them.
0:48:30 > 0:48:32The more ambitious the shoot,
0:48:32 > 0:48:35the more important this relationship becomes,
0:48:35 > 0:48:37and none presented a bigger filming challenge
0:48:37 > 0:48:41than keeping up with four tame whooper swans in Scotland
0:48:41 > 0:48:44and flying alongside a family of European cranes
0:48:44 > 0:48:46high above the French countryside.
0:48:50 > 0:48:54First meet Olive, Earther, Yellow and White,
0:48:54 > 0:48:56and their human mum, Rose Buck.
0:48:56 > 0:48:58If their mum's here...
0:48:58 > 0:49:02When the swans first hatched nine years ago, the first thing
0:49:02 > 0:49:05they saw was Rose, so to them, she's the leader of the flock.
0:49:08 > 0:49:11Rose and her husband, Lloyd, have a close bond
0:49:11 > 0:49:14with over 20 different bird species...
0:49:14 > 0:49:15Oh, yes.
0:49:15 > 0:49:18..all film stars in their own right.
0:49:19 > 0:49:22And whilst the swans are on centre stage this time,
0:49:22 > 0:49:25the whole family comes along for the ride,
0:49:25 > 0:49:27including a golden eagle called Tilly.
0:49:27 > 0:49:30Basically, when we go away, they all have to go with us
0:49:30 > 0:49:32because they're like our extended family,
0:49:32 > 0:49:34and that's when they're at their happiest.
0:49:34 > 0:49:36You wouldn't leave your children behind if you went away,
0:49:36 > 0:49:39so they expect to come with us.
0:49:39 > 0:49:43The Buck family are heading to Loch Lomond in Scotland,
0:49:43 > 0:49:46where the plan is to film alongside the swans in their natural habitat,
0:49:46 > 0:49:49capturing their flight in minute detail.
0:49:53 > 0:49:55At the heart of this immense technical challenge is
0:49:55 > 0:49:58a state-of-the-art stabilising system,
0:49:58 > 0:50:00to smooth out any bumps in the water...
0:50:01 > 0:50:06..and a high-speed powerboat that can top 65 kilometres an hour.
0:50:11 > 0:50:14After some final words of encouragement from Rose,
0:50:14 > 0:50:16it's time to put the plan into action.
0:50:20 > 0:50:21Let's go, go, go!
0:50:27 > 0:50:28With Rose at the bow,
0:50:28 > 0:50:31the swans are totally unfazed by the speeding boat,
0:50:31 > 0:50:34which is more than can be said for the director.
0:50:34 > 0:50:37It's a really difficult thing to do when
0:50:37 > 0:50:39something as amazing as this
0:50:39 > 0:50:41to be thinking about your job and the shots,
0:50:41 > 0:50:44cos it's utterly awe-inspiring.
0:50:44 > 0:50:47Without an image stabiliser, it's virtually impossible to get
0:50:47 > 0:50:48a steady shot at speed.
0:50:49 > 0:50:53Cameraman Rob Drewett has the advantage of the stabiliser,
0:50:53 > 0:50:56but wind gusts are causing him unexpected problems.
0:51:00 > 0:51:02- Uh... It's gone.- What's happened?
0:51:04 > 0:51:06As the boat hits 65 kilometres an hour,
0:51:06 > 0:51:09the stabiliser really starts to struggle.
0:51:11 > 0:51:13As soon as I took it away from my body,
0:51:13 > 0:51:16you...you felt the wind take it.
0:51:16 > 0:51:19The elements aren't beating the stars,
0:51:19 > 0:51:21but they're causing big problems for the technology.
0:51:21 > 0:51:23Ah, it just died.
0:51:23 > 0:51:25- We've got a bit of a problem.- Yeah.
0:51:30 > 0:51:32When you're pushing the limits of filming technology,
0:51:32 > 0:51:36sometimes you really need to think on your feet.
0:51:36 > 0:51:40We're now having to go to new extremes to try and get
0:51:40 > 0:51:42our equipment working well,
0:51:42 > 0:51:44and we...we're going to use a dustbin!
0:51:44 > 0:51:48With a rather unorthodox wind guard taking shape,
0:51:48 > 0:51:50there's nothing the Buck family can do,
0:51:50 > 0:51:52except indulge in some family time.
0:51:55 > 0:51:57You wouldn't want to be skinny dipping!
0:51:57 > 0:51:59Gor, struth, you wouldn't.
0:52:02 > 0:52:05Meanwhile, the camera crew work on into the night.
0:52:10 > 0:52:13It's the last day in Scotland, and the crew have their hopes
0:52:13 > 0:52:17pinned on a £15 bin shielding a £50,000 camera system.
0:52:19 > 0:52:20This is the 11th hour,
0:52:20 > 0:52:26it always seems to boil down to the last day, but that's all we've got.
0:52:26 > 0:52:30Now everything needs to come together in one perfect run.
0:52:43 > 0:52:45Lovely.
0:52:45 > 0:52:48So it looks like the shroud is doing the job, which is
0:52:48 > 0:52:52brilliant cos it took us two hours last night to turn
0:52:52 > 0:52:55a dustbin into something that can make us film swans.
0:52:55 > 0:52:57Look at this! Oh, wow!
0:53:01 > 0:53:05Filming flying animals at speed has proved difficult enough on water...
0:53:07 > 0:53:10..but it's that much harder when you take to the air
0:53:10 > 0:53:14with a flock of European cranes half a mile above the Earth.
0:53:19 > 0:53:23To get a true bird's-eye view, you need a microlight,
0:53:23 > 0:53:26a pilot with a family of friendly cranes
0:53:26 > 0:53:28and a cameraman with a head for heights.
0:53:30 > 0:53:32Like Rose is mother to her swans,
0:53:32 > 0:53:36Frenchman Christian Moullec knows each of his family by name.
0:53:36 > 0:53:40- Is this Dennis? - No, no, no. Dennis, no.
0:53:40 > 0:53:41THEY LAUGH
0:53:41 > 0:53:44Christian has been working with these particular birds
0:53:44 > 0:53:47for two years, so when the microlight engine roars...
0:53:49 > 0:53:50..they know it's time to fly.
0:53:59 > 0:54:02The cranes follow the microlight in formation,
0:54:02 > 0:54:04using the updraft from its wing to save energy.
0:54:08 > 0:54:10They're performing perfectly,
0:54:10 > 0:54:15just in completely the wrong place for cameraman Richard Cook.
0:54:15 > 0:54:18Getting them away from the wing and into the right spot requires
0:54:18 > 0:54:22precision teamwork, and this is extremely difficult.
0:54:34 > 0:54:36The birds move around so much, so quickly,
0:54:36 > 0:54:39and then just trying to guess where they're going to be.
0:54:39 > 0:54:41So they drop off the wing here and they come down
0:54:41 > 0:54:43and then underneath the aircraft, up the other side.
0:54:43 > 0:54:46It's very frustrating, but we will get there.
0:54:49 > 0:54:52- Christian.- Yes? - Your birds are terrible!
0:54:52 > 0:54:54No, you are a terrible cameraman.
0:54:54 > 0:54:56RICHARD LAUGHS
0:54:56 > 0:55:00With something this complicated, there's no substitute for practise.
0:55:02 > 0:55:04But the longer you're in the air,
0:55:04 > 0:55:07the more chance something very serious will go wrong.
0:55:11 > 0:55:14The engine has cut out, and with no power,
0:55:14 > 0:55:17Christian and Richard have to make an emergency landing.
0:55:24 > 0:55:27It's at times like this that 25 years of experience comes
0:55:27 > 0:55:29sharply into play.
0:55:34 > 0:55:37On the final approach, they are fully committed.
0:55:44 > 0:55:46Thankfully, it's a perfect touchdown.
0:55:50 > 0:55:53And the cranes don't seem to know what all the fuss is about.
0:55:53 > 0:55:57We landed safely, just glided in, but there's not a lot we can do.
0:55:57 > 0:55:59As you can see, this is absolutely jammed solid.
0:55:59 > 0:56:02So we're going to take the engine apart this afternoon
0:56:02 > 0:56:03and see what's broken.
0:56:03 > 0:56:06In the middle of the French countryside, any rescue,
0:56:06 > 0:56:09however unusual, is extremely welcome.
0:56:16 > 0:56:18Just looking at the top, the piston crown,
0:56:18 > 0:56:22the bit at the top, is all hammered and dented.
0:56:22 > 0:56:24Anyway, it's given up.
0:56:24 > 0:56:26The engine isn't repairable,
0:56:26 > 0:56:29so the team resort to the backup microlight.
0:56:31 > 0:56:33And with it comes a new dose of luck.
0:56:39 > 0:56:42With some perfect turns from Christian,
0:56:42 > 0:56:45Richard finally gets eye-to-eye with a flying flock of cranes.
0:56:48 > 0:56:52And after all they've been through, the team are truly delighted.
0:56:55 > 0:56:57But even with the latest technology
0:56:57 > 0:57:01and some resourceful individuals, we only get the briefest window
0:57:01 > 0:57:04into the world of these amazing creatures.
0:57:06 > 0:57:09And this only highlights just what an achievement it is
0:57:09 > 0:57:11to spend your life in the skies.
0:57:16 > 0:57:21Next time, we'll discover that the skies are crowded
0:57:21 > 0:57:23full of creatures in a battle for survival.
0:57:26 > 0:57:29There's competition for mates,
0:57:29 > 0:57:31for food...
0:57:33 > 0:57:36..and even for life itself.
0:57:38 > 0:57:40Only the best flyers need apply.