NARRATOR: On North America's east coast
wildlife adapt to the rise and fall of the tides.
Tides provide a much-needed resting place for mammals,
and unveil a feast for thousands.
On the jagged coast of Canada's Eastern shore
a delicate and diverse ecosystem
thrives on the fringes of the continent.
Welcome to the Wild Wild East.
The tide is an awesome force of nature.
175 million tonnes of water
flow in and out of the Bay of Fundy
twice each day.
The waters carve and shape the shore,
transforming the landscape.
The creatures here evolved and adapted
to exploit this ever-changing habitat.
Great blue herons living inland
get up to 40% of their diet from rodents,
but here, it's 98% fish,
easily snatched from the shallow muddy puddles
of low tide.
Crows and ravens also scavenge along the rocks
for stranded crabs and crustaceans.
Low tide is a picnic laid out twice daily
for those living along the shore.
But in just hours it will all be gone.
The tides in the Wild Wild East are the highest
anywhere in the world,
rising as high as a five story building.
Bluffs will become islands.
Mudflats will become the ocean floor.
Duncan's Cove, Nova Scotia
is a rocky headland
eroded out of granite barrens
by eons of pounding surf.
Even in the middle of summer
the ocean here remains chilly.
This pod of grey seals
doesn't seem to mind at all.
Their protective layer of blubber keeps them warm,
allowing them to stay in cold environments
all year round, even in winter.
Now the tide is high
and they're coming up for a breath of fresh air.
Grey seals spend most of their lives in water,
and they're most often spotted just like this.
It's a behavior called bottling,
bobbing in the water with just their heads sticking out,
to breathe and look around.
Below the surface, the grey seal moves
with an agility that seems improbable
for a creature that weighs twice as much
as a linebacker.
Their webbed hind flippers propel them forward,
and they use their front flippers to steer.
Their flexible spine lets them twist and turn
through the water and hunt down fish on the fly.
The grey seal shares the oceans of the Wild, Wild East
with its very similar looking but smaller cousin,
the harbor seal.
The easiest way to distinguish between the two species
is to look at their heads
from the side.
Grey seals have a straight profile,
like a horse's head.
Its unflattering scientific name
translates to hook-nosed sea pig.
The harbor seal has a clearly-defined muzzle,
which is why its scientific name means "sea dog."
The harbor seal gets its common name
because it's the seal most often seen close to land.
Both grey seals and harbor seals feed, breed and thrive
in the cold waters of the Wild Wild East.
All seals are semi-aquatic,
alternating between life on land,
and underwater.
When the tide is high, haul-out spots on land
are harder to find.
It's easiest to stay wet,
and seals have specially evolved
to spend most of their time in the ocean.
Like all mammals, seals need to hold their breath underwater.
When they dive, their heart rate slows down
from 120 beats per minute
to as few as four.
That reflex allows them to use less oxygen
and stay underwater longer,
up to a half an hour.
Their nostrils close to seal up their airway underwater.
Their big eyes give them excellent underwater vision,
for spotting cod and other undersea delicacies.
Seals have been known to travel great distances
in search of food or a mate.
Harbor seals are found in the Atlantic
and the Pacific and as far south as Mexico.
But grey seals stick to the waters of the North Atlantic.
And Nova Scotia is home to the world's largest colony
of grey seals.
More than 100,000 congregate each winter
to mate on Sable Island,
110 miles from the mainland.
But even when they're not breeding,
seals usually don't stray too far
from places to haul out.
High tide is high time for swimming.
But low tide will offer a chance to relax.
Later today, these rocks will be more exposed,
and will give the seals some place to rest.
On another shore of the Wild Wild East
a seasonal visitor
is about to transform the landscape.
The tide is going out at Johnson's Mills, New Brunswick,
a small town on the edge of the Bay of Fundy.
The sleepy mudflats of this shoreline
are about to be flooded with life.
It's beginning now, off in the distance.
These are semipalmated sandpipers,
about 100,000 in all.
They're incredible migrators
flying 10,000 miles a year.
They've come more than 1,800 miles to get here.
Flying up to three days at a time without rest.
They spent the winter and early summer in the Arctic
breeding, nesting and caring for their young.
And now, They're on their way to South America,
about another 2,500 miles.
Flying that far requires a lot of fuel,
and the occasional pit stop.
And that's why they're here,
for a few weeks of rest before moving on.
The Bay of Fundy is a stopping point
for almost every semipalmated sandpiper in the world.
Conservationists consider them near-threatened,
so places like this, called staging points,
are critical to the survival of the species.
The mud flats of Johnson's Mills
offer plenty of food and elbow room,
the perfect place for sandpipers to rest,
regroup, and refuel.
The tide is out completely now.
As the water pulls away, it reveals a seafood buffet
for the little semipalmated sandpipers.
They hunt and peck, spearing the mud
for the crustaceans, worms and other creatures
left behind by the changing tide.
Few places in the world expose such massive mudflats
at low tide.
Nine square feet of mudflat
contains as many as 100,000 mud shrimp.
That's a good thing
when there's 100,000 mouths to feed.
There's plenty for everyone.
Biologists think the sandpipers pick this place for a pit stop
because of the abundance of food,
and because the wide open mud flats
allow them to see any predators on the horizon.
The sandpipers feel around for movement in the mud.
They search by touch, for tiny shrimp and other creatures,
by jabbing around with their squat black beaks.
They gorge here, and double their weight in just two weeks.
They're not the only ones taking advantage of this free lunch.
This black bellied plover is looking for sandworms
and small crabs.
He's also refueling for a long migration,
and is taking advantage of such a large tidal zone.
Plovers are an entirely different family
of wading birds,
and they have a different hunting technique.
They sprint through the shallows
until they spot something tasty, then snatch it up.
As opposed to the steady probing technique of the sandpiper.
Soon they'll all be moving on.
For the harbor seals of Duncan's Cove
low tide offers the chance for some well-deserved rest.
Hauling out onto the rocks
is an important way for seals to conserve energy.
Constant swimming burns a lot of calories.
In a single day, an adult harbor seal
must eat as much fish as 64 cans of tuna.
Relaxing on this remote outcropping
also keeps seals safe from ocean predators like sharks,
and isolated from terrestrial predators
like bears and coyotes.
During molting season they scratch and scrape
on the rocks to shed old skin.
Seal bodies just aren't adapted well for life on land.
Their limbs are shorter than any land mammal,
and what looks like their armpit,
is actually their wrist.
So graceful in the water,
they're reduced to humping around on land,
flopping themselves forward on their bellies.
That's even more work than swimming.
It's much easier to just stay put.
Even though harbor seals are mostly solitary,
they become temporarily gregarious at haul out sites.
A good spot is hard to find,
so everybody tries to get along.
Big males sometimes scrap during mating season,
but this is a time for chilling out.
So long as they maintain some personal space
dust-ups outside mating season are pretty rare.
Off to the side, a grey seal, uses the same haul out spot,
but keeps a healthy distance.
Grey seals are a lot bigger,
and have been known to eat harbor seals.
But there's no chance of a surprise attack here,
they're equally inept at moving around on land.
Seals closest relatives aren't marine mammals
like whales or dolphins,
they're actually more closely related to bears and dogs.
You can sort of see it,
if you imagine their blubbery bodies
enveloped everything except their hands and feet.
There's a clear pecking order here on the rock,
with the youngest seals on the outside,
closest to the water.
They're not big enough to compete with the big males
for the prime spots further up.
And sometimes mother seals leave their pups
close to the water, so they can go find fish
and check on junior without hauling out again.
These aren't this year's pups,
but they're still young.
They're probably two or three years old.
By the time they're six or seven years old,
they'll be full-grown like these guys.
The oldest males could be as much as 35 years old.
They'll all loaf around until the tide rises again.
The sandpipers at Johnson's Mills, New Brunswick
need their rest too.
They've come a long way and have a long journey ahead.
Some birds sleep on one foot,
to keep one leg warm at all times.
Or they can tuck both in to get cozy.
They do this because the sandpiper's bare legs
are the place they lose heat fastest.
Birds need to maintain a high body temperature
to burn calories fast enough for the tremendous effort
required to fly.
Resting their head on their back
and nuzzling it into the feathers,
is another way to conserve heat.
And, if a bird gets too warm, it shakes out its feathers,
to release the heat trapped near its body.
A single bird has thousands of feathers.
Preening is a sort of preventative maintenance
on the sandpiper's flight gear.
A gland near the tail produces an oil
that the bird smears on its beak
then spreads over all its feathers.
It helps with waterproofing and removes dust and dirt.
The sandpipers peck away parasites
while smoothing and shaping each feather's position
in anticipation of the journey ahead.
The particular size and shape of the Bay of Fundy
amplifies the effects of the moon
on the Atlantic's tides.
In flat areas, the difference between high tide and low tide
is the distance of 10 football fields.
When the tide is in, the mud flats vanish.
The rising waters push the semipalmated sandpipers
into a tighter formation.
The security advantages of crowding like this
seem obvious, more eyes and ears,
keeping a watch for predators.
When trouble starts the whole flock reacts as one.
Scientists have long studied
the other functions of flocks.
It's tough to see where one bird ends and another begins.
Maybe this confuses and confounds predators.
The security of the crowd will soon prove critical,
because high above, somebody is watching.
To some predators, the flock of sandpipers
represents opportunity.
Peregrine falcons are high-speed airborne predators.
A diving peregrine plummets faster
than any other creature on the planet.
Two hundred thousand wings begin beating,
the flock moves with a coordination
some have compared to telepathy.
The flock is on the move.
Scientists puzzle over how they all know to move at once.
Now watch this...
the peregrine flies directly into the swarm.
Look again, the falcon's a blur
blasting straight into the mass of confusion,
the flashing of feathers.
The peregrine only needs one bird,
but today, he can't hold onto his lunch.
Even if the falcon had been successful,
one bird out of 100,000 is a pretty successful defense,
from an evolutionary standpoint.
But the flock is sufficiently spooked.
These shores are a dangerous place.
They're moving on. Heading south,
following an ancient migratory path,
orienting themselves by the sun,
the stars and the earth's magnetic field.
They won't rest again for days.
Back in Duncan's Cove, the rising tide
is slowly evicting the seals
from the granite outcroppings along the shore.
The waves lap the ledges where the seals haul out.
Soon this island will disappear
until the tide goes out again.
Before long, it's even more than a seal can handle.
It's goodbye to the land-lubber's life for now.
After six hours of maximum rest and relaxation,
it's time to go.
They spend most of their lives in the water,
where their big bodies swan around
with the grace of a ballerina.
They're built for the swim,
but adapted for the rise and fall of the tides.
In the early half of the last century,
people hunted grey seals to near extinction
on the American shores just south of here.
But after decades of conservation
grey seal from Canada's Wild Wild East
have been discovered repopulating
the coastal waters of New England.
The tide may have finally turned in their favor.
Poets wax philosophical about the turning tides
symbolizing the never-ending passage of time.
They are relentless,
predictable,
and reliable.
But they also represent change.
In nature, the receding tide reveals opportunity,
to rest,
and to feed.
As it rises, the sea reclaims
everything it exposed before.
The creatures living here
evolved to exploit the rhythms
and cycles of nature,
the rise and fall of the water,
and the ebb and flow of life
in the Wild Wild East.
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