Original subtitles

Canada -

the second largest country on Earth.

Famous for its epic wilderness.

From the Rocky Mountains...

..to the Great White North.

Breathtaking...

..rugged...

..and immense.

It's a rich and varied wonderland...

..which supports some of North America's most iconic species.

Theirs is a world of extremes.

Their life at the mercy of the elements.

Every season brings new challenges.

It'll take strength and tenacity...

..courage and resilience...

..skill and good fortune...

..just to make it through...

..a year in the wild.

Some say there are only two seasons in Canada -

the one with snow and ice...

..and the one without.

This year, it's the one with snow and ice that's dragging on.

Covering almost four million square miles, Canada is so vast that spring

arrives at different times in different places.

At Renault Lake, in Southwest Quebec,

there's a glimmer of hope.

Even a slow thaw is better than none.

This beaver survived the winter,

living off food he'd stashed under the ice.

But with gaps in the ice opening up,

he can finally bring his food to the surface and enjoy a meal outdoors.

His mate is heavily pregnant and almost ready to give birth.

But there's a problem.

Otters are heading their way.

And for the beavers, they're the neighbours from hell.

Sliding on their bellies to save energy,

they're keen to reach the open water,

where catfish gather in the shallows to warm up.

Fish form the bulk of an otters' diet,

but, given a chance, they will take beaver babies, too.

They're the only predator with

access to the underwater entrance of the beaver lodge,

where this female raises her young.

The male beaver tries to scare two otters away...

..but it only seems to encourage them.

He issues one last warning with a tail slap...

..and beats a retreat.

These otter twins are yearlings

and have all the skills to look after themselves.

Which is just as well,

because Mum sneaks off at every opportunity.

She's ready to breed again...

..and it doesn't take her long to find a mate.

In order to trigger ovulation,

they may need to mate many times...

..and each mating can last up to an hour.

It takes total commitment...

..and plenty of stamina.

Whilst the otters are entwined,

the male beaver sees an opportunity to strike.

It's a valiant effort...

..but it won't keep them at bay for long.

He'll do all he can to protect his young.

But with a late spring thaw and otters moving in,

the odds are stacking up against him.

While winter lingers on in the east...

..over 2,000 miles away, on the west coast of Vancouver Island,

spring is in full swing.

Air blowing in from the Pacific Ocean bathes the forest in warmth.

Rousing 7,000 black bears from hibernation.

An old female is one of the last to emerge.

She's an experienced mother

and knows that it's dangerous to wander far...

..with a tiny cub in tow.

Born blind and almost hairless just 12 weeks ago,

he's now big enough to follow Mum on foraging trips.

He still relies on her for milk...

..but, by copying what she does,

he can also get a taste for adult food.

Sedge is nutritious...

..but it does little to quell his mum's hunger pangs.

She lost a third of her body weight over winter

and needs food high in protein.

The only place to find that is on the beach.

At low tide, rocks brimming with mussels are left exposed...

..and crabs scuttle for shelter.

All contain vital calories for a nursing bear mum.

But they're not the only ones here.

This is where all hungry bears head...

..including the males.

And if one of them stumbles upon a little cub...

..he's likely to kill it.

It's a warm spring morning on Vancouver Island...

..and hunger has driven a black bear mother to the beach.

It's her cub's first trip out of the forest.

He must stay close to his mum.

Black bear males will kill cubs that aren't their own...

..and, out here, she's his only protection.

But it's also an opportunity for him to learn the art of crabbing.

The technique is simple.

Roll over rock and gobble up the tiny crabs underneath.

The first ones are too heavy.

The next are half-buried in the sand.

This one looks just right.

He puts his whole body weight behind it...

..and gets his first taste of seafood.

He's learning fast...

..and gaining in confidence.

But that can sometimes land a cub in trouble.

He's so engrossed in his new skills,

he fails to notice that Mum's moving on.

She's focused on finding the very best foraging spots...

..and soon moves out of sight.

Frightened and alone, he panics.

If his cries fall within earshot of a male,

they may have fatal consequences.

His mum quickly retraces her footsteps...

..and responds to his cries with a soft growl.

The cub rushes to greet her.

And learns another vital lesson.

If he doesn't pay more attention,

he won't even make it through spring.

2,000 miles due east of the bears,

far away from the warming effects of the Pacific Ocean,

lies Canada's oldest Provincial Park...

..where the spring thaw is well overdue.

But with each week gaining 17 minutes of daylight,

the air slowly warms.

And the ice finally gives in.

Triggering one the world's most magical transformations.

This wood frog spent winter in the deep freeze

with nothing to protect him from the elements.

Ice formed inside his body...

..stopping his heart and lungs.

Eyes, frozen open,

have registered nothing for almost six months.

But a little spring sun has the power to work miracles.

Muscles twitch...

..eyes clear...

..and he takes his first breath of the year.

Chemicals in his blood protect his cells from frost damage -

a clever adaptation that allows these frogs

to live further north than any other amphibian.

After thawing-out, it's business as usual.

It's the breeding season for wood frogs...

..so he heads straight to the nearest pond...

..to look for a mate.

An hour before sunset, the pond comes alive

with male frogs serenading the females.

Other amphibians here save the romance until well after dark.

Male salamanders spend most of their lives on land.

But as soon as there's a thaw, they gather in the shallows

to lay tiny parcels of sperm.

A gift for the female salamanders - when they arrive.

Females emerge from hibernation after the males...

..and this one's already late to the party.

She can't survive freezing like a wood frog,

so she spent winter deep underground.

The burrow she chose is over half a mile from the breeding pond -

a daunting distance for an animal with legs less than an inch long.

Crossing patches of ice is dangerous.

Spend too long here and her muscles will seize-up, leaving her stranded.

Made it,

but there's not a second to lose.

She's sensitive to light

and must fertilise her eggs before daybreak.

She chooses a sperm packet

and sucks it into her reproductive tract.

She'll lay about 200 eggs

and if any of her offspring survive long enough,

they'll make the same epic journey here next year.

2,000 miles away...

..back on the west coast of Vancouver Island...

..a series of low spring tides are due.

Bears leave the forest early, keen to reach the beaches...

..where a glut of mussels awaits.

Strong teeth make light work of shells...

..making it easy to access the juicy morsels within.

It's not fast food,

but this bear may crunch his way through hundreds of them every day.

As well as extra calories,

each mouthful provides him with a shot of vitamins and minerals.

He'll need all the energy he can muster in the weeks ahead.

The breeding season is here.

The air is thick with sexual tension

and bear emotions are running high.

For a young, inexperienced female...

..it's a tense and daunting time.

It's spring in Canada and things are hotting up on Vancouver Island.

It's the breeding season for black bears...

..and trips to the beach aren't just about looking for food.

This male is tracking a female...

..unaware that there's already one heading his way.

For a four-year-old female, that's just reached breeding age,

the first mating season is a bewildering one.

She's never had much to do with male bears before

and is naturally cautious.

Her first instinct is to flee.

But the male has her hemmed-in.

Eventually, she settles.

But the male's clumsy approach has put him on the back foot.

She's nervous and defensive.

He adopts a submissive posture.

And tries gently huffing to appease her.

But she's still too wary to allow him any closer.

If he's to father her first cub,

he'll have to be patient and wait until he's regained her trust.

3,000 miles east of the bears, on Canada's Atlantic coast,

lies the island of Newfoundland.

Nearly 6,000 miles of rugged coastline - hewn by wind and waves.

Spring here marks the beginning of a remarkable spectacle.

Gigantic monoliths of ice appear...

..in a stretch of water known as iceberg alley.

Carved from ancient glaciers in western Greenland,

the icebergs have been slowly drifting south

on cold Atlantic currents.

Many weigh in excess of a million tonnes...

..and are formed from the same 10,000-year-old ice

that sank the Titanic.

Whilst icebergs move down from the north...

..migrants return from the south.

Having spent winter in the Gulf of Mexico,

this gannet has flown over 2,000 miles to be here...

..as have over 20,000 other gannets.

Their final destination -

a 300-foot tower of sandstone, known as Bird Rock.

It's one of the largest breeding

colonies of gannets in North America.

Gannets mate for life,

but males arrive first to claim a nest site.

With so many birds, property gets snapped up fast.

Late arrivals must run a gauntlet of steely beaks.

With a prime nest site secured,

this male won't budge for fear of losing it.

All he can do now is sit tight and hope

that his mate will find him in the hullabaloo.

Soaring over the rock, a female signals her arrival.

It's a call her mate recognises,

even over the clamour of other birds.

He calls back.

And finally, after guarding the nest for a week, they're reunited.

They've not seen each other since leaving here last year

and waste no time renewing their bond by clattering bills.

The next four months are critical.

The gannets must mate...

..hatch an egg...

..and raise a chick...

..all on a patch of rock no bigger than a tea towel.

Further up the coast,

a female osprey has returned to her favourite nest site...

..where she watches her partner show-off.

They've been together for 13 years...

..but every spring he has to woo her all over again.

After displaying some flight skills,

he heads back to the nest to see if he's impressed his mate.

If she's receptive, she'll allow him to mate.

But she's not ready yet.

Until they've mated,

the female is free to leave the nest at any time.

If that happens, she may be courted by another osprey.

To keep her here, the male must ensure she's well-fed.

His favourite fishing spot is a sheltered lake,

just three miles inland...

..where the calm water makes it easy to spot fish.

But today the fish are deep.

To catch one, he must completely submerge.

That means hitting the water at 50mph.

Make a slight miscalculation...

..and he won't come back up.

It's spring on Newfoundland Island

and a female osprey waits at the nest.

Her partner has gone fishing three miles inland.

He lines up a fish...

..but loses sight of it at the last moment.

He resets,

makes a few final adjustments...

..and dives again.

This time, all he gets is a drenching.

But it doesn't dampen his resolve.

He just needs to get his eye in.

Hitting the water legs first...

..he closes his talons...

..and nets himself a trout.

It's not a bad catch,

but it's only enough for one.

With a hungry female to feed as well,

he must catch another soon.

Back at the nest...

..the female spots her mate returning.

He's been gone all morning...

..but comes bearing gifts.

This time, it's a nice fresh flounder.

She flies off to eat it alone...

..but she won't be going far.

With a well-established nest, and her partner hunting successfully,

this pair are on course to continue their long history together -

and breed once more.

Spring was late over much of Canada this year.

But with the northern hemisphere swinging back towards the sun,

days are still growing longer...

..and warmer.

Animals in Algonquin rise early

to make full use of the time.

Sapsuckers are a type of woodpecker...

..skilled at chiselling through the hardest Canadian wood.

This male has almost completed his nest chamber.

There's just a little more work required on the entrance.

Nearby, a male chipmunk is also busy...

..collecting leaves for his underground nest chamber.

Changing the bedding in his burrow regularly

helps to keep it free of parasites.

His cheeks can expand to double the size of his head,

allowing him to carry more each trip.

The less time he spends outside, the better.

Algonquin is rife with predators.

Black bears have been known to dig up chipmunks...

..but they prefer something more substantial.

Bears kill more moose babies than any other predator.

So, pregnant moose head deep into the forest...

..to find a secluded thicket to give birth in.

Her calf is less than a day old

and she's still getting used to her long, wobbly legs.

Feeding time is an opportunity to practise standing up.

Building up her strength is vital.

She could encounter her first predator at any time.

Most moose babies are born in a

two-week window at the end of spring,

so bears know when there's a fresh crop of moose calves about.

They'd like nothing more than to flush one out from the undergrowth.

They're one of the main reasons that half of all baby moose

don't make it through the first six weeks of life.

Until this calf can run,

her best chance is to lie low and remain hidden.

Her mum will defend her at any cost.

But with more than 2,000 bears, hungry and hunting,

this little calf faces a challenging summer ahead.

Next time...

..summer is coming and youngsters have to face some grim realities.

To survive in Canada, you have to fight...

..rob...

..and be on your guard.

Any that don't find their feet fast will perish.

Subtitles by Red Bee Media