♪♪ GIAMATTI: All along the New England coast, ospreys are icons of summer.

They are specialists -- known as the finest fisherman among all birds of prey.

They signal the change from long, dark winters to long, sunny days.

But ospreys are not here on vacation.

They've come to take up their greatest challenge -- to compete with each other in tight places... to fend off thieves... and predators... and to raise tiny, helpless chicks... into daring aerial acrobats.

♪♪ For an osprey, summer is no day at the beach.

It's an annual call to battle -- and the toughest test of everything they are.

♪♪ ♪♪ [ Birds calling ] GIAMATTI: What inspires a bird to leave his home in the tropics, where the weather is warm and the fishing is easy?

♪♪ Much of the answer remains a mystery, but it comes from a need deep within him.

♪♪ The hero of our story is an osprey -- a bird of prey... and he's on his way north -- answering that inner call.

♪♪ From somewhere along the coast of South America, he's set his course for one specific shoreline, some 4,000 miles away.

♪♪ Our osprey, it turns out, is a New Englander at heart... and he's heading home.

♪♪ Weighing just three pounds, he travels light and fast... and all alone.

♪♪ He flies up the East Coast of the United States -- heading straight into his toughest time of the year.

♪♪ Four weeks into his journey, he leaves New York City behind and turns northeast along the shore of Long Island Sound.

♪♪ ♪♪ Spread out below him is an osprey's moveable feast... a watery maze left by glaciers many eons ago.

♪♪ ♪♪ This is the delta of the Connecticut River.

♪♪ Dredged and farmed for centuries, it's now hemmed in on both sides by houses and humans.

♪♪ Yet it remains a wild place... still governed by the tides and the seasons... and it's here that the osprey was born.

♪♪ It's late March... and he's back in his home waters... where he first tasted fish... where he first learned to fly.

His focus turns immediately to the most important piece of real estate in the marsh.

It's an old piling standing just off an abandoned island.

This was his true destination all along.

It's just a ramshackle pile of sticks, but this is his nest, and he's come home early to reclaim it.

After a long winter, it's a wonder it's still here.

Yet before he can even start on repairs, there's a crisis -- eagles!

This is trouble.

Bald eagles are bigger, stronger than our osprey... they're known to attack osprey nests, taking eggs, even chicks.

♪♪ They may also be looking to build a nest of their own -- in his marsh!

♪♪ The eagles appear to be a young couple, and not very experienced... and the male takes the bait.

♪♪ The osprey is battle tested... and launches his attack from above.

♪♪ Though he's much smaller, he's more agile in the air.

♪♪ Even an eagle respects the power of an osprey's lethal talons.

♪♪ For the young eagles, it's easier -- and safer -- to simply move on.

♪♪ And so begins another New England summer... a season of one challenge after another... and the best way to start is with a good breakfast.

♪♪ Fish are his only prey... and fishing is what an osprey does best.

♪♪ His long, narrow wings, up to six feet across, enable him to actually hover -- like a giant kingfisher -- while his keen, bright yellow eyes penetrate the waters below.

♪♪ But it's the dive -- wings drawn in, eyes lined up behind wide-open talons -- that brings all his strengths together in one pure motion.

♪♪ ♪♪ No other raptor can totally submerge like this.

♪♪ His feet and talons are custom made for grasping a slippery fish.

♪♪ Even his dense, oily feathers are specially designed to shed water -- with a mid-flight, shaggy-dog shake.

♪♪ Our osprey is not the only one concerned about his home in the marsh.

Year-round residents rely on this patch of wild country, too.

A woodchuck is out of his burrow, planning his next move.

Woodchucks hibernate through the winter.

The mound he has created sits at the entrance of his winter den.

Now, he's ready to shift up-country to a summer burrow he also maintains.

Out in the tall grass, a fox takes notice.

She's a capable predator of woodchucks, but at the moment, she's more interested in his plans to leave.

A woodchuck burrow is a masterwork of home security and protection from the elements.

The fox is getting ready to have a family.

She needs this den and is quick to claim it for herself.

[ Birds calling ] It's morning in the marsh, and one by one, ospreys are arriving from far-flung places.

Many have spent the winter along rivers in the vast Amazon Basin.

Now, they converge in the delta of the Connecticut River, more than 150 ospreys in just 15 square miles.

Osprey nest platforms dot the marsh.

They're additional nest sites built to help the birds recover from the toxic devastations of DDT.

For the savvy resident gulls, all these summer raptors are rivals... and potential marks.

The largest, the Great Black-backed gull, has been king of the beach all winter.

He's used to getting his way.

♪♪ He sees an osprey with a fish -- and he wants it.

♪♪ ♪♪ But now, it's beak against talon... ♪♪ ...and the better weapon wins.

Our male has been waiting for one special osprey to come home to the marsh.

♪♪ And right on time, she arrives.

♪♪ She's the partner he's counting on to make the summer a success.

♪♪ This will be their 10th season together.

But their long fidelity is not exactly to each other; it's the nest they return to each year -- the nest they build and defend together.

But first, they must get reacquainted.

Nothing is taken for granted.

He greets her with the perfect gift -- an impressive stick for the nest.

♪♪ ♪♪ Next, he offers her a fresh fish.

He's both a builder and a provider.

♪♪ ♪♪ Soon, they are working on the nest together, stick by stick.

♪♪ ♪♪ ♪♪ As the structure grows stronger, so does their bond.

♪♪ They take their courtship to the air, flying in unison.

♪♪ They have become a team again, a perfect pair.

♪♪ Tiny tree swallows are courting and building nests, too.

They prefer natural cavities in standing dead trees.

But such nest sites are hard to find.

So there's considerable excitement over this prime, old woodpecker hole.

Hopeful house hunters are eager to see inside.

But, of course, it's already occupied.

The best places always are.

The ospreys are having a housing crisis of their own.

They want to nest up high, but even with all the platforms, there are not enough sites for the birds that have come to breed.

Young, less experienced ones lose out.

Their only way to get a good nest site is to steal one.

♪♪ ♪♪ A young osprey with ramped up hormones launches a direct attack on our pair.

♪♪ It's a rash move with little chance of success.

The pair is strong, and they know their jobs.

He heads up to provide air cover over the nest.

♪♪ ♪♪ She hunkers down to protect their property.

♪♪ Young birds keep coming, but they can find no opening in the pair's defenses.

♪♪ Young challengers aren't likely to overwhelm ospreys in their prime.

♪♪ They're reduced to nesting attempts out on the marsh flats.

A nest out here is open to predators from every direction.

It's always in danger of flooding.

♪♪ Yet they decide any nest is better than no nest at all.

♪♪ So they build... and mate... and take their chances.

Back at the island nest, the structure is now fit for service.

♪♪ The male launches into his most impressive display.

♪♪ Climbing hundreds of feet in the air, and carrying a fish for maximum effect, he starts the show.

♪♪ He performs dramatic loops in the air -- where every other osprey can see him.

♪♪ It's called a "sky-dance."

Accompanied by a distinctive, high-pitched call, it's a show of stamina, of bravado.

♪♪ Far below, his mate calls back.

♪♪ Perhaps it's an encouragement... for when he returns, they mate.

He turns his talons inward before carefully resting them on her back.

His touch is remarkably tender.

They will mate many times over the next two weeks.

Then she will lay a clutch of beautiful brown eggs into the soft center of the nest.

The marsh has seen many changes in its long, ice-age history.

Yet washed by tides and nourished by the river, it remains so fertile, it still feeds multitudes when they need it most.

It's early May, and a flock of dunlin has arrived.

They are joined by sandpipers and plovers... whimbrels and yellowlegs... all finding rich pickings in the mudflats.

Hundreds of thousands of shorebirds are stopping at essential marshes like this on their way north.

They're going to the high Arctic to breed -- if they can stock up on enough fuel to survive the trip.

[ Thunder rumbles ] At the nest, a raucous set of house sparrows has moved in and is busy making nests of their own inside the ospreys' great pile of sticks.

The quiet single-family home has turned into a lively little village.

Magnanimously, the ospreys don't seem to mind.

The female has been sitting for 37 straight days.

Every day, the male has faithfully brought her fish.

This time, she rises... to reveal, at last, his reward.

♪♪ This is what their partnership has been all about.

♪♪ ♪♪ We cannot read their inscrutable faces, but we can see how careful they are to protect their tiny chick from their talons.

♪♪ Within moments, a ritual begins that will play out every day for the next two months.

Dad brings in a fresh fish, Mom tears tender pieces of it and delicately feeds the hungry new mouth.

♪♪ But soon, everyone's exhausted by the whole thing.

♪♪ ♪♪ ♪♪ The eggs are laid three days apart and hatch in the same order.

Now, a second little chick is also eager to be fed.

Good parenting will help her catch up with her big sister.

One egg remains.

But the two active chicks need constant care.

As the female broods the chicks under her warm feathers, the last egg sits out in the cold.

♪♪ Finally, with his two older siblings fed and quiet, the third baby osprey breaks out of his shell... and joins the family.

♪♪ ♪♪ He's so weak and tiny compared to his two big sisters, he can't seem to get any attention.

He can't even manage to get up.

He struggles and struggles... ...while his sisters eat and eat... ♪♪ ...and then finally, that little mouth in the back, the one that needs it the most, gets its first taste of fish.

♪♪ His sisters aren't pleased about sharing.

But his mother seems to know what she's doing.

Day by day, all three chicks are growing, even though he remains the smallest.

[ Bell clanging ] ♪♪ At the fox den, it's an important night.

Dad sets off to hunt, and under the cover of darkness, the tiny kits, now about five weeks old, take their first foray outside the den.

♪♪ Six roly-poly little foxes tumble out, followed by their surely exhausted mother.

♪♪ Both parents hunt now, bringing meal after meal home to the den.

♪♪ Some nights, it's a mouthful of voles, on another it's an enormous rabbit!

♪♪ Including themselves, they have eight foxes to feed.

[ Birds calling ] The marsh is now bursting with new life.

Part land, part river, part salty sea, it provides such a rich livelihood to so many families, it's among the most prolific nurseries in nature.

In their coveted tree hole, the tree swallow parents are coming and going with insects for their brood of five.

Two white-tailed does bring their fawns out of the forest to the edge of the shore.

Behind them in the trees, a red-shouldered hawk feeds her little chicks.

The fox kits are playing in the perfect afternoon.

Yet they've already discovered that not every day will turn out well.

One is severely injured... and instead of six, there are now only five.

♪♪ Their salt marsh is as rough and wild a place to grow up as any wilderness.

The year is swinging into summer -- the High Season on Long Island Sound.

The fishing grounds of the osprey have become a playground for beachgoers and boaters -- all enjoying a bright afternoon.

When it's hot, everyone heads for the water.

Even a deer enjoys a swim -- and paddles out for a summer retreat on the osprey's island.

Our pair has new neighbors.

A dead tree some 30 yards behind the pilings is now hosting the beginnings of a new nest.

They must be young builders.

It's late in the season to start such a thing -- and our pair takes no notice of them.

In their nest, the three chicks have been eating, sleeping, and growing stronger.

Their mom is still painstakingly feeding each one, but the little male is still much smaller than his two big sisters.

But he's been gaining a lot of attitude along with a little weight.

He doesn't win many tussles with his bigger siblings, but he's putting up a fight.

Their mother, who has been devotedly keeping them warm, now has to worry about keeping them cool.

But they are on their way to solving that for themselves.

Their feathers are coming in... one of nature's best inventions for moderating temperature.

And their looks are changing too, suddenly taking on the daunting aspect of raptors.

They're well on their way to becoming the fierce birds they're meant to be.

Yet they still patiently take one offered bite at a time, more like three well-behaved children than mighty predators in training.

As they grow, their demand for fish does too.

[ Calling ] The female is constantly asking the male for more food... but he already knows his job.

♪♪ He's out fishing, of course.

This is what he came 4,000 miles to do.

♪♪ He needs to see a fish to catch it, and he has 15 hours of daylight here at the height of the season.

That's a big help with a family of five to feed.

♪♪ He also provides quite a menu; he serves up a fluke, then a winter flounder, a porgy, and a menhaden.

♪♪ The chicks consume them all -- learning the taste of each different fish... while their dad takes a moment to power wash his talons.

♪♪ Three weeks after hatching, all three chicks are growing fast.

The little male is still the smallest.

He's in that "awkward" stage.

Like his "osprey suit" is too big for him.

But the fact is, he will always be smaller than his sisters.

As in all birds of prey, females will be up to 30% bigger than the males.

Perhaps that extra size helps them get through the demanding weeks of sharing their food with three extra mouths.

[ Calling ] Their mother continues to call... and the stress on her is starting to show.

She looks thin -- and hungry.

And despite the bounty of fish in the sound, his job is getting harder, too.

The population of the marsh has boomed.

Seagulls and cormorants have taken over rocky offshore islands to raise chicks, too.

The demand for fish has really ramped up.

♪♪ ♪♪ It takes an extraordinary effort for a three-pound bird to lift a fish out of the water.

But the bigger challenge now is holding on to it.

♪♪ ♪♪ Osprey against osprey is a test of strength in the air.

♪♪ The bird carrying the fish is handicapped.

♪♪ It takes powerful wings indeed to stay out in front -- especially when the fish itself is still putting up a fight!

And ospreys aren't the only pirates in these waters.

♪♪ Double-crested cormorants usually dive for their fish.

♪♪ Now, one has the nerve to pursue our male straight into the sky.

♪♪ ♪♪ It's a big mistake.

♪♪ Upon delivering the catch to the nest, the male turns -- to deliver a message to the cormorant colony.

♪♪ He begins with a fly-by... then, he picks a target.

♪♪ The colony is suddenly wide awake.

Everyone is instantly aware of the talons descending from above.

♪♪ But now, he's just trolling them... just making a point.

♪♪ ♪♪ He's the top gun here.

He's the bird of prey.

As the last of the day fades in the sky, night steals into the marsh.

Out in the salt meadows, an osprey sits atop an impressive stack of sticks.

But nearby, another female has barely any nest at all.

She must be part of a very young pair that hasn't learned how to build.

Suddenly, she's disturbed.

♪♪ It's a coyote.

♪♪ Casually, she takes the only egg the young osprey managed to lay.

♪♪ The giant stick nest fares no better.

♪♪ Raccoons make a tidy meal of every egg they find.

♪♪ In merely a moment, this nesting season is over.

♪♪ The osprey returns... and searches for her eggs... but all she can do is pick up the pieces.

♪♪ There will be no chicks in her nest this year.

♪♪ In fact, there'll be no chicks in any of the osprey ground nests anywhere in the marsh.

One by one, they will all be raided and ruined.

It's one of the hardest lessons an osprey must learn.

♪♪ There's a new, restless energy at the island osprey nest.

The chicks have full-sized talons now, but they still don't know how to use them.

They're almost the size of their parents, but their juvenile feathers, trimmed in creamy white, and their bright orange eyes mark them as mere teenagers.

[ Calling ] They're always hungry... and quick to cry about it.

Dad obliges with a fish and departs.

Now, no parent feeds them.

[ Calling ] Their mother simply stands by.

She's fed each one every morsel they have ever eaten -- until now.

They no longer need her constant care in the nest.

♪♪ It's the beginning of the end of an osprey family.

♪♪ Their mother is the first to leave.

She's given all she has... and having fulfilled her mission for this summer, she slowly heads south to rest and recuperate.

♪♪ But their father continues to bring food to the chicks for several more weeks.

The young male is quick to claim the latest fish.

As he grows more aggressive, arguments break out.

The sisters, once so far ahead of him, now wait for him to finish.

[ Thunder rumbles ] The nest is feeling smaller and smaller... ...and he's eager for a wider world.

Even a torrential downpour doesn't dampen his mood.

It's exhilarating!

♪♪ ♪♪ He achieves a brief but thrilling lift-off -- his very first moment out of the nest.

♪♪ ♪♪ In the coming days, the young male takes to floating above the nest, getting a feel for the wind.

♪♪ He was the last to hatch.

Now, he's the first to fledge... ♪♪ ...and his sisters seem impressed.

♪♪ He graduates to short trips... ♪♪ ...mastering take-offs and landings... almost.

♪♪ Inspired, his sisters begin to stretch their wings.

♪♪ Soon, all three siblings are soaring over the marsh.

♪♪ But the nest is still a source of security.

They often come home and settle in for the night.

♪♪ It's mid-August.

Another osprey summer on the Connecticut coast is coming to a close.

The male of the island nest brings one last fish to the fledglings he has nourished all summer.

They may not know it yet, but their childhood is over.

♪♪ Their father's work is done.

He's defended his nest against all comers and fed his family for months.

He's been fierce and devoted.

He is everything an osprey needs to be.

♪♪ Now, the long days of fishing in the north are over.

♪♪ Ospreys fly from summer to summer, and it's his turn to head for the sunlight of South America.

♪♪ The young male is still reveling in his newfound joy of flying.

♪♪ He seeks out other fledglings for mock battles.

♪♪ It's both play... and practice.

♪♪ He'll need to be good at it.

He'll need the skill and courage of his father.

♪♪ And all those fish he probably took for granted he'll now have to catch for himself.

♪♪ Dad made it look so easy.

♪♪ A rainy day doesn't help at all.

Not even his father could catch a fish he couldn't see.

♪♪ But no one teaches an osprey how to fish.

♪♪ ♪♪ It just comes to him... a gift... from all the generations of ospreys before him.

♪♪ It's the end of the season on Long Island Sound.

♪♪ Every evening, thousands of tree swallows fill the skies, intercepting a feast of insects on their way to warmer weather.

♪♪ Before long, the flock grows to a million strong... ♪♪ ...swirling in syncopation... ♪♪ ...preparing for their migration to the Gulf of Mexico.

♪♪ It's the last great celebration of summer.

♪♪ The young ospreys linger in the only place they have ever known.

But temperatures are dropping.

Fish are heading into deeper water.

The fledglings must be on their way.

♪♪ Finally, our young male takes to the sky.

♪♪ How he will find good wintering grounds remains a mystery.

♪♪ The dangers that lie ahead for him we can scarcely imagine.

♪♪ But if fate is kind, in a few years he'll return... to compete for a place in the marsh of his birth.

♪♪ The birds of summer have all flown.

♪♪ For those left behind, it's time to face the coming cold.

♪♪ The marsh bows down to winter.

♪♪ ♪♪ It, too, gets to rest and replenish, preparing for all the wild travelers that will need it... ♪♪ ...when it's spring again... and the ospreys come home.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.

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