Guide to Otters Springwatch

I'm on the cycle track

that goes from Bodmin in Cornwall

all the way up to Bristol.

And it takes you through some glorious countryside.

This bit here is particularly special.

I always stop here

because this seems like a perfect spot for otters.

And, in fact, there are otters here -

there's probably one watching us right now.

But even though I've stopped here literally dozens of times,

I've never seen one.

But I'm not that surprised.

Although otters are one of our largest carnivores,

they're incredibly secretive and hard to see.

40 years ago, otters very nearly became extinct in England,

yet they seem to be making a remarkable recovery.

But what we really know about them? Where are they? How can I see one?

In the next hour, Springwatch's confirmed otterholics,

Charlie Hamilton James and Simon King,

will delve into the secret life of the otter.

And Chris Packham will explore just what an otter's made of.

And I'll be delving into the otter's past,

looking forward into its future, and trying,

with the help of some simple detective work,

to see how you and I can actually see one for ourselves.

So welcome to the Springwatch Guide To Otters.

Meet the otter - one of our most charismatic animals.

It's inquisitive, playful, elegant,

but the otter has another side.

It's a skilled hunter,

fiercely territorial about guarding its patch. And what a patch!

Otters live in some of the most gorgeous places

in the British Isles.

They recolonised these islands after the last ice age,

and over 10,000 years, they've spread out from England rivers

in the south, right up the coast

to the northern most islands of Scotland.

They're generally solitary, secretive creatures

that like to keep themselves to themselves.

You might just glimpse a swirl here, or a whiskery snout there,

before it vanishes in the water,

leaving nothing but a trail of bubbles.

So what kind of animal is the otter?

It's time to meet the family. Chris.

Well, the otter is a member of the mustelid family of mammals.

There are 54 species across the world,

but we have seven in the UK, and here they are.

You'll certainly be familiar with some of them.

How about this little chap down here? This is the weasel.

They're ferocious little carnivores, armed with really sharp canine teeth,

and this one is especially designed

to dive down into mouse and vole holes,

where they predate those species.

It's slightly larger relative, the stoat,

does a very similar thing, except that it is after rabbits.

Over here, we have the polecat.

Now these are very closely related to

the domestic ferrets that people keep.

And then, the most arboreal of all of the British mustelids -

the fabulous and exquisite pine marten.

Once a species you could find all over the UK, but these days

sadly restricted to Scotland, although they are spreading out.

Perhaps the most familiar of all of them,

though, is this animal - the badger. And here you can see that,

typical of this group of animals, it has five non-retractable claws

on its front foot, because it's using those to dig its set.

That just leaves us with the two semi-aquatic species,

the mink and the otter.

Now, the mink here is not a native of the UK,

it was introduced from North America.

In fact, it's made a bit of a pest of itself.

But the otter is truly a native,

and when it comes to identification, well, look,

the mink is significantly smaller, so I think that

if you get a good view of an animal swimming through the water,

you shouldn't mistake anything in the UK for the fabulous otter.

And most of us, when we think about otters, you probably imagine them in

a river, but they don't just live in rivers, they also live by the coast.

Some people think that the otters that live in saltwater

and the otters that live in fresh water

are two completely different species,

but they're not, they're the same species, the Eurasian otter.

And of all the 13 different species of otter that live in the world,

the Eurasian otter has the widest distribution,

and if I had a map, I could show you.

Oh, blow me down! Good Lord, I do have a map!

So, look, you can see, in the pink,

that's where the Eurasian otter is distributed.

So the otters are here, here's the heartland in Europe,

but they go down south to Morocco, and all the way across here,

across the Himalayas, down to Indonesia in the south,

and now up here to Kamchatka Peninsula in the north.

But for our otters, although they're all the same species,

they do have two very different lifestyles.

On rivers in the south, otters are almost entirely active at night,

while the coastal otters of the north,

who rely on the shifting tides to hunt, are out and about by day.

One of the best places to see otters in the UK

are the Shetland Islands off the north coast of Scotland.

Here, the sea has battered the coastline over millions of years

to create 3,000 kilometres of perfect otter habitat -

a rocky coastline full of shallow pools,

with plenty of sea caves to rest up in.

So this is the ideal place for Simon King

to give us his first guide to otter watching.

So, Simon, when you're out trying to spot otters,

what's the first thing you look for?

Seagulls, obviously!

There's a black-back, great black-back,

and herring gulls, all scavenging birds, looking for an easy meal.

If you see any of those three species sitting on a rock,

looking down into the rocks,

it means it's watching an otter that's already feeding,

and then you can very carefully move yourself around

to get a view of the otter.

SEAGULL CAWS

Following them really closely is all down to field-craft.

If I'm to stand a chance of a very close view,

I've got to make my way down the beach,

and the only way I can do that is to move when the otter is underwater.

On the surface...

..and down. OK.

Otter dives rarely last much longer than 30 seconds,

so I don't want to move...

He's up.

I won't move for much longer than 20 seconds.

And down again.

OK, I'm just going to tuck myself into the rocks.

So it's absolutely vital that

the wind is blowing from the otter towards me.

That ensures that my scent doesn't reach the otter.

OK, it's got a big fish. It's coming in towards me.

Oh, that's beautiful!

Just look at that.

What a great view.

No more than that.

(I can't sit up.)

(She's started to look in my direction.)

To see an otter, like Simon, you've got to try and think like one.

Whilst he was in Shetland, Simon got to know

a couple of otter families, each living either side of a bay.

There was Ebb, and her cub on one side,

and Flow with two cubs on the other.

Beautiful views. This is Flow, off to the right, that's the adult female.

Her two cubs off to the left, 18 months old now.

Pretty independent, those cubs,

but they still depend on their mum for a certain amount of food,

and, of course, an enormous amount of care and affection.

They're a very, very close family unit, otters.

Look at that, lovely serpentine grace,

moving from land to sea as one,

and otters that swim together, dive together.

Look at this, one, two, three, all of them down, looking for food,

we thought, but then within about a minute or two,

the cubs were up on the surface having a complete barney.

Now, this isn't a scrap, this is just hi-jinks, having a good time.

But nothing being done with any serious aggression here.

This is the sort of behaviour you might see when otters

are courting, but right now this is just the youngsters playing together.

And then, look at this, he loses his mate. "Where's he gone?

"Where are you? Oh, there you are!"

He thought the game was over, then it's all off again,

they're just superb to watch.

Absolutely magnificent.

Oh, where is he gone? There you go.

Quick bundle, and then no sooner did they disappear

than one of them came up with a huge fish, a lumpsucker.

They went back into feeding.

And the game was over.

Twice a day, these otter families

have food delivered right to their door.

A rising tide fills the shoreline with a seafood smorgasbord.

Although their main diet is fish,

in Scotland, otters are very partial to crabs.

But whatever they are hunting,

otters are spectacularly manoeuvrable underwater.

How can an animal originally designed for life on the land

be so good in water? Over to you, Chris.

You've got to watch your fingers, but this is a fabulous place

to appreciate just how well the otter

is adapted to its aquatic environment.

I'm at the British Wildlife Centre in Surrey,

and these are obviously tame otters.

They use their rear limbs, which are well webbed,

to push that body through the water, and then they have that strong,

stout tail, which they use as a rudder.

The entire body is incredibly supple, it can twist and turn

and bend, and when they're swimming as fast as they can,

they undulate that body to improve their stroke, as it were.

They want to be as streamlined as they possibly can,

and, as you can see, they've achieved that

with a long, lithe, slim body.

Honestly, beautiful.

You know, when I was a kid, I was obsessed with otters.

I was so obsessed that my mother made a fake fur otter.

It was a terrible representation of this beautiful animal,

but I would wind it up at the foot of the bed and shine a torch on it

and squint to make it look real.

If this had happened to me when I was eight, I'd have burst.

I'd have burst spontaneously.

Aw, a childhood dream fulfilled.

But come on, Chris, focus. Back to the engineering.

To really understand how an animal works physically,

we need to look inside it.

We've got a fabulous opportunity to do that here,

with this articulated otter skeleton.

If we consider the vertebral column here,

it's got all of these flanges, and those are muscle attachment points.

Now, the bigger and broader they are,

the larger the muscle is that's attached to them.

So I can tell you, for instance,

that there was a lot of muscle tissue there,

and, therefore, this is a very supple and sinuous animal.

And let's look at the feet, because, on land,

this animal is walking on the soles of its feet, just like we do,

and that tells me that it's not fast-moving,

because, typically, animals which are fast-moving run on their toes.

Think of cats and dogs, and horses, of course.

But, of course, here, it doesn't need to be fast-moving on land,

what it wants is broad feet, which are webbed, as you know,

because these are used for pushing the animal through the water.

So what we've got here is an animal that's supremely adapted

for an aquatic lifestyle.

There's no better way to see this than when,

on a calm day in Shetland, Simon found an otter

swimming in gin-clear water.

It's really unusual to find a steep drop-off like this, with water

directly beneath that's shallow enough to attract an otter to feed.

And it's one thing to watch these animals on the surface, but look!

I have to say, this really is the clearest view

I have ever had of an otter hunting like this,

and it's immediately clear that it's not chasing fish directly,

or not at first, but instead... Ooh, there you go.

..charging after fish that it disturbs from under rocks

and through the seaweed.

It spends most of its time foraging through that weed in the dense,

dense bladderwrack and kelp.

Little bit of a breather. Again, you never get to see their feet

when they're on the water surface like this,

but you can just see, she's so at home, perfectly relaxed.

What a great view.

Now, Simon King is clearly a confirmed otterholic.

But there's one other cameraman who's always trying to get

even closer than Simon.

That is my good friend, Charlie Hamilton James.

I saw my first otter when I was 16,

and I'd gone to Shetland just to see otters.

Luckily, I've had lots of cups of tea,

so I'll be able to keep myself warm.

I think that's too cold down there.

The otters won't hang around long,

so I need to get on with the serious business of being

one of the only people ever to have swum with a truly wild otter.

Usually they're incredibly wary.

The slightest smell of a human and they're gone.

But in the water, my scent is hidden,

and whilst they know I'm here, they don't know what I am.

I can see an otter working the shore,

and I'm swimming gently towards it.

And then suddenly, it appears.

My first shot of an otter underwater.

It's incredible how close I'm getting,

and although inquisitive, it's still carrying on hunting and fishing.

As it swims through the water,

I can see for the first time how otters use their whole bodies

to propel themselves along, not just their tails and feet.

It's quite simply breathtaking to watch,

and I feel it can't get any better. But it does.

This bold and brazen dog otter is swimming up to investigate,

coming so close he touches my camera.

It really is a once-in-a-lifetime experience.

GARBLES EXCITEDLY

That is, without a doubt,

the best wildlife encounter I have ever had in my life, by a mile.

It is unbelievable.

Now, like Charlie and Simon, I've spent some time in Shetland.

DRAMATIC MUSIC

And it's not always sunny and serene.

The thing is, though,

no self-respecting mother otter

-is going to take her cubs out in that!

-HE LAUGHS

It takes a lot to stop an otter.

This mother and her cub are out fishing.

Even in gale force winds, they have to eat every day.

If they don't, they'll starve.

And surviving in these chilly North Sea waters

requires some high-performance equipment.

The otter's fur is short, fine, dense and velvety,

and it's also extremely good at doing two essential things -

keeping it dry and keeping it warm.

Let's take a closer look at the fur using this microscope.

I'll just focus it.

You can see that the coarse hairs there are what we call

the guard hairs. They're about 20 millimetres long, and they're covered

with a water-repellent oil, and it's these that keep the otter dry.

But if I part them

and we delve underneath into the under-fur,

these hairs are shorter, between 10 and 15 millimetres,

and they occur at an incredible density -

60,000 hairs per square centimetre

all over this otter's body,

and they are really good at keeping it warm,

because they trap a layer of air here

at a temperature ten degrees higher than the surrounding air or water.

And when it comes to staying warm in water, you've got to try hard,

because we lose temperature 27 times quicker through water

than we do through air.

Now, if you've got a coat like that, you certainly need to look after it.

And one thing you'll notice is otters spend a lot of time grooming,

particularly if they've been into saltwater,

because the salt leads to the breakdown of that oil

which is keeping the animal dry.

So they'll come onto land, actively look for freshwater to bath in,

and then spend a lot of time grooming, often in traditional spots.

At the end of the day, if you've got a coat like this,

you want to keep it in tiptop condition

so you're nice and dry and warm.

-HE SHIVERS

-I could do with a bit of extra under-fur myself, it's bitter.

Now, we've seen otters frolicking about

in broad daylight on the coast.

I don't know about you, but when I think about where an otter lives,

I tend to think about something like this - a river, freshwater.

In southern Britain, otters live not just on rivers,

but in lakes and marshes too - anywhere, in fact,

where there's water and plenty of bushes for cover.

Here it's much harder to follow their lives,

because on a river, otters come out at night.

There's no twice-daily tide bringing food,

but with dusk, the river comes alive.

Away from prying eyes, fish like bullheads and eels emerge.

And under the cover of darkness, otters come out to hunt them.

As the otters emerge, so does Charlie,

hoping to share their lives.

He's spent more time than anyone filming their movements at night.

Tonight he's using a thermal imaging camera,

which works by detecting heat,

and shows up any warm-blooded creature on the river.

I've got the ducks on it. They're coming down the river,

and the ducks... are right up against the edge.

Ah, it's really hard to see it. There's the otter.

I've got the otter, it's right near the ducks. They can't see it.

I can only just see the ducks.

Yeah, he's right next to the ducks.

There goes the ducks. Oh...

HE CHUCKLES

There's something very special about seeing an otter at night like this.

And I guess it's because you're seeing something

that you shouldn't really be seeing.

From all the hours he's spent watching them at night,

Charlie's noticed the otters are constantly alert.

They're hyper-sensitive

to everything that's going on around them.

OTTER SQUEAKS

The family cruise the river like a well-oiled hunting machine,

diving after fish,

rooting around rocks to dislodge crabs and crayfish.

Now and again they rest up in special places - their holts -

hidden behind bushes or perhaps beneath a tangle of tree roots.

This pattern of resting and hunting, resting and hunting,

is how they pass the night.

But I wonder if you, like me,

have ever wondered how on earth otters find food

in this murky, pitch-black water?

One of the ways the otter is going to be finding its food

is by using its whiskers -

these highly modified hairs we call virissae.

And they are extraordinarily sensitive.

Well, not the hair itself - that's dead -

but it's the tissue into which it's rooted that is absolutely packed

full of neurons, nervous tissue, and this transmits the information

to the animal's brain, and in otters,

that part of the brain is significantly larger

than in other species that are not so reliant on their whiskers.

But, you know, it's not that the whiskers actually have to touch

their prey, or anything they're looking for,

because they are sufficiently sensitive

to be able to detect the vortices.

Now, that the churned up water that fish have left behind them

when they're swimming through the river.

And what's even more astonishing is that these animals

can actually detect which species of fish has been swimming there,

even when the fish is long gone.

That's remarkable.

That's an astonishing bit of biology,

but when it comes to hunting,

it seems that otters may have an even cleverer trick up their sleeve.

Now, after hours and hours of patient observation,

Charlie Hamilton James thinks he's discovered something

completely unexpected.

So, Charlie, I'm imagining I'm an otter,

I'm swimming around at night, in possibly murky water,

that's a tall order.

Now, apart from using... sensing movement of fish,

what other senses could I use to hunt?

I've got this theory that otters also use smell underwater.

Yeah, but they are mammals like us, so we have to go...

-HE SNIFFS

-..and they're holding their breath.

So how on earth can an otter smell underwater?

Well, otters, they're supposed to have their nostrils

completely closed underwater,

but I used to feed the otter in my garden,

because I was rehabilitating one to release him,

and I used to put her fish in the river,

so that the rats didn't get it.

And she could find it. Wherever I put it, she could always find it.

So I was always thinking, "How can she find it?"

-It's not moving at all.

-No, so the whiskers thing,

that's not doing anything.

It's dark, and the river's all murky, so she can't see it,

so it's got to be something else going on.

-OK.

-So, I thought, "Well, I'd better try and film it."

I invented some kit. It's an underwater camera.

And I also put a nappy in it, because it leaked.

THEY LAUGH

And then I put it in the river,

and I put a couple of infrared lights on it

to light it up. So it's still pitch dark.

I tied a dead fish to a brick,

I stuck it in the murky river at night,

and it found it straightaway.

-How? Can we see it?

-Yeah, have a look.

-Here's the dead fish?

-Yeah.

And it's very quick, look, the otter comes in, picks it up, it's gone.

Now, how does that tell us that it's smelling the fish?

Right, well, at first, I didn't know anything else was going on,

other than it had found it.

So I had to go back, and look at this thing

and look at this thing, and try and work out what was going on,

and this is what I noticed. If you play it back really slowly...

There. There's a little bubble.

I thought that was just its nostril, but just that little flash there...?

A little flash, it's putting a bubble out,

and it's sniffing that bubble back in.

And that's going to get loaded with scent and the chemicals of the fish.

And then once it's worked out what it is, pick it up, swim off with it.

It actually exudes a bubble of air,

that somehow captures the scent, and it sucks it back into its nose.

-Absolutely.

-Did you just come up with that?

Is that just the Charlie theory from nowhere?

No, it's not. You know, I knew something was going on

because I knew they could find them, and then I'd seen a BBC documentary,

and in it they featured star-nosed moles -

these very cool critters that hunt underwater.

And what they'd done is they'd basically filmed them

in very slow motion and proved that they are smelling

by putting out bubbles and sniffing them back in again.

-The scent is in the water?

-Yeah.

But I put cameras above the water.

I wanted to look down on, to see exactly what was happening,

so not just underwater. And you can see, she comes up the river,

and she goes past the fish,

and then she suddenly makes a very sharp turn, and grabs it.

-So she clocked it.

-Somehow she's detected it.

And a bit like the wind, the river's going in one direction,

so any scent's coming down the river, and when she went past it,

she obviously clocked it, and came back round and grabbed it.

So whatever it is, she clearly can do it. She is picking up that scent.

And it looks like she's using the Charlie bubble scenting theory.

I think that's probably what they'll call it from now on!

Science in action, folks.

Now we know otters are supreme swimmers,

they have a highly sophisticated sense of both touch and smell,

all of which combines to make them very, very good at catching fish.

And that skill would inevitably bring them

into conflict with humans.

For hundreds of years, in Britain, otters have been hunted.

Organised hunting of otters was going on

way back in the 12th century, partially to control their numbers.

But by the 20th century, otters were being hunted purely for sport.

Someone who used to hunt them was James Williams,

now one of the foremost otter experts in the country.

What was the structure of the hunt?

Well, I've got a picture here of my father,

who was the master of the hunt.

And there he is with some of the officials and the hounds...

-Great photo.

-..and he organised where the hunt would go

and then they would meet at 10 o'clock or 10.30

at a bridge or a house and set off to try and find an otter

and see if they could have a hunt.

I've got to say, you've got the most wonderful collection of dogs in this, haven't you?

-They're purebred otter hounds.

-Oh, are they?

-These are purebred otter hounds?

-Yes, purebred otter hounds.

Here's some more and you can see there

what fine, upstanding animals they are.

They're wonderful, wonderful hounds and I love them.

-And everyone's on foot. Am I right? It's all...

-Yes.

-No horses or anything like that.

-No, no horses. All on foot.

-All on foot.

And long poles which people sometimes say they were spears, they're not,

they're just walking sticks because you've got to cross the river.

Now, with a fox hunt, the fox will be in a bush or a...

But an otter's going to be a much harder quarry, I would think,

to find in the first place.

Because there are far fewer of them,

the first thing you have to do is find where the actual otter

has gone in the night and follow its scent, which we call the drag,

and hope that eventually you would locate the otter.

How many separate otter hunts would there have been

up and down the country?

About two dozen. Most places were in the territory of an otter hunt.

What sort of effect did the hunting back in those days

have on otter numbers overall?

Very little effect.

We know that otter hunting was going in the reign of King John

and otters survived perfectly well.

I think the hunts were fairly beneficial

in that they stopped people trapping, because it was much more fun

to see if you could have a hunt and a day with your friends

than to set a trap and go in the morning and find a mangled corpse,

so I think the hunt, in fact, had a slightly protective effect.

But for all that, between the 1950s and the 1970s,

there was a sudden and dramatic decline in otters.

The hunts were the first to notice there was a problem

and they immediately sounded the alarm.

But the numbers of otters continued to fall,

and in 1978, otter hunting was made illegal.

Something was devastating the population

and, finally, after lengthy investigation,

the cause was discovered.

Toxic chemicals, introduced in the 1950s,

were being used by farmers to kill pests

and prevent fungal infestations.

The poisons were washing into waterways

and building up through the food chain.

Otters are a top predator in our rivers

so the toxins accumulated in their bodies to dangerous levels,

causing blindness and fertility problems.

By the early 1980s, otter numbers had crashed

by up to 90% in England -

they were on the brink of extinction.

But a fictional tale about the life of an otter in North Devon,

written at the peak of the hunting period,

had begun to change people's attitudes.

It was Henry Williamson's Tarka The Otter.

Oh, this is Tarka when a child.

"The eldest and biggest of the litter was a dog cub

"and when he drew his first breath he was less than five inches long

"from his nose to where his wee tail joined his backbone."

That's a bit twee, isn't it?

"His fur was soft and grey as the buds of the willow

"before they opened Easter tide."

That's all right.

"He was called Tarka, which was a name given to otters..."

"..many years ago by men dwelling in hut circles on the moor.

"It means "little wanderer" or "wandering as water"."

Now, I read Tarka as a child

and it's a mixture of poetry and raw, almost brutal, reality.

And Williamson was a realist.

He even joined to his local otter hunt to make sure

the book was as accurate as it possibly could be.

But when he wrote Tarka The Otter 85 years ago,

otters were still plentiful.

The great crash in their numbers hadn't actually started.

So this isn't really a book about otter conservation,

but it did start to change the way that we think about otters.

And that change continued with the publication of this book,

Ring Of Bright Water by Gavin Maxwell, in 1960.

And this book, and the film of the book,

cemented a change that was already happening,

turning the otter from vermin into a treasured part of British wildlife.

Otters had had a make-over.

Now they were playful and friendly

and there was an outpouring of support for them.

Otter conservation hit the political agenda

and they finally became legally protected

in England and Wales in 1978

and just a few years later in Scotland.

Where are you? Come on.

Meanwhile, new conservation groups had sprung up

and one of these was the Otter Trust,

set up in 1972 by Philip and Jeanne Wayre.

They were so passionate about otters they bought a farm in Suffolk

and created large breeding enclosures by a lake.

Rescued otters were taken in and bred in captivity

and in 1983 the first three otters - two females and a male -

were released into a river in Suffolk,

where it was hoped they would start a wild population.

So the otters took a massive hit,

but then the chemical pollutants were banned.

The otters got legal protection

and a lucky few even got a helping hand directly.

We had paved the way for their recovery - now it was up to them.

Good news for the otter's recovery

is that it can breed at any time of year

and produce a litter of two or occasionally three cubs.

The den might be an old rabbit burrow

or a hole in a tangle of tree roots.

It just needs to be snug and secluded.

OTTERS SQUEAK

The cubs grow quite fast,

playing and sparring with each other to build up their strength.

It's not until they're about four months old

that they first venture, tentatively, out into the water.

The family call to each other with piercing whistles

to stick close together in the dark.

OTTERS WHISTLE

Mum teaches them how to hunt underwater

and over the next eight months

they'll learn all the skills they need to become fully independent.

So if you ever see a group of otters together like this,

it's invariably a mother and her cubs -

the male dog otter doesn't stick around.

Whether on a river or by the coast, dog otters are loners.

As soon as they're fully grown they move away from home

to find territories of their own.

And this they guard aggressively against anyone.

One of the ways they define their territory

is by marking its boundaries with scent.

Otter spraint - their poo - is a language all of its own.

Left on rocks or sandy mounds, it's a warning to keep out,

a message that Simon has clearly failed to heed.

And here it is, on all of the little high points.

This rock, a great mass of spraint here, here.

Behind me, here.

And if you get a close look

and there are still the odd bubble on, then just keep still

cos the chances are the otter's only just been here

and it's somewhere nearby.

Spraint is actually a complex method of communication,

and just how complex has only recently become clear.

Oh, yeah. Look at that.

You can clearly see the reflective qualities there

of a lot of fish scales.

But, of course, to the otters,

this material has another very clear function

and it's all about communicating through smell

and I've got some fresher samples that have been collected here

that haven't dried out and I'm going to give them a bit of a sniff test.

Now, some people say that it smells like freshly mown hay,

some, jasmine tea, but to me,

that's just pure otter.

The smell is made up of 100 different components,

but 17 of those are used by the otters

to identify the spraint to an individual level.

So if an otter was to sniff this itself

it could tell you whether that was male or female,

five, six, seven, eight years old,

whether it was sexually mature, whether it was sexually active.

It's Brian and he's had a fish masala, without any doubt.

Now we can take DNA from this spraint

and identify the otters down to individual level.

So, you see, far from being a nuisance and something a bit quirky,

otter spraint is incredibly useful both to man and beast.

Over the past few decades, signs such as spraint and paw prints

have been used to try to chart the otter's comeback in England,

and although overall this shows encouraging signs of recovery,

it's difficult to know exactly how many otters there are now in the UK.

Trying to identify individual otters using their tracks

and their spraint is notoriously difficult, but in the future

this new DNA technique should make it much, much easier

and help us build a more reliable picture of overall otter numbers.

Research so far suggests otters are steadily recovering,

with numbers estimated at somewhere around 2,000 in England

and perhaps 8,000 in Scotland and Wales.

In Scotland, where hunting's now been banned for 30 years,

Simon recently found signs that otters are getting bolder.

This is an otter trap, or, as they are known locally,

an otter "hoose", built to trap otters for their fur.

This would have been the area that the otter was attracted to going in

and here there would have been a wooden sliding trapdoor

connected to a string that went inside the structure

to a pressure pad and if the otter walked inside,

touched the rock, the door would close behind it.

And then when the otter hunter came by on his rounds

he'd lift one of the big rocks at the top, kill the otter, take it out.

Now, of course, otters are fully protected

and what is so fantastic and ironic is that this otter trap at least

is being used very, very regularly by the local otter, or otters,

as a resting place, and their sign is everywhere.

There's a spraint here which is no more than an hour old

and I can see where the animal has collected bedding

and made a lovely, warm, cosy nest just inside.

How strange that a structure designed to kill otters

should prove to be a des-res.

As they slowly spread across the UK,

otters are finding new friends to help them on their way.

On a rain-soaked day last year

I went to help some volunteers, led by inventor Chris Matcher,

making specially constructed otter holts.

'I've put up plenty of bird boxes but an otter prefab?

'Like any flatpack, well, you know how it goes.'

-D?

-D. Where's D?

-Which way round does it go?

-It should be the other way around.

-That should be that way round.

B. That's B.

(It never goes smoothly.)

'But, seriously, when you're not filming,

'this holt can be put together in under an hour.'

Girls with power drills - very exciting!

Done. Chris, thank you for a marvellous day out.

-Look what we've created.

-Thank you very much.

I shall volunteer for more of this sort of work(!)

Let's get out of this!

Excellent! And helping otters isn't just about building nest boxes -

sometimes it means playing surrogate mum.

When these three orphaned cubs were found by a roadside,

a local wildlife sanctuary took them in.

The cubs had never been in water

so when the time was right, a swimming lesson was arranged.

Over the next 18 months,

the cubs were taught to hunt and fend for themselves

and eventually they were put back into the river

very close to where they were found.

The one thing that has helped the otter's recovery

more than anything else is the clean-up of our rivers.

And although pollution is still a problem,

many rivers have improved dramatically.

Otters are a litmus, a test, for the health of a river

and their presence shows that now many of our rivers

are the healthiest they've been for 20 years.

And that's good news,

not only for otters, but for all our river life.

It's not just our cameras catching glimpses of otters -

here are some of your photos from around the country,

courtesy of our Flickr photo group.

No longer restricted to coast and countryside,

some 21st-century otters are living right among us.

In the cathedral city of Winchester,

CCTV captured these remarkable images.

A mother and no fewer than three cubs

playing quite happily directly underneath the city's mill.

The Wildlife Trust now estimate that otters are established

in at least 13 urban centres.

In Manchester, evidence of otter activity

was recorded for the first time since the early 1900s.

And in Newcastle, Simon was thrilled by the sight of an otter

in the heart of the city.

That's the trail of bubbles that every otter watcher wants to see.

I find it truly wonderful

to think that as we drive over these bridges in city centres,

scenes like these might well be playing out

under our wheels all over the country.

And this is testament to an enormous turnaround

in the way we treat our waterways.

The fact that otters and herons can find sufficient food

in these urban rivers and pools is a clear sign

that these freshwaters live up to their name - just that, fresh...

..and life-giving.

Now, otters are naturally long-distance travellers

and that's what's bringing them into our cities.

But not everyone is quite so pleased to see them in the suburbs.

Some garden ponds have been receiving

some very unwelcome visitors.

Imagine a small pond with a big, sluggish koi carp in it.

To an opportunist like an otter, it's irresistible.

It's not just ornamental fish ponds that are getting hit.

Up and down the country,

otters are becoming a real headache for commercial fisheries too

and I'm off to Somerset to find out exactly what's going on.

This lake is owned by an angling club in Bridgwater

and today its vice president, Danny Danahy,

is having to restock it with carp.

Now, Danny,

I can't help noticing the whole of the lake is like Colditz.

You've had to go to some really extreme lengths to protect this.

-Yes.

-What has happened?

-Over the last four years, we've put in approximately 4,000 fish.

-Right.

Last Thursday, we had about 50.

Mainly roach, small bream.

The 1,500 carp we put in more or less gone.

That must have been crushingly disappointing for you.

Terribly. Terribly. It's costing us an awful lot of money.

The fence, we've put the fence up to try and stop

what we believe is the otter doing it.

'There are a variety of different animals it might be,

'not just otters.

'Mink will go for roach and bream,

'and with a slump in fish stocks out at sea,

'more and more cormorants are coming inland to hunt.'

What's led you to think that it is the otter in general?

Fishermen are actually seeing them on the big lake over there.

We've also found paw prints, spats, dead fish.

-Dead fish, yeah.

-Dead fish.

From the photos of fish carcasses taken by the club,

it does look like otter.

They'll go for carp because they're slow and easy to catch

and they typically pick out the muscle just behind the gills,

leaving the rest of the fish untouched.

We believe that they're coming from the river,

-which is in that direction.

-Ah.

-OK?

And we believe that they're using that as a superhighway

to come off onto lakes like ours.

And they're opportunistically looking for feeding stations

and they've found your fisheries here.

Found our fishery and helped themselves.

As otters are legally protected, Danny's had to invest

in putting up some sort of barrier to keep them out.

And you had to sink that into the ground?

That's gone into the ground, about 18 inches into the ground.

-It's not a cheap option.

-No, no. Very, very expensive.

For a lot of people, it could be the difference between being in business

-or going out of business, you know?

-Yeah.

And stock is the most important thing.

Hmm, that's tricky.

And the growth in commercial fisheries and fish farms

happened when there were hardly any otters around.

And now the otters are making a comeback...

Well, for an otter, this must be like finding

a free all-you-can-eat buffet.

I suppose the only option is to think very seriously about fencing.

All these sightings of otters could give the impression

that their comeback is complete,

but, in fact, whilst it looks like they've recovered their range,

they definitely haven't recovered their numbers.

But they ARE coming back.

And that means we've all got a better chance

of seeing one for ourselves.

So how do we go about it? Well, I know just the man.

OK, Charlie, I've got maybe ten minutes.

I am desperate to see an otter. How do I see one?

Well, you're probably not going to see one, to be honest,

but there's a whole selection of signs that you can look for

to tell you if there is an otter there, at least.

So we have to turn otter detective.

I know the basics of what we're after -

paw prints, holts in the banks

and the heady smell of jasmine tea from their spraint -

but I'm hoping Charlie can fill me in with some fieldcraft tips.

I've got the right man - he's scaring me to death

with gruesome tales of their leftovers.

If an otter eats a trout, it'll hold it like that on the body

and start with the head.

You know what I mean? Till it's gone.

You'll find the crayfish, it'll be the head and the claws they'll leave.

If you find the back of a crab, often they'll have a single hole in it.

You know, the canine of the otter has gone through it.

Rat tails, so they've eaten the whole of the rest of the rat

and they've just left the tail.

'OK, Charlie, enough. Show me some hard evidence now!'

What's the very first thing in your top ten otter signs?

-What are we looking for?

-This, basically, look.

All these little dotty things?

Look, there you go. All the way, straightaway.

Any nice wet bit of mud along the edge of the river,

if it's got otters, it's generally going to have footprints.

That could be a dog to the untutored eye.

What are we looking for that makes it otter?

Well, key thing is, it's got five toes, an otter,

and dogs and foxes have got four. But they're so distinctive.

Look, you can see these teardrop paw marks,

like upside-down teardrops, straightaway.

They are sharp at the end, like that.

What sort of size?

-Look at that!

-All right, let's measure one.

I always have a little measurer.

You're looking at about five centimetres.

-I would have said that's sub adult, teenager, maybe.

-Teenage otter?

-Early teens.

-Early teens otter?

-Yeah, you know that it'll have Mum with it.

So if there's a mum and a cub,

at somewhere on this river will be a dog otter,

cos he'll have a huge territory,

encompassing several different females.

So you know just from seeing these small prints

there are probably three otters here,

-even though we are only seeing the prints of one.

-Amazing.

Now, Charlie, this is interesting.

It looks like a sort of a trail here going up there. Could that be otter?

Absolutely. Otters cut corners all the time,

and they cut corners when they are going upriver.

They don't need to cut corners when going down river

because they've got the energy of the river

so they're not expending any energy, but when they're coming upriver,

it's much easier to get out and cut a corner off.

Now, obviously, otters are fishing a lot of the time,

but sometimes they're not, they're just on a mission.

And you're trying to film them,

trying to keep up with them and they're just...

for two or three miles, some of them, and you think, "Where are you going?

"Are you late for the cinema? Is the fishmonger shutting?"

I don't really get it, but this is when they're cutting corners.

Otters on a mission. He knows what he's on about.

OK.

O0h, it's a bit deep there, Martin. You have to go tiptoes.

-That is the classic otter hole.

-That is an otter hole.

Yeah, it's a hole in the root system of an ash tree,

which the otters love to dig up into.

So where's the entrance? Is the entrance that bit there where it's sort of a bit muddy?

Yeah, and you can just see the hole in there.

There's not just one here either.

So there's another one 200 metres down there...

-Right.

-..under a hazel tree. And all the way up the river,

every few hundred metres, there's another one.

That's a classic rock -

the otter is going to come up, he can go out and poo on there.

Oh, look at that. Hey-hey!

-Ooh.

-Isn't it lovely?

-Look at that!

Now, most otter scientists and enthusiasts,

they like to pick it up and move it around in their hands.

Not me. I use a stick.

Are you listening, Chris Packham?

-OK, so you can see they've been eating crayfish here.

-Look at that.

The big bits of shell, and that's why it's red.

Well, here's the crayfish, but this is very different.

It's green, for a start.

It's very fresh and it's green.

-They've been eating fish here.

-I can see little fish bones inside that.

This is... I mean, it's almost still wet

so you're talking within the last 48 hours.

And, interestingly, sometimes you find these

and they've got bits of moor hen in them. They love moor hen.

This is a signalling system

so they're going to drop a little bit here and a little bit further up

-and a little bit further up.

-Yeah.

I mean, they don't sit there for 15 minutes reading National Geographic.

MARTIN LAUGHS

Are there any final tips?

-Well, if you want to see an otter...

-I do, I do.

..you've got to get the wind direction right.

So what you want is you want the wind coming off the otter

and blowing into your face and if you do that

-you've got a pretty good chance of seeing one.

-Brilliant.

There we are - the Springwatch Guide to Otters.

We've learnt what an otter is, where it lives,

what it gets up to on our coasts and rivers...

..even in our cities.

We know its history, and, most importantly,

how to go about seeing one.

But there is one last question.

Did I, during the making of this film,

get to see an otter for myself?

Yes!

Charlie, Charlie, Charlie!

-I just saw an otter!

-No!

-I swear to you.

-Where?

I just saw an otter swimming straight towards us up here.

Just literally in this pool here!

-It was coming straight towards us.

-Did it see us?

Yes, because it was only there, feet away from us.

The first time in my whole life.

We've been here two minutes!

But I've only seen about five otters here in the daytime

in my whole life living.

It was an otter in that pool not 20 feet away

from where we are right now.

I never dreamt I would see a river otter for myself

and we'd only been there about two minutes.

It just shows it can happen.

But I promise you one thing -

if you ever get to see a wild otter for yourself,

you will remember it for the rest of your life.

Subtitles by Red Bee Media Ltd