0:00:33 > 0:00:38If a James Bond villain tired of his struggle for world domination
0:00:38 > 0:00:43this is the sort of tomato-growing business he might set up.
0:00:43 > 0:00:45A sea of glass where light, heat,
0:00:45 > 0:00:51even the mix of gases in the atmosphere is computer controlled.
0:00:52 > 0:00:58Inside, 53 million tomatoes are cultivated every year.
0:01:01 > 0:01:07But space-age science aside, for a tomato flower to turn into a tomato,
0:01:07 > 0:01:09it needs a good shake.
0:01:09 > 0:01:14Only then will pollen be released and the flower fertilised.
0:01:14 > 0:01:17And to do that to so many flowers
0:01:17 > 0:01:21you'd expect a gadget worthy of 007 himself.
0:01:23 > 0:01:25The truth is far simpler.
0:01:25 > 0:01:28The thing that came to the tomato grower's aid
0:01:28 > 0:01:31was something all this technology couldn't hope to match.
0:01:31 > 0:01:35Something that was turning flowers into fruits
0:01:35 > 0:01:36when it was just dawning on us
0:01:36 > 0:01:39that coming down from the trees might be a good idea.
0:01:39 > 0:01:41And that something is in there.
0:01:43 > 0:01:45BUZZING
0:01:47 > 0:01:50The humble bumblebee.
0:01:50 > 0:01:53Every time you bite into a cheese and tomato sandwich,
0:01:53 > 0:01:56chances are you have one of these to thank.
0:01:56 > 0:02:01Without them, most of Britain's tomatoes would wither on the vine.
0:02:04 > 0:02:08The secret is in the buzz.
0:02:08 > 0:02:12When a bumblebee visits a flower, it disengages its wings
0:02:12 > 0:02:15and runs its powerful flight muscles in neutral,
0:02:15 > 0:02:18becoming...the perfect vibrator.
0:02:20 > 0:02:23Listen...
0:02:23 > 0:02:25pollination.
0:02:25 > 0:02:27VIBRATING BUZZ
0:02:30 > 0:02:34These enormous glasshouses were built partly to exclude wildlife.
0:02:34 > 0:02:39And yet the success of Britain's hi-tech multi-million pound farms
0:02:39 > 0:02:41relies on bringing it back in!
0:02:41 > 0:02:45Every year, two and a half million bumblebees are set to work
0:02:45 > 0:02:50in Britain's glasshouses to make tomatoes for us.
0:02:50 > 0:02:55The bee and the tomato show us how vital wildlife can be for farmers,
0:02:55 > 0:02:59and yet with changing farming practices
0:02:59 > 0:03:01wild creatures have often suffered.
0:03:04 > 0:03:08But if we can't find space for nature on our farms,
0:03:08 > 0:03:10there isn't a lot of room left.
0:03:10 > 0:03:13Farmland makes up at least three quarters
0:03:13 > 0:03:15of the entire British Isles.
0:03:15 > 0:03:19So join me, as we explore whether we can both grow food,
0:03:19 > 0:03:23and find space for nature on our farmland.
0:03:27 > 0:03:30Wildlife has had a place on our farms
0:03:30 > 0:03:34ever since farming began in Britain, 5,000 years ago.
0:03:34 > 0:03:37I've come to Norfolk to see a creature
0:03:37 > 0:03:41that probably arrived following those first Neolithic farmers.
0:03:41 > 0:03:44And with 40,000 about to turn up,
0:03:44 > 0:03:49I'm afraid you, my friend, don't stand a chance. Evening...
0:04:00 > 0:04:02Look at that.
0:04:02 > 0:04:06It's a chilly November evening, the sun's just setting,
0:04:06 > 0:04:09and I want to share with you one of the most overlooked
0:04:09 > 0:04:11wildlife spectacles in Britain,
0:04:11 > 0:04:17and a perfect demonstration of how tied up wildlife is with farmland.
0:04:17 > 0:04:18The only thing is,
0:04:18 > 0:04:22I'm not quite sure where they're going to come from.
0:04:29 > 0:04:34The sounds of November twilight in Norfolk. Listen...
0:04:34 > 0:04:37pheasants going to roost over there in the woods,
0:04:37 > 0:04:40- but over there behind me... - CAWING
0:04:40 > 0:04:45..far more birds, making a far greater sound. A crowd's gathering.
0:04:45 > 0:04:49Now then, look, just spotted a load over there.
0:04:49 > 0:04:51By that big old oak tree.
0:04:51 > 0:04:55D'you see? To the left. Whoo! They look like starlings but they're not.
0:04:55 > 0:05:00They're much, much bigger than starlings. Now, we're in Norfolk.
0:05:00 > 0:05:02And there's a saying in Norfolk.
0:05:02 > 0:05:05"When thass a rook, thass a crow,
0:05:05 > 0:05:08"and when thass crows, thass rooks."
0:05:08 > 0:05:12What that means, in Queen's English, is that if you see one,
0:05:12 > 0:05:14it's likely to be a crow,
0:05:14 > 0:05:17and if you see a great flock of them they're rooks, cos rooks flock,
0:05:17 > 0:05:21and these rooks are flocking like no rooks you've ever seen.
0:05:22 > 0:05:24They're all gathering.
0:05:28 > 0:05:31And I promise you, when this happens...
0:05:31 > 0:05:33it's a spectacle to remember.
0:05:36 > 0:05:38Rooks are birds of open country
0:05:38 > 0:05:43so as ancient farmers cleared the woodland, they flourished.
0:05:43 > 0:05:46They spend the day feeding in the fields.
0:05:46 > 0:05:52But as dusk falls they fly in to their night-time roost.
0:05:52 > 0:05:54And this is one of the biggest in Britain.
0:05:57 > 0:06:01Some people think they gather like this to share information,
0:06:01 > 0:06:05somehow letting each other know about the best winter feeding spots.
0:06:07 > 0:06:10It really does sound as though they might be chatting!
0:06:10 > 0:06:13But before long they fall silent.
0:06:14 > 0:06:17They're waiting for a signal...
0:06:17 > 0:06:19and so am I.
0:06:22 > 0:06:25It's hard to believe anything's going to happen at all.
0:06:25 > 0:06:28But listen.
0:06:30 > 0:06:33FLAPPING AND CAWING
0:06:41 > 0:06:44ROOKS CALL
0:06:49 > 0:06:52A swirling mass,
0:06:52 > 0:06:54thousands of them.
0:06:54 > 0:06:57You can almost hear their wings beating the air.
0:06:57 > 0:06:59You CAN hear them.
0:06:59 > 0:07:02Goodness me.
0:07:09 > 0:07:11Can you hear it building and building?
0:07:11 > 0:07:15There's more and more. Thousands of them.
0:07:18 > 0:07:20It's astonishing.
0:07:24 > 0:07:26Just astonishing.
0:07:38 > 0:07:40What a noise!
0:07:40 > 0:07:42And still they're coming.
0:07:42 > 0:07:46They're still flocking in from behind this big oak tree.
0:07:46 > 0:07:49Look at that. Have you ever seen anything like that?
0:08:04 > 0:08:08They'll wheel around over these trees, then suddenly,
0:08:08 > 0:08:11they'll drop and roost for the night.
0:08:11 > 0:08:13What a noise, eh?
0:08:23 > 0:08:26They're all going down now,
0:08:26 > 0:08:29nestling down into the trees.
0:08:30 > 0:08:3420 minutes to five. Bedtime for them!
0:08:34 > 0:08:37I think I fancy something warming.
0:08:37 > 0:08:41The rooks have only flourished because of farmland,
0:08:41 > 0:08:43feeding on insects and worms
0:08:43 > 0:08:46found in the pasture and revealed by the plough,
0:08:46 > 0:08:49and the seed the farmer sows to grow as crops.
0:08:52 > 0:08:57But it's not just planting crops that has a big impact on our wildlife.
0:08:57 > 0:09:01The timing of their growth is also critical.
0:09:08 > 0:09:13The hare was a relative latecomer to our farming landscape,
0:09:13 > 0:09:19appearing around the time of the Romans when much of Britain was already farmed.
0:09:19 > 0:09:23In this Hertfordshire countryside, it's early spring,
0:09:23 > 0:09:27and the crops are just pushing their new shoots through the soil.
0:09:27 > 0:09:32That's when the hares' nerves start to tense, their pulses quicken
0:09:32 > 0:09:37and they prepare to sort things out like gentlemen.
0:09:37 > 0:09:39Queensberry rules?
0:09:39 > 0:09:41I don't think so.
0:10:01 > 0:10:03Hares are here in such numbers
0:10:03 > 0:10:06because of the timing of the crops' growth.
0:10:06 > 0:10:10Hares only eat the youngest and freshest shoots
0:10:10 > 0:10:13so numbers have declined on farms with only one crop
0:10:13 > 0:10:18as that soon becomes too old to eat.
0:10:18 > 0:10:22Crucially, these fields are surrounded by a mix of crops,
0:10:22 > 0:10:24ensuring that at any time of year,
0:10:24 > 0:10:29there's always something young and tasty to be found.
0:10:33 > 0:10:38On a traditional farm it's easier for the hare and other wildlife
0:10:38 > 0:10:41to find food and shelter throughout the year.
0:10:41 > 0:10:47And this patchwork quilt also has a beautiful impact on our British landscape.
0:11:03 > 0:11:08The intense yellow of oilseed rape.
0:11:08 > 0:11:12The oil from its crushed seeds is used in margarine, livestock feed
0:11:12 > 0:11:17and more recently in biodiesel, fuelling the nation's tractors -
0:11:17 > 0:11:22both the traditional and Chelsea varieties.
0:11:24 > 0:11:26Golden fields...
0:11:26 > 0:11:29of wheat milled to make flour.
0:11:29 > 0:11:32Or barley, only the very best of which,
0:11:32 > 0:11:34in true British fashion,
0:11:34 > 0:11:37is used to make beer or whisky.
0:11:38 > 0:11:41Then there's the delicate pale blue of linseed,
0:11:41 > 0:11:44one of our oldest cultivated crops.
0:11:44 > 0:11:48Its oil is used in paints, printing inks,
0:11:48 > 0:11:50and of course, most importantly,
0:11:50 > 0:11:54to keep the bats of our nation's cricketers well-oiled.
0:11:59 > 0:12:03Then, just occasionally, if you're lucky,
0:12:03 > 0:12:06a field of bright and vivid blood red.
0:12:06 > 0:12:08A mass of poppies,
0:12:08 > 0:12:12so striking you'd think it had been planted on purpose.
0:12:16 > 0:12:20But what's so wonderful about our farming landscape
0:12:20 > 0:12:25is the slow and subtle change in these colours
0:12:25 > 0:12:28with the passing of the seasons.
0:12:28 > 0:12:32It means that every time we stare out of a window,
0:12:32 > 0:12:34go for a stroll in the countryside,
0:12:34 > 0:12:37or glance out of a passing car, we see something new.
0:12:39 > 0:12:42And when you see this colourful backdrop,
0:12:42 > 0:12:46with smaller fields and hedgerows that have been planted or preserved,
0:12:46 > 0:12:49it's more than likely that this diversity
0:12:49 > 0:12:54is benefiting the wildlife, as well as being beautiful for us.
0:12:58 > 0:13:03We've seen how crops and the timing of their growth have an impact on the landscape.
0:13:03 > 0:13:08But there's another way in which scattering seed can influence the British countryside -
0:13:08 > 0:13:12without it ever growing! Just come and look at this.
0:13:13 > 0:13:18There's a little trailer on the back of this Land Rover and inside it is corn.
0:13:18 > 0:13:23If I just pull that little trap door up there, and then turn on this.
0:13:23 > 0:13:25Now watch yourself.
0:13:25 > 0:13:27Out comes the corn.
0:13:27 > 0:13:30Do you want to hop in and I'll show you what happens?
0:13:34 > 0:13:38This vehicle has been specially modified to sow seed.
0:13:38 > 0:13:43Not in carefully ploughed furrows or fertilised fields,
0:13:43 > 0:13:45but just wherever it goes.
0:13:55 > 0:13:59Every year, thousands of tonnes of seed is sown in Britain,
0:13:59 > 0:14:01where it hasn't the slightest chance of growing.
0:14:01 > 0:14:05It's scattered at the edges of fields and down country lanes.
0:14:05 > 0:14:08Onto roadside verges and at the bottom of hedgerows.
0:14:08 > 0:14:15In fact, on some farms, more seed is used like this, than is sown to grow as crops.
0:14:15 > 0:14:18But this seed isn't being sown to grow at all.
0:14:18 > 0:14:22It's being sown as feed.
0:14:22 > 0:14:26It's for an creature that entire woodlands are planted for,
0:14:26 > 0:14:28hedgerows are managed for,
0:14:28 > 0:14:32and for which plants as alien as pampas grass are lovingly tended
0:14:32 > 0:14:36in order to afford it some protection from the winter elements.
0:14:40 > 0:14:42That ought to do it.
0:14:42 > 0:14:48I'm waiting for a creature that's had an enormous impact on the British landscape,
0:14:48 > 0:14:51even though it's nearest natural home is 2,000 miles away.
0:14:51 > 0:14:55And if you wait a minute or two, you'll see it.
0:15:08 > 0:15:09There you go.
0:15:11 > 0:15:14The pheasant can seem impossibly exotic,
0:15:14 > 0:15:18and yet its call is an evocative part of the British countryside.
0:15:18 > 0:15:21PHEASANT CALLS
0:15:21 > 0:15:26Most of us only get a glimpse as we swerve to avoid one in the car.
0:15:26 > 0:15:29But let me share with you its secret life,
0:15:29 > 0:15:32just beyond these Dorset hedgerows.
0:15:32 > 0:15:38In March, you'll find the males crowing and strutting like the local landowners
0:15:38 > 0:15:42as they attempt to woo a harem of broody females.
0:15:47 > 0:15:51But not before they've seen off the local competition.
0:16:24 > 0:16:27Once the hierarchy has been established,
0:16:27 > 0:16:31the male approaches the female with his head bowed low.
0:16:35 > 0:16:37He fans his showy tail feathers
0:16:37 > 0:16:42and angling his body to show off his golden plumage.
0:17:15 > 0:17:20The nearest natural home of this exotic bird is south-west Asia.
0:17:20 > 0:17:25So how has it come to influence our British landscape so greatly?
0:17:25 > 0:17:29Well, the fact is that large areas of our countryside
0:17:29 > 0:17:34are managed or preserved to encourage pheasants for shooting.
0:17:34 > 0:17:37Whatever your feelings about this controversial pursuit,
0:17:37 > 0:17:42managing land for pheasants can benefit other wildlife.
0:17:42 > 0:17:45The grain feeds songbirds, and cover crops ensure
0:17:45 > 0:17:49that farmland birds have shelter and food during the winter.
0:17:49 > 0:17:56Historically, pheasants have also been an important reason for planting and managing woodlands,
0:17:56 > 0:17:58and their rides and glades
0:17:58 > 0:18:03encourage butterflies like the silver-washed fritillary.
0:18:03 > 0:18:07They may invite controversy but the impact of country pursuits
0:18:07 > 0:18:10on our landscape isn't always clear-cut.
0:18:10 > 0:18:14Pheasants might have had a surprising influence on our landscape
0:18:14 > 0:18:19but their impact is tiny when compared with another group of creatures
0:18:19 > 0:18:23that have been slowly shaping Britain for thousands of years.
0:18:23 > 0:18:27Without them, Vaughan Williams might never have composed the Lark Ascending,
0:18:27 > 0:18:31nor William Blake penned Jerusalem.
0:18:35 > 0:18:42And did the countenance divine shine forth upon our clouded hills?
0:18:44 > 0:18:46You bet it did.
0:18:55 > 0:19:01But who are these unsung heroes of Britain's green and pleasant land?
0:19:05 > 0:19:11It's Britain's 10 million cows and 35 million sheep.
0:19:11 > 0:19:17Without them, Britain wouldn't be a green and pleasant land at all.
0:19:17 > 0:19:21The cows are brought into barns to spend the winter.
0:19:21 > 0:19:28For months, they wait for the opportunity to be out in the fields again.
0:19:35 > 0:19:40Until, in early spring, the day finally arrives
0:19:40 > 0:19:43when they're let loose once again.
0:20:23 > 0:20:27The cows are so excited that they gambol like lambs.
0:20:27 > 0:20:31And all because of this - grass.
0:20:31 > 0:20:38It's our livestock's need to eat fresh grass that creates Britain's pastoral landscapes.
0:20:38 > 0:20:42And it's by eating nothing but this simplest of plants
0:20:42 > 0:20:45that each cow is capable of producing
0:20:45 > 0:20:4811,000 pints of milk a year.
0:20:48 > 0:20:52To fill the new Wembley stadium to the brim,
0:20:52 > 0:20:55it would take Britain's cows just over a month.
0:21:05 > 0:21:10All these animals eating all this grass
0:21:10 > 0:21:13has one inevitable conclusion.
0:21:13 > 0:21:18Feeding the livestock ends up feeding the land.
0:21:18 > 0:21:21Dung - it's amazing stuff.
0:21:21 > 0:21:26I mean, you only have to crouch down by a fresh pat on a summer's day -
0:21:26 > 0:21:29thank you - to understand why.
0:21:29 > 0:21:33You'd probably rather go off for a brisk walk to get out of their way,
0:21:33 > 0:21:38or tuck into a cream tea, but bear with me, it's quite gripping.
0:21:47 > 0:21:51You wouldn't believe what lives on this stuff.
0:21:51 > 0:21:54The whole pat is crawling with life.
0:22:01 > 0:22:05On the surface, a fungal forest develops.
0:22:16 > 0:22:21Who would have thought that dung could be so beautiful?
0:22:42 > 0:22:46But by the time they're ready to shed their spores,
0:22:46 > 0:22:49something rather unfortunate has happened.
0:22:53 > 0:22:57Nourished by the dung, the grass grows tall and thick.
0:22:57 > 0:23:02Anything wanting to escape finds itself surrounded by a wall of grass.
0:23:02 > 0:23:06This fungus, barely a few millimetres high,
0:23:06 > 0:23:08has to disperse its spores.
0:23:08 > 0:23:12But now that this grass has grown, that would be like you or me
0:23:12 > 0:23:15trying to throw a tennis ball over Blackpool Tower.
0:23:15 > 0:23:20But this fine covering of velvet is no ordinary fungus.
0:23:20 > 0:23:22This is the hat-throwing fungus.
0:23:22 > 0:23:26Watch it and you'll see why.
0:23:30 > 0:23:33On top of each tiny stalk sits a black 'hat'
0:23:33 > 0:23:36containing the fungal spores.
0:23:36 > 0:23:40And guided by a light sensitive 'eye' they take careful aim,
0:23:40 > 0:23:44lining themselves up with gaps between the grass stems.
0:23:44 > 0:23:48Inside, the pressure builds until...
0:23:54 > 0:23:59Blink and you've missed it - even slowed down almost 500 times.
0:24:02 > 0:24:06Spores are fired as far as 12 feet,
0:24:06 > 0:24:10and even over the heads of nearby cows!
0:24:10 > 0:24:15Once the spores have landed on fresh grass, they'll be eaten,
0:24:15 > 0:24:17passed through the cow's gut
0:24:17 > 0:24:21and deposited in their own personal pile of manure.
0:24:21 > 0:24:23Hitting the ground growing, you might say.
0:24:23 > 0:24:29If it weren't for the army of insects and fungi breaking down the dung,
0:24:29 > 0:24:32then not only would we be knee deep in the stuff,
0:24:32 > 0:24:36but crucially, all the goodness would remain locked up inside it,
0:24:36 > 0:24:39instead of being released back into the soil.
0:24:39 > 0:24:42And the impact of dung on our farmland wildlife
0:24:42 > 0:24:45is further-reaching than you might think.
0:24:50 > 0:24:54Britain's cows don't just provide milk and meat.
0:24:54 > 0:24:59Their dung is also an incredible source of food for Britain's creepy-crawlies.
0:25:02 > 0:25:07Each cowpat may nurture 1,000 developing insects.
0:25:07 > 0:25:11And the constant drone of flies and sound of swishing tails
0:25:11 > 0:25:15accompanies every evening spent in summer pasture.
0:25:15 > 0:25:20Just through its dung every cow may increase the insect population
0:25:20 > 0:25:24in its home range by up to three million.
0:25:24 > 0:25:28Forget beef - in just four years
0:25:28 > 0:25:32a cow can nurture its own body weight in mini-beasts!
0:25:32 > 0:25:34And for some birds,
0:25:34 > 0:25:38that's a feast worth travelling all the way from Africa to enjoy.
0:25:41 > 0:25:46Where would our farmland be, without swallows hawking over the fields?
0:26:03 > 0:26:07And on hot summer days, they'll wash down their meal
0:26:07 > 0:26:10with a drink taken on the wing.
0:26:35 > 0:26:40But dung doesn't only provide for these iconic farmland birds.
0:26:40 > 0:26:42Without the right sort of dung
0:26:42 > 0:26:45we nearly lost one of our rarest mammals.
0:26:45 > 0:26:49But to see that, and to find out how,
0:26:49 > 0:26:52we'll have to wait for nightfall.
0:27:08 > 0:27:12These are the original dumbledores.
0:27:12 > 0:27:17An old and often forgotten name for dung beetles.
0:27:17 > 0:27:20At night, they take to the air,
0:27:20 > 0:27:26in search of pastures new and the fresh dung they bring.
0:27:26 > 0:27:29But beetles beware - hanging in the foliage
0:27:29 > 0:27:33is something with a particular taste for dumbledors.
0:27:36 > 0:27:39The greater horseshoe bat.
0:27:41 > 0:27:46It sends ultrasonic squeaks through that horseshoe-shaped nose
0:27:46 > 0:27:51then listens for the telltale echoes of its prey,
0:27:51 > 0:27:56turning its head and scanning with its ears to pinpoint the smallest wing beat.
0:28:02 > 0:28:05It's a large and reluctant flier.
0:28:05 > 0:28:09And only when something passes by its preferred feeding perch
0:28:09 > 0:28:12will it take to the wing in pursuit.
0:28:45 > 0:28:47COWS MOO
0:29:13 > 0:29:18It hunts a host of nocturnal insects in utter silence.
0:29:18 > 0:29:21No beetle or moth is safe.
0:29:43 > 0:29:49Greater horseshoe bats had all but disappeared from our countryside
0:29:49 > 0:29:52before it was realised how important the cows were to them.
0:29:52 > 0:29:56When cows were routinely given drugs to cure them of worms,
0:29:56 > 0:29:59the dung beetles were killed too.
0:29:59 > 0:30:02And without the beetles, the bats starve.
0:30:02 > 0:30:05But a growing awareness of the importance of beetles to bats
0:30:05 > 0:30:09led farmers to change their practices,
0:30:09 > 0:30:12hopefully ensuring their survival.
0:30:20 > 0:30:26It's not just through their dung that livestock influence our farmland habitats.
0:30:26 > 0:30:31One of our rarest species relies on farm animals in a way so bizarre,
0:30:31 > 0:30:33you couldn't make it up.
0:30:35 > 0:30:38For a few weeks each year,
0:30:38 > 0:30:42Large Blue butterflies mate and lay their eggs.
0:30:52 > 0:30:55Meadow ants nesting in the grass
0:30:55 > 0:30:58are an irritant for the adults,
0:30:58 > 0:31:01but an unlikely asset for their tiny caterpillars.
0:31:02 > 0:31:06You see, the Large Blues have a rather interesting approach
0:31:06 > 0:31:11to parental care. Their young are adopted by ants.
0:31:13 > 0:31:17The caterpillar mimics the sound and smell of the ant's own young.
0:31:17 > 0:31:23And, mistaken for a mislaid ant larva, is taken back to the nest
0:31:23 > 0:31:24by the foraging workers.
0:31:24 > 0:31:27But it doesn't repay the favour.
0:31:27 > 0:31:31Once underground, the caterpillar leads a predatory life,
0:31:31 > 0:31:33eating the ants' own larvae,
0:31:33 > 0:31:37until one day it's ready to change into a pupa...
0:31:39 > 0:31:44..and eventually emerges as one of our rarest butterflies.
0:31:47 > 0:31:49Ants are vital to the butterfly
0:31:49 > 0:31:53but they're very particular about the kind of grass they like.
0:31:53 > 0:31:56Too long and they move out.
0:31:56 > 0:32:01So without the sheep to keep the grass short, there would be no ants.
0:32:01 > 0:32:04And without the ants, the Large Blue would be lost.
0:32:07 > 0:32:12If allowed to overgraze, livestock can damage our farmland habitats
0:32:12 > 0:32:14but the story of the Large Blue
0:32:14 > 0:32:18shows us how carefully-managed munching is vital.
0:32:19 > 0:32:26So livestock influences both our wildlife and landscape through its dung and grazing,
0:32:26 > 0:32:31but our need to control farm animals also has an enormous impact.
0:32:31 > 0:32:36To find out how, I've come to the remote island of North Ronaldsay,
0:32:36 > 0:32:40home to the tallest mainland lighthouse in Britain
0:32:40 > 0:32:44and a famous bird observatory.
0:32:47 > 0:32:52All these things are worth travelling to the northernmost reaches of our islands to see,
0:32:52 > 0:32:56but I'm here to see something else.
0:32:57 > 0:33:00A wall. But not just any wall.
0:33:00 > 0:33:05North Ronaldsay is home to Britain's very own "Great Wall".
0:33:05 > 0:33:08It might not be a match for the Great Wall of China,
0:33:08 > 0:33:15but at 13 miles long, this is the longest, continuous, dry-stone structure in the world.
0:33:18 > 0:33:21It surrounds the entire island,
0:33:21 > 0:33:25making it one of the most bizarre field boundaries in Britain.
0:33:25 > 0:33:27But why was it built?
0:33:27 > 0:33:30Well, the weather here can be merciless.
0:33:30 > 0:33:33Gales rage in across the North Sea,
0:33:33 > 0:33:38and on a spring high tide the water threatens to flood the low-lying fields.
0:33:41 > 0:33:47A great wall is just what the local livestock need to protect them from the treacherous Orkney weather.
0:33:47 > 0:33:50But you won't find them sheltering here in the fields.
0:33:50 > 0:33:53The wall wasn't designed to keep them safe on the farm.
0:33:53 > 0:33:55It was built to keep them out...
0:33:58 > 0:34:03200 years ago the sheep were thrown off the fields to make way for more profitable cattle.
0:34:03 > 0:34:08This need to control the livestock created a farm animal
0:34:08 > 0:34:12that can survive eating nothing but seaweed.
0:34:12 > 0:34:17And there's only one other large land animal in the world that can do that.
0:34:17 > 0:34:19The marine iguana on the Galapagos.
0:34:19 > 0:34:24In fact, these sheep are so used to eating seaweed
0:34:24 > 0:34:28that if they eat too much grass it poisons them!
0:34:28 > 0:34:33Banished by the boundary, their lives are dictated entirely by the rhythms of the ocean.
0:34:33 > 0:34:38They graze at each low tide, whether it's day or night.
0:34:38 > 0:34:42But it's not just here on North Ronaldsay
0:34:42 > 0:34:45that the need to control livestock influences the landscape.
0:34:45 > 0:34:52The entire British Isles is a patchwork quilt of fields defined by their boundaries.
0:34:54 > 0:34:59Although perhaps less of a patchwork than it once was.
0:34:59 > 0:35:04Walls and hedgerows have really suffered since the last war.
0:35:04 > 0:35:09With the pressure on to feed the nation, field boundaries just got in the way.
0:35:14 > 0:35:19Incredibly, since 1945, the length of the hedgerows
0:35:19 > 0:35:24lost from the British landscape would stretch almost to the moon.
0:35:26 > 0:35:29But the decline has now halted,
0:35:29 > 0:35:32which is fantastic news for our wildlife.
0:35:32 > 0:35:37Not least because, for many creatures, the hedgerow is home.
0:35:37 > 0:35:40Fields are often difficult places to live.
0:35:40 > 0:35:45Crops are harvested and meadows regularly mown.
0:35:45 > 0:35:48But hedgerows, walls and rough grassland
0:35:48 > 0:35:50provide opportunities for wildlife.
0:35:50 > 0:35:55Including, pound for pound, Britain's most fearsome carnivore.
0:35:58 > 0:36:00The stoat.
0:36:02 > 0:36:05An old dry-stone wall provides the perfect den.
0:36:08 > 0:36:13And the meadow attracts the prey.
0:36:44 > 0:36:45SQUEALING
0:36:54 > 0:36:59So field boundaries can be important homes for wildlife,
0:36:59 > 0:37:01but they play another, very different role,
0:37:01 > 0:37:04one that can directly benefit the farmer.
0:37:08 > 0:37:14This young and succulent crop is about to come under attack.
0:37:14 > 0:37:16And once the enemy arrives,
0:37:16 > 0:37:19it's almost unstoppable.
0:37:20 > 0:37:24This is a sight that every farmer dreads.
0:37:24 > 0:37:30A winged aphid lands on a wheat stem and prepares to start a family.
0:37:30 > 0:37:35A famous biologist once calculated that if they all survived,
0:37:35 > 0:37:40after ten generations, a single aphid could produce a weight of insects
0:37:40 > 0:37:44equal to 500 million people.
0:37:45 > 0:37:50Like Russian dolls, an aphid develops inside its own grandmother.
0:37:50 > 0:37:54If you look inside, you can even see their eyes.
0:37:54 > 0:37:58One winged individual arrives, and before you know it,
0:37:58 > 0:38:03there's an army of clones sucking the life out of your crop.
0:38:04 > 0:38:10But the secret to controlling them might lie in the simplest of things.
0:38:11 > 0:38:15The field margin's flowers and rough grassland
0:38:15 > 0:38:18attract one of our best-loved insects.
0:38:18 > 0:38:25As every gardener knows, there's nothing better than a ladybird to keep the aphids in check.
0:38:25 > 0:38:27Or is there?
0:38:31 > 0:38:34Ladybirds and their larvae do eat aphids,
0:38:34 > 0:38:36but many fly in from the continent each year,
0:38:36 > 0:38:40arriving too late to have a real impact.
0:38:40 > 0:38:45And when they do arrive, they scare more aphids than they eat.
0:38:46 > 0:38:49The pests just drop off the plant,
0:38:49 > 0:38:52wait for the ladybird to bumble on,
0:38:52 > 0:38:54and then return to feed.
0:39:00 > 0:39:05Fortunately, there are unsung heroes on our farmland.
0:39:05 > 0:39:11It's real saviour is an army of parachuting predators that are easy to overlook.
0:39:15 > 0:39:16They're the money spiders,
0:39:16 > 0:39:19and they carry a secret weapon
0:39:19 > 0:39:22that allows them to attack from the air.
0:39:29 > 0:39:34Other wingless predators have difficulty venturing far into the crop.
0:39:34 > 0:39:37But clinging to lines of silk,
0:39:37 > 0:39:41the spiders are boldly carried forth into the battle zone,
0:39:41 > 0:39:46right into the middle of the field. When they land, they set to work,
0:39:46 > 0:39:49spinning a silken safety net.
0:39:49 > 0:39:52Once its done, they wait for the prey to drop in,
0:39:52 > 0:39:56often aided by the bumbling ladybirds.
0:40:07 > 0:40:13The hedgerows are strewn with their parachuting lines.
0:40:14 > 0:40:19Each and every one representing an aphid-eating predator on the attack.
0:40:22 > 0:40:28Our reliance on pesticides has made us forget the importance of the aphids' natural predators.
0:40:28 > 0:40:32But planting field margins not only attracts and shelters
0:40:32 > 0:40:36aphid-munching mini-beasts, but also bees
0:40:36 > 0:40:40and other insects which pollinate our crops.
0:40:40 > 0:40:44These flowers may never replace pesticides completely,
0:40:44 > 0:40:50but where they do, our countryside is a far prettier place to be,
0:40:50 > 0:40:52and a lot better for wildlife.
0:40:56 > 0:41:00But field boundaries can also be made of water.
0:41:00 > 0:41:04In some regions of Britain, these have a more important function
0:41:04 > 0:41:07than simply controlling the livestock.
0:41:09 > 0:41:14When the Anglo Saxons invaded this area in the 7th century,
0:41:14 > 0:41:18they named it Somerset - "land of the summer people".
0:41:18 > 0:41:23Not because the Celts they conquered were of a particularly sunny disposition,
0:41:23 > 0:41:29but because the land flooded in winter and the only time the locals could cultivate it was in summer.
0:41:29 > 0:41:32At that time, Glastonbury - just over there,
0:41:32 > 0:41:34King Arthur's Isle of Avalon -
0:41:34 > 0:41:37really was an island.
0:41:38 > 0:41:43Over time, thousands of ditches were built to drain the land.
0:41:43 > 0:41:47But after centuries of trying to exclude water,
0:41:47 > 0:41:50man is finally allowing nature to take its course.
0:41:50 > 0:41:53The land is only farmed in the summer.
0:41:53 > 0:41:55In winter, it belongs to the birds.
0:41:56 > 0:42:04On the Somerset Levels, water from the ditches is once again being allowed to rise and flood the land.
0:42:04 > 0:42:08And this traditional farming practice gives us one of Britain's
0:42:08 > 0:42:11most dramatic wildlife spectacles.
0:42:14 > 0:42:18The water brings nutrient-rich sediments,
0:42:18 > 0:42:21and they draw in huge numbers of wildfowl.
0:42:25 > 0:42:30And all these birds in one place are bound to attract attention.
0:42:43 > 0:42:48The attention of the fastest creature on the planet -
0:42:48 > 0:42:50the peregrine falcon.
0:42:54 > 0:42:59Its tapering wings give it incredible speed and agility,
0:42:59 > 0:43:04but its feathers lack the oils which keep the water off the ducks' backs.
0:43:04 > 0:43:10If it gets wet it'll be unable to fly, and in deep water could drown.
0:43:26 > 0:43:31If they just take to the air, the ducks would be easy prey.
0:43:31 > 0:43:34They know their safest option is to stay low,
0:43:34 > 0:43:37and if they have to, dive for cover.
0:43:55 > 0:43:58This kind of hunting is difficult.
0:43:58 > 0:44:01The peregrine daren't risk a dunking.
0:44:05 > 0:44:09Its only chance is to fly at the flock so fast
0:44:09 > 0:44:11that the ducks take to the air.
0:44:11 > 0:44:16If they're driven high enough, it can hit them from above.
0:44:30 > 0:44:34But this close to the ground, it's a risky strategy.
0:44:42 > 0:44:45Eventually, it picks a likely target
0:44:45 > 0:44:48and turns to stoop.
0:44:48 > 0:44:50At incredible speed,
0:44:50 > 0:44:52it hurtles toward the water.
0:44:57 > 0:45:02It misses, but in the confusion separates one bird from the flock.
0:45:09 > 0:45:12As the dazed bird takes to the air,
0:45:12 > 0:45:16the peregrine finally seizes its chance.
0:45:52 > 0:45:56No matter how important our farmland is for wildlife,
0:45:56 > 0:45:58we mustn't forget what it's for...
0:45:58 > 0:46:00producing food.
0:46:03 > 0:46:08And there comes a time when we all reap the benefits.
0:46:12 > 0:46:14Harvest.
0:46:23 > 0:46:28Farmers work around the clock to gather in a few days
0:46:28 > 0:46:32what may have taken a year to prepare and grow.
0:46:35 > 0:46:41For thousands of years, this has been a time of celebration.
0:46:41 > 0:46:45A time when communities come together to give thanks
0:46:45 > 0:46:48for the bounty of our British landscape.
0:46:50 > 0:46:53Although, for our farmland wildlife,
0:46:53 > 0:46:56there hasn't always been much to celebrate.
0:47:01 > 0:47:06We all know farmland is a working landscape, not a nature reserve.
0:47:06 > 0:47:11But now, as we no longer need to farm so intensively,
0:47:11 > 0:47:15there's a growing opportunity to farm sensitively.
0:47:15 > 0:47:21And understanding the relationship between the farm and its wildlife
0:47:21 > 0:47:25can help ensure a place both for nature, and for food.
0:47:26 > 0:47:31Farmland isn't just part of the British countryside,
0:47:31 > 0:47:33it IS the British countryside.
0:47:33 > 0:47:39So if we can't find space for nature there, well...
0:47:39 > 0:47:41there isn't a lot of room left.
0:47:41 > 0:47:44So the next time you tuck into granary bread,
0:47:44 > 0:47:49a crisp Cox's apple or a proper Ploughman's lunch,
0:47:49 > 0:47:52be thankful. But spare a thought.
0:47:52 > 0:47:56On the land where our farmers nurtured our food,
0:47:56 > 0:47:59was there room to be found
0:47:59 > 0:48:01for the nature of Britain?