0:00:05 > 0:00:08The UK is wilder than you may think.
0:00:08 > 0:00:11Just 3% of this land has been built upon
0:00:11 > 0:00:15and so there are plenty of world-class wild spaces -
0:00:15 > 0:00:17and incredible wildlife.
0:00:17 > 0:00:18I'm Colin Stafford-Johnson.
0:00:18 > 0:00:19And I'm Lucy Cooke.
0:00:19 > 0:00:23And every day we're going to be discovering the top wilderness spots
0:00:23 > 0:00:28in the UK and revealing just how wild our islands are.
0:00:29 > 0:00:32We'll be travelling from rivers to mountains,
0:00:32 > 0:00:36from forests to seas and even to some of our wildest cities,
0:00:36 > 0:00:40celebrating the incredible range of wildlife that lives and thrives
0:00:40 > 0:00:43amongst our precious wild places.
0:00:43 > 0:00:46We'll also be going behind the scenes with Steve Backshall
0:00:46 > 0:00:48and the Wild Alaska Live team,
0:00:48 > 0:00:52covering all the wildlife action triggered by the annual arrival
0:00:52 > 0:00:56of millions of Pacific salmon to this vast wilderness.
0:00:57 > 0:00:58As a wildlife cameraman,
0:00:58 > 0:01:01I've been fortunate enough to have travelled the world,
0:01:01 > 0:01:04but the wild landscapes and wildlife of these islands
0:01:04 > 0:01:06have a special place in my heart,
0:01:06 > 0:01:09and are full of the most inspirational wildlife stories.
0:01:09 > 0:01:13And I've been passionate about protecting wildlife all my life,
0:01:13 > 0:01:17so I'm going to be joining the conservation front line
0:01:17 > 0:01:21here in the UK to learn about how we keep our wildernesses wild
0:01:21 > 0:01:24and allow our wildlife to thrive.
0:01:24 > 0:01:28This is your daily dose of the very best the UK has to offer.
0:01:28 > 0:01:30This is Wild UK.
0:01:53 > 0:01:56The UK has a wealth of wild places to choose from,
0:01:56 > 0:02:00but we're kicking off today with a look at the rich world
0:02:00 > 0:02:02of rivers and waterways.
0:02:02 > 0:02:06You can really sense the raw power of water in places like this.
0:02:06 > 0:02:10It's actually scoured out the very hole we're standing in over time
0:02:10 > 0:02:12but, at the same time,
0:02:12 > 0:02:15it adds almost a sort of hypnotic, benign quality to it.
0:02:15 > 0:02:18And, of course, they're such a crucial lifeline
0:02:18 > 0:02:21for a wide range of wildlife.
0:02:21 > 0:02:23This is the River Orchy in Scotland,
0:02:23 > 0:02:28and you might be lucky to spot otters or kingfishers or salmon here
0:02:28 > 0:02:31and that's true of waterways all across the country.
0:02:34 > 0:02:38Later, I'll be finding out how important the River Wye is
0:02:38 > 0:02:41for wild salmon returning to the UK to breed.
0:02:41 > 0:02:45What always amazes me is the fact that they have such energy left
0:02:45 > 0:02:48at the end of their long journey.
0:02:48 > 0:02:50We'll also be joined by some familiar faces
0:02:50 > 0:02:54sharing their best past experiences of the wildlife
0:02:54 > 0:02:56that relies on our rivers and waterways
0:02:56 > 0:02:59and the conservation success stories that have helped them.
0:02:59 > 0:03:01Oh! I can see it, I can see it, it's there!
0:03:01 > 0:03:04That is incredible!
0:03:04 > 0:03:09And I'll be discovering the wild side of Britain's canals.
0:03:09 > 0:03:10Oh!
0:03:10 > 0:03:12How fantastic!
0:03:12 > 0:03:15I LOVE kingfishers.
0:03:15 > 0:03:19But, first up, time for a snapshot of our rivers and waterways
0:03:19 > 0:03:22right across the UK in 2017.
0:03:24 > 0:03:27The River Severn is the UK's largest river,
0:03:27 > 0:03:33snaking its way almost 220 miles - 352km -
0:03:33 > 0:03:36from its source in the Welsh hills.
0:03:36 > 0:03:37In its lower reaches,
0:03:37 > 0:03:42it has one of the world's largest tidal ranges at 15m,
0:03:42 > 0:03:44creating the spectacular Severn bore.
0:03:46 > 0:03:48Where our major rivers empty into the sea,
0:03:48 > 0:03:51amazing wild estuaries are created.
0:03:53 > 0:03:57The UK has over 90 estuaries and is home to over a quarter
0:03:57 > 0:03:59of all the estuaries in north-west Europe.
0:04:01 > 0:04:04Morecambe Bay forms at the mouth of five rivers,
0:04:04 > 0:04:09covering a staggering 310 square kilometres, 192 square miles.
0:04:10 > 0:04:14Estuary mud teems with life and is a vital resource
0:04:14 > 0:04:16for our native and wintering birds.
0:04:18 > 0:04:21During the winter, over a third of a million birds
0:04:21 > 0:04:23can be present in the Wash.
0:04:26 > 0:04:31Almost all of the world's 200 chalk rivers are found in the UK.
0:04:31 > 0:04:33Rivers like the Itchen and Avon,
0:04:33 > 0:04:36which are home to some of our most iconic wildlife
0:04:36 > 0:04:38and are rich in invertebrate life.
0:04:40 > 0:04:44As these rivers make their way to the sea, they create
0:04:44 > 0:04:47some of the most picturesque British countryside landscapes
0:04:47 > 0:04:50and are believed to be the birthplace of fly fishing.
0:04:55 > 0:04:59Now, the UK has such a wealth of rivers and waterways,
0:04:59 > 0:05:02we'd like you to share your images and stories with us
0:05:02 > 0:05:06using social media and the hashtag #MyWilderness.
0:05:06 > 0:05:09I'm constantly amazed at the quality of photographs
0:05:09 > 0:05:12that people are getting these days with their smartphones.
0:05:12 > 0:05:15But if you want to get something a little bit fancier
0:05:15 > 0:05:18and you're by a river, think about shutter speed.
0:05:18 > 0:05:19If you use a really fast one,
0:05:19 > 0:05:22you can sort of capture the sharpness of the water
0:05:22 > 0:05:25at a moment in time, but if you use a slow one,
0:05:25 > 0:05:28then you can get that almost ghostly, ethereal,
0:05:28 > 0:05:30flowing quality of water.
0:05:32 > 0:05:37This river is especially photogenic, but actually all rivers are, really,
0:05:37 > 0:05:41and I think one of my favourites to take photos of is the River Wye,
0:05:41 > 0:05:44because you get such a variety of landscapes.
0:05:44 > 0:05:47It meanders its way through Wales and England
0:05:47 > 0:05:50and, of course, as an added bonus,
0:05:50 > 0:05:52it's one of the best places south of Scotland
0:05:52 > 0:05:55to spot a very special animal.
0:05:59 > 0:06:02The River Wye winds through the Welsh and English countryside.
0:06:04 > 0:06:06And, thanks to its unspoiled rural location,
0:06:06 > 0:06:09its wild waters are a haven for wildlife.
0:06:12 > 0:06:15There's always something to see when you hang out on the river bank.
0:06:15 > 0:06:17They just seem to attract life.
0:06:18 > 0:06:23Kingfishers, water voles, dragonflies and otters
0:06:23 > 0:06:25all call the Wye home.
0:06:29 > 0:06:32But the animal that the River Wye is most famous for
0:06:32 > 0:06:33is the Atlantic salmon.
0:06:33 > 0:06:37Now, it's also known as the king of fish and there's a good reason why.
0:06:39 > 0:06:44Adult salmon are big fish and amazing athletes.
0:06:44 > 0:06:45After years spent at sea,
0:06:45 > 0:06:48feeding off the coasts of Norway and Greenland,
0:06:48 > 0:06:51they travel thousands of miles back to the UK,
0:06:51 > 0:06:54to the very river in which they grew up,
0:06:54 > 0:06:57using their in-built map and compass.
0:06:57 > 0:07:01Their spawning grounds on the River Wye are 130 miles -
0:07:01 > 0:07:06208km - inland, but they don't make that journey all in one go.
0:07:09 > 0:07:12This section of the river is about 90 miles from the sea
0:07:12 > 0:07:15and you'll often find that salmon will take a break
0:07:15 > 0:07:18and rest up in deep pools just like this one.
0:07:21 > 0:07:23The salmon wait here until the time is right
0:07:23 > 0:07:26for the final leg of their journey.
0:07:30 > 0:07:33I wanted to follow the route the salmon will take
0:07:33 > 0:07:38in a few months' time, when autumn comes and rain swells the Wye.
0:07:38 > 0:07:41That's when they can make their final sprint,
0:07:41 > 0:07:45climbing over 300m into the Welsh mountains.
0:07:48 > 0:07:52It's hard to imagine how they manage to overcome rapids like these.
0:07:52 > 0:07:55They can leap well higher than me.
0:07:55 > 0:07:59What always amazes me is the fact that they have such energy left
0:07:59 > 0:08:01at the end of their long journey.
0:08:01 > 0:08:05They won't have eaten for the entire time they've spent on this river.
0:08:05 > 0:08:08They're doing all this on an empty stomach.
0:08:08 > 0:08:10It's extraordinary what they can achieve
0:08:10 > 0:08:14when you think they're using their very last reserves of energy.
0:08:17 > 0:08:21It's an incredible feat and not all of the salmon make it.
0:08:28 > 0:08:31I'm now in the very upper stretches of the River Wye,
0:08:31 > 0:08:33in one of the many little tributaries
0:08:33 > 0:08:35that feeds into the main channel itself,
0:08:35 > 0:08:39and this is where the salmon come to complete their journey.
0:08:40 > 0:08:45It's here they will spawn the next generation of fantastic swimmers.
0:08:48 > 0:08:51The resulting numbers of baby salmon in the Wye
0:08:51 > 0:08:54are an indication of the health of the river.
0:08:54 > 0:08:58So I'm joining Stephen Marsh-Smith and Haydn Probert
0:08:58 > 0:09:00from the Wye and Usk Foundation.
0:09:00 > 0:09:05They're using the latest technology to catch and count young salmon.
0:09:06 > 0:09:09An electric current briefly stuns the fish
0:09:09 > 0:09:11so they can be caught without harming them.
0:09:14 > 0:09:17Electrocuting fish, it sounds pretty dramatic,
0:09:17 > 0:09:20but they recover very quickly, don't they?
0:09:20 > 0:09:23Yeah, as soon as they're out of the current, the fish will be fine.
0:09:23 > 0:09:25The smaller fish recover a lot quicker.
0:09:25 > 0:09:27Ooh. Is that one?
0:09:28 > 0:09:29- Yeah.- Nice.
0:09:35 > 0:09:36Oh!
0:09:36 > 0:09:38There we go. Ooh, three of them.
0:09:41 > 0:09:43So how old would these guys be?
0:09:43 > 0:09:44Just a couple of months.
0:09:44 > 0:09:47- Is that all?- Yeah.- Wow!
0:09:47 > 0:09:49And so, basically, these surveys are going to tell you
0:09:49 > 0:09:52how the population of young salmon are doing over time,
0:09:52 > 0:09:54and how are they doing?
0:09:54 > 0:09:56Well, rather better than they were when we started,
0:09:56 > 0:09:58I'm very pleased to say.
0:09:58 > 0:09:59And why is that?
0:09:59 > 0:10:02Why are there more here now than there were a few years ago?
0:10:02 > 0:10:05Well, in this part of the river, we've sorted out acid rain,
0:10:05 > 0:10:08or the effects of it, adding limestone sand
0:10:08 > 0:10:11to all the little tributaries that run into it.
0:10:11 > 0:10:13And that's brought back the invertebrate life,
0:10:13 > 0:10:17and it's brought back the fish life, including the salmon.
0:10:17 > 0:10:19So that's the timer.
0:10:19 > 0:10:20Turn that off.
0:10:22 > 0:10:23And see what we've got.
0:10:24 > 0:10:26Not a bad little haul, is it?
0:10:26 > 0:10:27Very nice.
0:10:30 > 0:10:32The team records the survey results.
0:10:33 > 0:10:36And very soon the young fish are free again
0:10:36 > 0:10:39to enjoy the clean waters of the River Wye.
0:10:42 > 0:10:43Nice to see these little guys
0:10:43 > 0:10:45back in the river again where they belong.
0:10:45 > 0:10:47You know, in the next year or two,
0:10:47 > 0:10:49a little switch is going to go off in their brains
0:10:49 > 0:10:53that's going to tell them to swim downstream to the sea.
0:10:53 > 0:10:56But the fact that these animals can get from here
0:10:56 > 0:11:01and all the way down the river and out to Greenland and back again
0:11:01 > 0:11:04is somehow very reassuring that Britain is still wild.
0:11:11 > 0:11:16The journey taken by those little salmon parr really is astonishing.
0:11:16 > 0:11:19It always amazes me how they make their way out of the river
0:11:19 > 0:11:22to the feeding grounds and get back to the river of their birth.
0:11:22 > 0:11:26But at least people are here improving the water quality
0:11:26 > 0:11:28and things are looking good for them,
0:11:28 > 0:11:30and that's important because the River Wye salmon
0:11:30 > 0:11:32are actually a unique population.
0:11:32 > 0:11:37So there are different populations in each river all around the UK?
0:11:37 > 0:11:38Exactly.
0:11:38 > 0:11:42Yeah, and you might think you have to go to really remote places
0:11:42 > 0:11:45in order to see the salmon leaping up waterfalls
0:11:45 > 0:11:46but actually you don't.
0:11:48 > 0:11:49On the River Severn in Shrewsbury,
0:11:49 > 0:11:52the man-made weir is a great place to see them leaping,
0:11:52 > 0:11:55and it's proving to be quite an attraction.
0:11:57 > 0:12:00Salmon are a big draw for wildlife watchers,
0:12:00 > 0:12:04anglers and photographers right here in the UK.
0:12:04 > 0:12:09But they're also the reason for all that activity in Alaska right now.
0:12:09 > 0:12:14The return of the Pacific salmon heralds a real wildlife spectacle
0:12:14 > 0:12:18and, when that happens, you can be assured that wildlife film crews
0:12:18 > 0:12:19are not far behind.
0:12:20 > 0:12:25The salmon also attract large predators like the salmon shark.
0:12:25 > 0:12:29And this was an opportunity for Wild Alaska Live's Steve Backshall
0:12:29 > 0:12:33to get close to a shark he's never seen before.
0:12:33 > 0:12:36But just how did Steve and the team set about their challenge?
0:12:42 > 0:12:45This is going to be home for the next six days or so.
0:12:45 > 0:12:48We're surrounded by the chilly waters of Prince William Sound.
0:12:48 > 0:12:50There's always something going on out here -
0:12:50 > 0:12:52loads of sea otters, seals and sea lions.
0:12:52 > 0:12:55So, yeah, it's a really exciting place to be.
0:12:56 > 0:12:58Steve and the crew are eager to get going
0:12:58 > 0:13:01whilst the weather is on their side.
0:13:01 > 0:13:05So they load the gear into the boat and head out to find the sharks.
0:13:06 > 0:13:10They're looking for a telltale sign of the shark's dorsal fin
0:13:10 > 0:13:12breaking the surface of the water,
0:13:12 > 0:13:15and they need to keep their eyes peeled.
0:13:17 > 0:13:18Wow, look at this! Look at this!
0:13:18 > 0:13:19Amazing!
0:13:19 > 0:13:21Look, it's there. Just right there.
0:13:23 > 0:13:25Just banked away at the last second.
0:13:25 > 0:13:26And it's dived.
0:13:28 > 0:13:30To stand a chance of being in the water with the sharks,
0:13:30 > 0:13:32they need to stick around,
0:13:32 > 0:13:36and shark expert Boone Hodgkin has developed a harmless technique
0:13:36 > 0:13:39to keep the sharks close - by offering them a treat.
0:13:39 > 0:13:41We'll throw some floaters, see if she'll take that,
0:13:41 > 0:13:43and then we'll get you in the water.
0:13:47 > 0:13:50Sadly, this shark isn't interested,
0:13:50 > 0:13:53unlike some of the birdlife around here!
0:13:53 > 0:13:55No action, you know.
0:13:55 > 0:13:57It's what it is. It's hit or miss.
0:13:57 > 0:13:59So we've got to find a player.
0:14:00 > 0:14:03The crew head along the coast,
0:14:03 > 0:14:07and it's not long before they find another shark.
0:14:07 > 0:14:10Check that out!
0:14:10 > 0:14:11That is amazing.
0:14:13 > 0:14:15And the plan is put into action again.
0:14:15 > 0:14:16Come on, girl.
0:14:16 > 0:14:18You've got to aim it just right.
0:14:20 > 0:14:22Cos you want it to sink right in front of her.
0:14:22 > 0:14:24Yeah, she's coming round, look.
0:14:24 > 0:14:26She's about to broadside right alongside us.
0:14:27 > 0:14:29Look at that dorsal fin.
0:14:29 > 0:14:31Let's see if she takes it.
0:14:31 > 0:14:34Go on.
0:14:34 > 0:14:36But, once again, there are no takers.
0:14:36 > 0:14:38And, as the weather turns,
0:14:38 > 0:14:41the crew have no choice but to head back to base.
0:14:41 > 0:14:45I don't think I've ever tried to film an animal where the conditions
0:14:45 > 0:14:49have to be so precise and so perfect as they do here.
0:14:49 > 0:14:52We were out for maybe, I guess, six or seven hours this morning
0:14:52 > 0:14:55and then the wind got up just a tiny little bit,
0:14:55 > 0:14:57and that was too much for us to see any shark fins
0:14:57 > 0:15:01and we've been basically sat around waiting for the last seven hours.
0:15:01 > 0:15:05It's now eight o'clock at night and we're just going back out again.
0:15:05 > 0:15:07And who knows what will happen?
0:15:07 > 0:15:12But, for now, it's mirror-flat, calm, perfect.
0:15:14 > 0:15:15Fingers crossed.
0:15:17 > 0:15:19With the weather back on their side,
0:15:19 > 0:15:23it's not long before the crew have another shark in their sights.
0:15:23 > 0:15:28And it's time for cameraman Mark, and Steve, to get in amongst them.
0:15:28 > 0:15:30But, despite appearances from above the surface,
0:15:30 > 0:15:33the underwater team are facing a real problem.
0:15:34 > 0:15:38They just can't get close enough to see the shark through the gloom.
0:15:41 > 0:15:43Seriously?
0:15:43 > 0:15:45I could see her dorsal fin on the surface.
0:15:45 > 0:15:46She can't have been more than...
0:15:46 > 0:15:49a metre and a half away from me.
0:15:49 > 0:15:53But I still couldn't film her. Still didn't see her on camera.
0:15:53 > 0:15:54Amazing.
0:15:55 > 0:15:57Back at camp, director Charlie Bingham
0:15:57 > 0:16:00reviews the underwater footage.
0:16:00 > 0:16:03It's really frustrating because the sharks are there.
0:16:03 > 0:16:04We're seeing them topside,
0:16:04 > 0:16:06we're seeing them cutting through the surface
0:16:06 > 0:16:07which is really exciting,
0:16:07 > 0:16:10and Steve's been getting really excited about getting in the water,
0:16:10 > 0:16:12but the visibility is terrible.
0:16:12 > 0:16:14I think we're just going to have to rethink it.
0:16:14 > 0:16:16The visibility's not going to change in the next day or two.
0:16:16 > 0:16:19But, because they're so close to the surface
0:16:19 > 0:16:21and actually breaking the surface,
0:16:21 > 0:16:23I'm wondering whether our best chance
0:16:23 > 0:16:25might actually be to get shots from the top.
0:16:25 > 0:16:27We do have a drone crew with us.
0:16:27 > 0:16:29So I think that's probably our best bet.
0:16:31 > 0:16:33And, as the drone is deployed the next day,
0:16:33 > 0:16:37it becomes apparent that Charlie's hunch was spot on,
0:16:37 > 0:16:40and the team finally capture the remarkable images they were after.
0:16:42 > 0:16:45The crew may have been thwarted in their underwater quest,
0:16:45 > 0:16:46but from up high,
0:16:46 > 0:16:50the beauty of this special Alaskan predator is revealed.
0:17:03 > 0:17:04It just goes to show, doesn't it,
0:17:04 > 0:17:07that not everything in wildlife film-making goes according to plan?
0:17:07 > 0:17:08It rarely does.
0:17:08 > 0:17:11No, no, and he got so close, didn't he?
0:17:11 > 0:17:13But he just couldn't see that shark underwater.
0:17:13 > 0:17:16Well, we've got more from the Wild Alaska Live team
0:17:16 > 0:17:19this Wednesday at 8pm and, of course,
0:17:19 > 0:17:20you can catch up with what they're doing
0:17:20 > 0:17:24all this week online and via social media.
0:17:24 > 0:17:28Now, those Pacific salmon that the sharks were feeding on,
0:17:28 > 0:17:32and our own Atlantic salmon, travel vast distances
0:17:32 > 0:17:34back to the rivers of their birth.
0:17:34 > 0:17:37But they're not the only long-distance migrants
0:17:37 > 0:17:41that travel a long way back to the UK every year.
0:17:41 > 0:17:44And, in 2014, the One Show's Mike Dilger
0:17:44 > 0:17:48went to the Norfolk Broads for an unusual encounter
0:17:48 > 0:17:51with a very familiar long-distance migrant.
0:17:54 > 0:17:57MIKE: The Norfolk broads are one of the UK's most important wetlands
0:17:57 > 0:18:00and are the setting of some of the boating adventures
0:18:00 > 0:18:03in the Swallows and Amazons books by Arthur Ransome.
0:18:03 > 0:18:06But, 80 years after those books were published,
0:18:06 > 0:18:08I've come here to find some real-life swallows
0:18:08 > 0:18:11that have been doing a little boating of their own.
0:18:13 > 0:18:17Ross Warrell has owned the Lady Ann, a traditional wooden Broads boat,
0:18:17 > 0:18:18for nearly ten years.
0:18:18 > 0:18:20It's used as a tour boat,
0:18:20 > 0:18:24taking visitors to spot wildlife in these magical waterways.
0:18:24 > 0:18:26But for the last couple of summers,
0:18:26 > 0:18:29people haven't just been watching wildlife from the boat,
0:18:29 > 0:18:31they've been watching wildlife ON the boat.
0:18:32 > 0:18:36A family of swallows have taken up residence on board.
0:18:36 > 0:18:38Just put your head around the corner here,
0:18:38 > 0:18:41and if you look through this little gap here, you'll see the nest.
0:18:41 > 0:18:45There's a mud nest just stuck to the wall here
0:18:45 > 0:18:47and I can see beaks poking out.
0:18:47 > 0:18:50- Can I have a look around the side? - Help yourself.
0:18:50 > 0:18:52Oh, that is fabulous.
0:18:52 > 0:18:54One, two, three chicks.
0:18:54 > 0:18:57I can see all their bills. That is remarkable.
0:18:57 > 0:18:58Fantastic, isn't it?
0:18:58 > 0:19:01I worried like anything about having them actually nesting on board
0:19:01 > 0:19:04and thought, "This is not a very wise place for them to be."
0:19:04 > 0:19:06As it turns out, they knew best.
0:19:06 > 0:19:07Last year, we had two broods
0:19:07 > 0:19:10successfully raised from that very nest.
0:19:10 > 0:19:14And this pair of swallows came along about the third week in May.
0:19:14 > 0:19:16- CHICKS CALL - Oh, they're feeding.
0:19:16 > 0:19:18I just heard the little buzz-buzz-buzz,
0:19:18 > 0:19:20which means one of the adults must have whizzed straight in.
0:19:20 > 0:19:23- "Feed me, feed me!" - And the lucky one gets it.
0:19:23 > 0:19:26A swallow uses its tail as a rudder,
0:19:26 > 0:19:28moving it up, down and side to side to allow the bird
0:19:28 > 0:19:31to make precision movements in the air.
0:19:31 > 0:19:33It's fantastic, isn't it?
0:19:33 > 0:19:37You might think having nesting birds on board would be bad for business
0:19:37 > 0:19:40and the Lady Ann would have to be moored until the chicks are fledged,
0:19:40 > 0:19:43but these parents go where the nest goes.
0:19:44 > 0:19:45Swallows are fast flyers,
0:19:45 > 0:19:51capable of flapping their wings 14 times a second in bursts of speed.
0:19:51 > 0:19:54- There they are, just passed the boat there.- Oh, lovely, look at that.
0:19:54 > 0:19:58Ross, here we are 400m or 500m away from where you moored the boat,
0:19:58 > 0:20:00and the birds are whizzing round, feeding
0:20:00 > 0:20:02and just popping straight into the nest.
0:20:02 > 0:20:04I've never seen it. It's amazing.
0:20:04 > 0:20:07Their streamlined body shape and wings
0:20:07 > 0:20:10make them very efficient flying machines.
0:20:10 > 0:20:12When you think about it, it's perfect habitat.
0:20:12 > 0:20:15All manner of aquatic insects are emerging -
0:20:15 > 0:20:17mayflies, damselflies, stoneflies.
0:20:17 > 0:20:19A swallow chick's weight will increase tenfold
0:20:19 > 0:20:21in the first ten days of its life.
0:20:21 > 0:20:26The parents will catch around 6,000 insects -
0:20:26 > 0:20:30hoovering them out of the sky to feed their chicks - in just one day.
0:20:30 > 0:20:32Keeping track of the boat is quite a feat
0:20:32 > 0:20:35but then these birds are built to travel.
0:20:35 > 0:20:38This is a species that has fabulous eyesight,
0:20:38 > 0:20:42uses visual markers to go all the way from southern Africa to the UK,
0:20:42 > 0:20:45so I suppose finding your boat in the Mere is no problem.
0:20:45 > 0:20:47No, you think at first, how do they find you?
0:20:47 > 0:20:50How do they put up with this moving target?
0:20:50 > 0:20:52Well, yeah, as you said, they come from Africa,
0:20:52 > 0:20:54they manage that quite well without someone holding their hand,
0:20:54 > 0:20:56they're quite capable of finding me -
0:20:56 > 0:20:58whether I'm here, a mile that way, a mile the other way.
0:20:58 > 0:21:00They're cool with it.
0:21:00 > 0:21:03Absolutely wonderful. Here they come.
0:21:05 > 0:21:08LAUGHING: Look at that! Straight in.
0:21:10 > 0:21:12It's a mobile home, they're not bothered.
0:21:12 > 0:21:15And the swallows do benefit from life on a houseboat.
0:21:15 > 0:21:19They're constantly working different areas and resources
0:21:19 > 0:21:21- that are full of insects.- Precisely.
0:21:21 > 0:21:22And you are a protector as well.
0:21:22 > 0:21:26I am a protector - any predators come anywhere near this boat,
0:21:26 > 0:21:28during the daytime when I'm operating,
0:21:28 > 0:21:30Uncle Ross will sort them out.
0:21:30 > 0:21:31MIKE LAUGHS
0:21:31 > 0:21:35Ross's little hitchhikers are a hit with the tourists too.
0:21:35 > 0:21:38These are wildlife tours with a twist.
0:21:39 > 0:21:42I've seen some birds nesting in wacky places,
0:21:42 > 0:21:45but this location has to take the biscuit.
0:21:45 > 0:21:48I think they should change the name of this boat from the Lady Ann
0:21:48 > 0:21:50to the Swallow of the Norfolk Broads.
0:21:55 > 0:22:00Those swallows came back to Rob's boat every year until 2016.
0:22:00 > 0:22:02But, sadly, not this year.
0:22:02 > 0:22:06Now, of course, the Norfolk Broads are a really important wetland area
0:22:06 > 0:22:09and they're big - 300 square kilometres
0:22:09 > 0:22:13of interconnected waterways and lakes that are known as Broads.
0:22:13 > 0:22:17They may look natural but the Broads are actually flooded peat workings
0:22:17 > 0:22:19dug in the Middle Ages to provide fuel
0:22:19 > 0:22:23for the nearby towns of Norwich and Great Yarmouth.
0:22:23 > 0:22:25Now, of course, the landscape of the Norfolk Broads
0:22:25 > 0:22:29was once very different, as it was all across the UK,
0:22:29 > 0:22:33and was home to very different animals as a result.
0:22:33 > 0:22:36Now, some of those long-lost beasts are actually making a return,
0:22:36 > 0:22:39- aren't they, Colin? - They are, and one of the animals
0:22:39 > 0:22:44that was once found right across the UK in rivers just like this one
0:22:44 > 0:22:46was the European beaver.
0:22:46 > 0:22:49But sadly, by the 16th century, they'd become extinct.
0:22:50 > 0:22:55A trial reintroduction programme has been running in Scotland since 2009
0:22:55 > 0:22:59but reports of beaver living wild on the River Otter in Devon
0:22:59 > 0:23:01date back to 2007.
0:23:01 > 0:23:04Nobody knows where these beavers came from,
0:23:04 > 0:23:07but if there was any chance for them to be allowed staying in the wild,
0:23:07 > 0:23:12the Devon Wildlife Trust had to find out more about them.
0:23:12 > 0:23:13In 2015,
0:23:13 > 0:23:15the beavers were captured from the wild
0:23:15 > 0:23:18and brought to a makeshift veterinary centre
0:23:18 > 0:23:20where experts conducted health checks.
0:23:20 > 0:23:23There are actually two species of beaver -
0:23:23 > 0:23:26the European beaver, once native to the UK,
0:23:26 > 0:23:27and the North American beaver -
0:23:27 > 0:23:30and on the surface, they look identical.
0:23:30 > 0:23:32For the Devon beavers to remain living in the wild,
0:23:32 > 0:23:36the Wildlife Trust had to first prove they were both disease-free
0:23:36 > 0:23:39and pure European beavers.
0:23:39 > 0:23:41The results were positive and so the trust
0:23:41 > 0:23:45were able to re-release the animals back on to the River Otter,
0:23:45 > 0:23:47close to where they were originally captured.
0:23:48 > 0:23:50After the beavers had been released,
0:23:50 > 0:23:53Martin Hughes-Games from Springwatch travelled to the River Otter
0:23:53 > 0:23:57to find out just what kind of an impact the release of these animals
0:23:57 > 0:23:59can have on our wild spaces.
0:24:03 > 0:24:06- MARTIN:- 'Beavers were once native to Britain.
0:24:06 > 0:24:08'But their return now is controversial,
0:24:08 > 0:24:11'because of their ability to dramatically alter the landscape
0:24:11 > 0:24:13'by building dams and lodges.
0:24:15 > 0:24:18'Because they've been absent from England for so long,
0:24:18 > 0:24:20'no-one knows what their return will involve
0:24:20 > 0:24:23'or how much effect they will have on the landscape
0:24:23 > 0:24:25'in and around our river systems.
0:24:26 > 0:24:31'So, in 2011, the Devon Beaver Project was set up
0:24:31 > 0:24:33'to assess their impact.'
0:24:33 > 0:24:35Everywhere you look there are...
0:24:35 > 0:24:39'Mark Elliott is a project manager and he showed me round.'
0:24:39 > 0:24:42So, Mark, what was it like before the beavers came?
0:24:42 > 0:24:44Well, it was an awful lot drier.
0:24:44 > 0:24:46There was just this little tiny stream running through the site -
0:24:46 > 0:24:49you can just about make out the old channel there.
0:24:49 > 0:24:51- What, this is the actual channel here?- Yeah, that was it.
0:24:51 > 0:24:54But there was no other standing water on the site at all.
0:24:54 > 0:24:57So all of the open water that we see here now
0:24:57 > 0:24:59is all generated by the beavers.
0:24:59 > 0:25:01- MARTIN LAUGHS Like this.- Um...
0:25:01 > 0:25:03That's a bit of a transformation, isn't it?
0:25:03 > 0:25:07There's about 250 square metres of water
0:25:07 > 0:25:08in some of these biggest ponds.
0:25:08 > 0:25:10I mean, you can see the level of the dam now -
0:25:10 > 0:25:12it's about a metre and a half, two metres high.
0:25:12 > 0:25:15How many beavers does it take to do this? Dozens, presumably.
0:25:15 > 0:25:17We've only got four in here at the moment.
0:25:17 > 0:25:19- FOUR beavers did THIS?!- Yeah.
0:25:20 > 0:25:23It's all infilled with mud, presumably.
0:25:23 > 0:25:25It's almost the mud that they start off with,
0:25:25 > 0:25:27and then they add additional sticks for support.
0:25:27 > 0:25:29So they're dredging the mud from the pond.
0:25:29 > 0:25:31You see them surging forward,
0:25:31 > 0:25:33push this mud up on to the top of the dam
0:25:33 > 0:25:37and then they'll add sticks to that. I mean, it's remarkable, really -
0:25:37 > 0:25:40we've got now about 600 cubic metres of water
0:25:40 > 0:25:42standing in these ponds on the site.
0:25:42 > 0:25:45So once they'd got their teeth in, there was no stopping them.
0:25:45 > 0:25:47No, that's right, they really went for it.
0:25:48 > 0:25:51One potential benefit of the creation of these pools
0:25:51 > 0:25:55is that heavy rainfall is retained and released slowly,
0:25:55 > 0:25:57helping to reduce flooding further downstream.
0:25:59 > 0:26:01We're seeing all sorts of impacts here.
0:26:01 > 0:26:03They are not called a keystone species for nothing.
0:26:03 > 0:26:06- Come and have a look at this. - Ooh! Tantalising.
0:26:06 > 0:26:08'Some of the changes were expected,
0:26:08 > 0:26:12'but one in particular was dramatic and surprising.'
0:26:13 > 0:26:16So one of the things that's done really well is common frogs.
0:26:16 > 0:26:18This is a huge area of frogspawn here, look.
0:26:18 > 0:26:19Is it?
0:26:19 > 0:26:21Oh, look at that, they've all hatched out.
0:26:21 > 0:26:22- They've all just hatched.- Wow!
0:26:22 > 0:26:25So there's thousands and thousands of them here.
0:26:25 > 0:26:28When you get your eye in, they're everywhere, aren't they?
0:26:28 > 0:26:30- This is all one big area of them. - It's black with them.
0:26:30 > 0:26:34We counted 521 clumps across the site this year.
0:26:34 > 0:26:36And that compares to only ten in the first year,
0:26:36 > 0:26:38- when we put the beavers in. - Ten?!- Yeah.
0:26:38 > 0:26:40There was nowhere for them to breed -
0:26:40 > 0:26:41there was just no standing water at all.
0:26:41 > 0:26:43So since the beavers have come,
0:26:43 > 0:26:45they've created all of these amazing ponds
0:26:45 > 0:26:47and the frogs are just absolutely loving it,
0:26:47 > 0:26:49so numbers have just come up and up and up.
0:26:49 > 0:26:52I suppose tadpoles, frogs - bottom of the food chain -
0:26:52 > 0:26:54other wildlife will be benefiting from this?
0:26:54 > 0:26:56Absolutely. Things like herons,
0:26:56 > 0:26:57we're seeing a lot of herons here now
0:26:57 > 0:26:59cos they're feeding on the frogs.
0:26:59 > 0:27:02Grass snakes - you'd expect to see an increase in grass snakes
0:27:02 > 0:27:04because again, they're feeding on the frogs.
0:27:04 > 0:27:07They're just a really important part of the food chain.
0:27:07 > 0:27:11It seems to me, though, that everything seems to be positive.
0:27:11 > 0:27:15Everything seems to be benefiting from what the beavers are doing.
0:27:15 > 0:27:16Are there any downsides?
0:27:16 > 0:27:19Well, I think there's always going to be a mixed picture -
0:27:19 > 0:27:21there's going to be some things that benefit
0:27:21 > 0:27:22and some that don't do quite so well.
0:27:22 > 0:27:25One of the concerns that's raised by salmon fishermen particularly
0:27:25 > 0:27:27is about fish migration.
0:27:27 > 0:27:29They struggle to get up over the dams
0:27:29 > 0:27:31into the headwaters where they breed.
0:27:31 > 0:27:33And that's what does happen in some cases -
0:27:33 > 0:27:35if you've got a series of dams in the way
0:27:35 > 0:27:37as the salmon migrate upstream to their spawning gravels,
0:27:37 > 0:27:41then those dams prevent access to the upper tributaries.
0:27:41 > 0:27:44But those impacts will vary a lot between catchment to catchment.
0:27:46 > 0:27:51Although not everyone welcomes a return of these keystone engineers,
0:27:51 > 0:27:53they're now living wild on the River Otter,
0:27:53 > 0:27:56at least for a trial period.
0:27:56 > 0:27:58But it will take several years of monitoring
0:27:58 > 0:28:02before the full impact of their return to English waterways
0:28:02 > 0:28:03is fully understood.
0:28:07 > 0:28:08You always have to be careful
0:28:08 > 0:28:11with any of these animal re-introductions.
0:28:11 > 0:28:15But I, for one, think it is just great that one day,
0:28:15 > 0:28:17both the beaver and the habitats that they create
0:28:17 > 0:28:22could once again be a common sight across the UK countryside.
0:28:22 > 0:28:23Yeah, it's interesting, isn't it,
0:28:23 > 0:28:27that a lot of these animals that are being considered for re-wilding
0:28:27 > 0:28:31here in the UK are actually species that you find in Alaska,
0:28:31 > 0:28:35which just goes to show, we're not as different as you might think.
0:28:35 > 0:28:37The UK was once home to not only beaver
0:28:37 > 0:28:42but also the lynx, the wolf and even the Eurasian brown bear.
0:28:42 > 0:28:46Now, of course, reintroducing any animal back into the wild
0:28:46 > 0:28:48is a seriously complicated business
0:28:48 > 0:28:51but we've had some huge successes here in the UK, haven't we?
0:28:51 > 0:28:54- We sure have.- And we're going to be bringing you one of those stories,
0:28:54 > 0:28:57that of the sea eagle, later this week.
0:28:57 > 0:29:00But we don't just want to show you the UK's wildlife and wild places
0:29:00 > 0:29:02in the comfort of your own living room -
0:29:02 > 0:29:06we are really hoping that we can encourage you to get out
0:29:06 > 0:29:08and immerse yourself in nature,
0:29:08 > 0:29:11and maybe have your very own wild river experience.
0:29:11 > 0:29:12Now, many of you already do,
0:29:12 > 0:29:15but if you need a little bit of extra inspiration,
0:29:15 > 0:29:18then here's our guide to where the wild things are.
0:29:21 > 0:29:23Wherever you are in the UK,
0:29:23 > 0:29:26there will be a river not too far away,
0:29:26 > 0:29:28a place for you to escape into the wild.
0:29:30 > 0:29:34If waterfalls are your thing, head for the hills year-round.
0:29:34 > 0:29:37Raging autumn torrents where salmon leap
0:29:37 > 0:29:40or gentle trickling streams in summer.
0:29:43 > 0:29:45In Wales, the Four Waterfalls Walk
0:29:45 > 0:29:47in the Brecon Beacons is a favourite.
0:29:53 > 0:29:56Dippers are a classic river bird.
0:29:56 > 0:30:00Found along fast-flowing streams, they hunt for invertebrates
0:30:00 > 0:30:03and nest under bridges in many of our rivers.
0:30:03 > 0:30:06They can be spotted across much of the UK
0:30:06 > 0:30:08but mainly in the west and north.
0:30:08 > 0:30:11A great place to see both adults and fledglings
0:30:11 > 0:30:14is the Peak District National Park in summer.
0:30:16 > 0:30:20If it's mammals you're after, then the water vole is one of the cutest.
0:30:20 > 0:30:24These semiaquatic rodents consume an incredible 80% of their body weight
0:30:24 > 0:30:28each day, so need densely-vegetated river banks.
0:30:28 > 0:30:32Special places to try and spot them include the wetlands at Magor Marsh
0:30:32 > 0:30:35in Gwent, and the millponds of Cheddar Gorge in Somerset.
0:30:36 > 0:30:38If you want to see a river otter,
0:30:38 > 0:30:41the best plan is to head out at dawn or dusk.
0:30:41 > 0:30:45These elusive animals are most common in Wales, south-west England,
0:30:45 > 0:30:47Scotland and Northern Ireland.
0:30:54 > 0:30:58Rivers have played a vital role in the development of many nations
0:30:58 > 0:31:01and almost all of the world's capital cities
0:31:01 > 0:31:04have a significant river flowing through them.
0:31:04 > 0:31:09In the 16th and 17th centuries, as industry began to expand,
0:31:09 > 0:31:12waterways were seen as the most reliable way
0:31:12 > 0:31:15of moving around raw materials,
0:31:15 > 0:31:19and big rivers like the Thames had navigation improvements.
0:31:19 > 0:31:23The onset of the Industrial Revolution in the mid 18th century
0:31:23 > 0:31:27saw the construction of a vast network of canals.
0:31:27 > 0:31:29And it may not have been the original intention,
0:31:29 > 0:31:35but these man-made rivers have now become valuable wild spaces.
0:31:35 > 0:31:37As Lucy discovered when she headed
0:31:37 > 0:31:39to the old industrial heart of England.
0:31:43 > 0:31:45This leafy green by water
0:31:45 > 0:31:47is the Staffordshire and Worcestershire Canal,
0:31:47 > 0:31:48just west of Birmingham.
0:31:50 > 0:31:54Chugging along slowly on a barge is a great way to appreciate it.
0:31:54 > 0:31:57When this canal was built in 1771,
0:31:57 > 0:32:00it joined the Staffordshire Potteries to Stourport
0:32:00 > 0:32:01and then to Bristol,
0:32:01 > 0:32:05and it also connected the Black Country to Liverpool.
0:32:05 > 0:32:08In those days, it was the beginning of the Industrial Revolution,
0:32:08 > 0:32:12and this waterway would have been busy with barges
0:32:12 > 0:32:15carrying coal and iron back and forth.
0:32:15 > 0:32:16Since 1978,
0:32:16 > 0:32:20this has been a conservation area and it now provides over 47 miles -
0:32:20 > 0:32:2375km - of habitat.
0:32:23 > 0:32:25Hello, Paul.
0:32:25 > 0:32:29'Paul Wilkinson is an ecologist who is dedicated to making the canals
0:32:29 > 0:32:31'of the West Midlands a haven for wildlife.
0:32:33 > 0:32:35'Thanks to Paul, an army of volunteers
0:32:35 > 0:32:39'and some natural ingenuity, wildlife like kingfishers,
0:32:39 > 0:32:43'water voles and even otters have returned in numbers.'
0:32:44 > 0:32:47We're just coming up to the artificial kingfisher nesting site
0:32:47 > 0:32:50just on this corner. They've put the little perch in,
0:32:50 > 0:32:51it's actually been in eight years now.
0:32:51 > 0:32:53It's suffered a little bit.
0:32:53 > 0:32:55That's a beautiful spot, isn't it?
0:32:55 > 0:32:57If I was a kingfisher,
0:32:57 > 0:32:59I'd definitely be hanging out on that perch.
0:32:59 > 0:33:02It's a complete contrast to how it would have been.
0:33:02 > 0:33:06This would have been industrial, hard place, no space for wildlife.
0:33:06 > 0:33:08This is the original re-wilding package.
0:33:08 > 0:33:11The Trust do a lot of maintenance and monitoring on the canals
0:33:11 > 0:33:13and Paul is putting me to work,
0:33:13 > 0:33:15taking samples of the local water life.
0:33:17 > 0:33:20This is the bottom of the food chain in a way, isn't it?
0:33:20 > 0:33:21What supports all the kingfishers
0:33:21 > 0:33:24and the otters and the showy animals
0:33:24 > 0:33:27is these creepy crawlies in the water.
0:33:28 > 0:33:30There's a kingfisher.
0:33:30 > 0:33:34Oh! How fantastic!
0:33:34 > 0:33:36I LOVE kingfishers.
0:33:36 > 0:33:39I cannot believe we've been that lucky.
0:33:39 > 0:33:40Beautiful.
0:33:43 > 0:33:47Of all the animals that benefit from healthy canals and rivers,
0:33:47 > 0:33:49Paul's most proud of the work that's been done
0:33:49 > 0:33:53to encourage and grow the bat population.
0:33:53 > 0:33:57The installation of dozens of bat boxes along the banks of the canal
0:33:57 > 0:33:59has been a big success.
0:33:59 > 0:34:03And Paul's taking me along one of his regular monitoring projects.
0:34:03 > 0:34:07If I'm lucky, Paul's special licence to handle bats
0:34:07 > 0:34:09may give me a close-up encounter.
0:34:17 > 0:34:18Yeah, we've got a bat.
0:34:18 > 0:34:20Yes! Fantastic.
0:34:20 > 0:34:22What a score.
0:34:22 > 0:34:25Wow, look at that.
0:34:25 > 0:34:27This is a soprano pipistrelle.
0:34:27 > 0:34:30When they flutter around you, because of the wings being out,
0:34:30 > 0:34:33you get this idea that they're much bigger than they are.
0:34:33 > 0:34:35The soprano pipistrelle's by far the commonest bat we get
0:34:35 > 0:34:38along the waterways in our bat boxes.
0:34:38 > 0:34:42So these are actually indicators of good woodlands, good water quality.
0:34:42 > 0:34:43Because of their diet,
0:34:43 > 0:34:47they need the amount of insects and aquatic insects in particular.
0:34:47 > 0:34:49It takes so much energy to fly
0:34:49 > 0:34:52and it takes so much energy for a little body to get warm,
0:34:52 > 0:34:54they need lots of good-quality food.
0:34:56 > 0:34:59And that food is found in great abundance around here.
0:35:00 > 0:35:03So to witness just what an excellent location
0:35:03 > 0:35:07this canal has now become for bats, Paul's brought me back after dark -
0:35:07 > 0:35:09when the bats take to the wing.
0:35:09 > 0:35:12We've brought bat detectors to tune into their wavelengths.
0:35:12 > 0:35:14DETECTORS EMIT CHIRPS
0:35:14 > 0:35:19Bats make a high-frequency sound, and this is converting that sound
0:35:19 > 0:35:22into a lower frequency so that we can actually hear it.
0:35:22 > 0:35:24Yeah, their calls are much higher than we can hear.
0:35:24 > 0:35:26This is an entrance into a secret world, isn't it, really?
0:35:26 > 0:35:28Well, if you turn them off...
0:35:28 > 0:35:30CHIRPS REDUCE TO SILENCE
0:35:33 > 0:35:35..who would know there were bats here?
0:35:35 > 0:35:39- You'd never know, would you? You would never know.- No.
0:35:39 > 0:35:42- And suddenly, they're revealed. - Mm-hm.
0:35:42 > 0:35:44DETECTORS EMIT CHIRPS
0:35:48 > 0:35:51So why are canals a particularly good area for bats?
0:35:51 > 0:35:52You've got the water,
0:35:52 > 0:35:56so straight away you've got the insects emerging from the water,
0:35:56 > 0:36:00but also you've got the drinking so especially females, every night,
0:36:00 > 0:36:02their first call is to have a drink of water.
0:36:02 > 0:36:05And it's nice and calm water rather than fast, rushing streams
0:36:05 > 0:36:07which can often catch them out.
0:36:07 > 0:36:08And more importantly,
0:36:08 > 0:36:12there's hardly any light pollution whatsoever on a canal like this.
0:36:17 > 0:36:20Some people find them scary.
0:36:20 > 0:36:21The fact is, they're fascinating,
0:36:21 > 0:36:23there's so much we can learn from them.
0:36:23 > 0:36:27The more and more we start to study them, we make them less cryptic.
0:36:29 > 0:36:32You've got to love any animal that eat midges and mosquitoes,
0:36:32 > 0:36:35- haven't you?- Exactly. And in large numbers.
0:36:35 > 0:36:39They're out there every night consuming harmful insects
0:36:39 > 0:36:41and they don't want a salary.
0:36:41 > 0:36:42SHE LAUGHS
0:36:46 > 0:36:49A lot of people don't really like bats but it's worth knowing
0:36:49 > 0:36:55that each one of those pipistrelles can hoover up 3,000 flying insects
0:36:55 > 0:36:56in a single night.
0:36:56 > 0:36:59And as someone who's just been savaged by midges here in Scotland
0:36:59 > 0:37:03for the last few days, I say bring on the pipistrelles - we love you!
0:37:03 > 0:37:05I couldn't agree with you more, Lucy.
0:37:05 > 0:37:08They are a bit of a disaster around here sometimes.
0:37:08 > 0:37:11But you know, we've got 18 different species of bats in the UK
0:37:11 > 0:37:15and the biggest one, the noctule, could fit in the palm of my hand.
0:37:15 > 0:37:17They feed only on insects
0:37:17 > 0:37:20and many of them emerge from the water itself.
0:37:21 > 0:37:24Using state-of-the-art thermal imaging cameras,
0:37:24 > 0:37:29teams from the BBC Natural History unit were able to capture
0:37:29 > 0:37:33this amazing scene of a variety of different bat species
0:37:33 > 0:37:37all feeding on emerging insects over a lake in late spring.
0:37:38 > 0:37:41Now, all of these insects, of course, are a great indicator
0:37:41 > 0:37:44of the cleanliness of our water which, when healthy,
0:37:44 > 0:37:48can support a really surprising variety of life.
0:37:48 > 0:37:52And there's a very strange creature that lurks in our rivers
0:37:52 > 0:37:55that few of us may ever have seen or heard of.
0:37:55 > 0:37:59And, in 2015, The One Show's Miranda Krestovnikoff
0:37:59 > 0:38:00went in search of them.
0:38:03 > 0:38:05- MIRANDA:- Morning on the River Frome.
0:38:05 > 0:38:08Who would guess that under these quiet waters
0:38:08 > 0:38:11lurks a beast from prehistoric times?
0:38:11 > 0:38:15Imagine turning the clock back 400 million years
0:38:15 > 0:38:19to a time before woolly mammoths, even before the dinosaurs.
0:38:19 > 0:38:22It's hard to believe a creature that lived then
0:38:22 > 0:38:25still exists here in the UK today.
0:38:25 > 0:38:27I'm in Dorset to find one of the oldest,
0:38:27 > 0:38:30rarest and, frankly, scariest animals in Britain.
0:38:32 > 0:38:36My guide is Bournemouth University fishery scientist Adrian Pinder
0:38:36 > 0:38:39who's promised me a close encounter with an ancient alien -
0:38:39 > 0:38:41the sea lamprey.
0:38:41 > 0:38:44So we're looking for sea lampreys but yet we're looking for them
0:38:44 > 0:38:47in a freshwater river habitat - how exactly does that work?
0:38:47 > 0:38:51Well, sea lampreys spawn in fresh water and then spend a portion
0:38:51 > 0:38:53of their adult life at sea before coming back up the river
0:38:53 > 0:38:55to spawn again.
0:38:55 > 0:38:59At sea, sea lamprey are truly gruesome parasites
0:38:59 > 0:39:02that attach themselves by their sucker mouths to fish
0:39:02 > 0:39:06and grind away the flesh of their host.
0:39:06 > 0:39:08By contrast, on their return to fresh water,
0:39:08 > 0:39:11those mouth parts are used to construct their nests.
0:39:13 > 0:39:15If we take a look at the gravel in front of us down here,
0:39:15 > 0:39:18you can see there's a thin layer of algae all over it.
0:39:18 > 0:39:19When the adult lamprey come upstream,
0:39:19 > 0:39:21what they do is they start moving stones around
0:39:21 > 0:39:24- so they're turning them over to create their nests.- OK.
0:39:24 > 0:39:27So we're looking for big patches of clean gravel, really.
0:39:27 > 0:39:31Sea lamprey swim into UK rivers to breed, where they need shallow,
0:39:31 > 0:39:35fast-flowing waters to reach at least 15 degrees centigrade
0:39:35 > 0:39:36in order to spawn.
0:39:36 > 0:39:39So, with a bit of luck, I'm hoping to see them in action.
0:39:39 > 0:39:42There's a couple of patches up there that look a bit cleaner.
0:39:42 > 0:39:44You've just found your first sea lamprey nest.
0:39:44 > 0:39:48- Fantastic.- I suggest we get kitted up and go and take a closer look.
0:39:48 > 0:39:50OK, amazing.
0:39:50 > 0:39:56Male sea lamprey exude pheromones into the water to attract females.
0:39:56 > 0:40:00Then, together, they prepare nests in the gravel for spawning.
0:40:00 > 0:40:01In order to see this behaviour,
0:40:01 > 0:40:04I've brought along this specially adapted box with a Perspex bottom
0:40:04 > 0:40:06and if I put this on the water,
0:40:06 > 0:40:09I should be able to see through the reflections.
0:40:09 > 0:40:11We're not going to disturb them, are we?
0:40:11 > 0:40:14Well, these fish have only got one thing on their mind at the moment.
0:40:14 > 0:40:15They're going to die after this,
0:40:15 > 0:40:19so they're investing all their energy now into reproduction.
0:40:19 > 0:40:22Oh! I can see it, I can see it, it's there.
0:40:22 > 0:40:23That is incredible.
0:40:25 > 0:40:26Let's take a closer look.
0:40:29 > 0:40:33That's just amazing, they're enormous.
0:40:33 > 0:40:35And they are moving the stones!
0:40:35 > 0:40:38- They've got hold of a stone! - Absolutely.
0:40:38 > 0:40:40- That's incredible. - That's how they construct the nest -
0:40:40 > 0:40:43they're using their sucker disc to actually pick up these stones
0:40:43 > 0:40:45and reposition them around this nest to create a crater
0:40:45 > 0:40:48and, in doing so, that exposes some finer sediment
0:40:48 > 0:40:51in the middle of the pit where they can then lay their eggs.
0:40:51 > 0:40:53They will typically leave a big stone
0:40:53 > 0:40:55in the middle of the nest that they use that as an anchor stone.
0:40:55 > 0:40:58The stone just needs to be sufficiently heavy
0:40:58 > 0:41:00so when they attach to one another and spawn,
0:41:00 > 0:41:04this flow doesn't displace them and wash them out of the nest.
0:41:04 > 0:41:05This one's spawning now.
0:41:05 > 0:41:07Oh, my God. Look at that!
0:41:08 > 0:41:12Oh, my word, so there was a rapid tail wiggle.
0:41:12 > 0:41:14And the male will have wrapped his tail
0:41:14 > 0:41:16around the back end of the female there.
0:41:16 > 0:41:20She'll have drilled into the sediment and deposited the eggs
0:41:20 > 0:41:22just sub-surface of that gravel.
0:41:22 > 0:41:25- Wow.- We should see a coiling event now. Look at this.
0:41:25 > 0:41:27- Look at her go, look at her go! - That is fantastic.
0:41:29 > 0:41:31They are quite bizarre-looking fish, aren't they?
0:41:31 > 0:41:33They're very prehistoric.
0:41:33 > 0:41:35I used to think they were quite horrendous creatures,
0:41:35 > 0:41:37to be quite honest, until I started filming them
0:41:37 > 0:41:39and realised how beautiful they are.
0:41:39 > 0:41:41What I really love about them is the fact
0:41:41 > 0:41:44that the males and females work cooperatively,
0:41:44 > 0:41:47moving stones from the nest to the perimeter of the nest.
0:41:49 > 0:41:53There's no denying that these underwater oddities have evolved
0:41:53 > 0:41:55to stand the test of time.
0:41:55 > 0:41:57Even though these sea lampreys
0:41:57 > 0:41:59are about to reach the end of their life cycle,
0:41:59 > 0:42:02they have completed that essential task
0:42:02 > 0:42:04of producing the next generation.
0:42:07 > 0:42:10The lamprey may have a face that only a mother could love,
0:42:10 > 0:42:13but I love them for their weirdness.
0:42:13 > 0:42:17And of course, the UK is one of the key countries in Europe now
0:42:17 > 0:42:19- for the sea lamprey.- Absolutely.
0:42:19 > 0:42:21Very important that we look after them.
0:42:21 > 0:42:24And I've tried to go snorkelling with them every summer,
0:42:24 > 0:42:27every time since I first saw them, I have to say,
0:42:27 > 0:42:28I fell in love with them.
0:42:28 > 0:42:31And I suppose because any creature that's been around
0:42:31 > 0:42:34for hundreds of millions of years deserves respect.
0:42:34 > 0:42:37Yeah. You've got to respect the lamprey.
0:42:39 > 0:42:40Tomorrow on Wild UK,
0:42:40 > 0:42:43we turn our attention to forests
0:42:43 > 0:42:47and the wildlife that makes our wooded wildernesses their home.
0:42:47 > 0:42:50Lucy discovers a project that's helping turn the success
0:42:50 > 0:42:55of the pine marten in Scotland into something the whole UK can share.
0:42:55 > 0:42:58Colin journeys deep into Kielder Forest.
0:42:58 > 0:43:02And, well, if you go into the woods, you're sure of a big surprise.
0:43:02 > 0:43:06We go behind the scenes with the Wild Alaska bear team.
0:43:06 > 0:43:09Wonderful to be this close to a grizzly bear.
0:43:12 > 0:43:16You can keep up with the latest news from the Wild Alaska Live team
0:43:16 > 0:43:17all this week online.
0:43:17 > 0:43:23And join us again tomorrow morning, 9:15, BBC One, for more Wild UK.