[water splashing] [ethereal music] [birds chirping] [triumphant music] - Because of their isolation, the Galapagos Islands are a natural laboratory of evolution.

Strange new species found nowhere else on earth have evolved there from those few creatures which were accidentally stranded on the island's harsh shores.

Hi, I'm George Page for "Nature," and while it's the Galapagos isolation that has made them so important to science, starting with Charles Darwin, in our final program about the islands we look at those creatures for which the oceans were not a barrier.

Seabirds, albatrosses and boobies have been visiting the Galapagos for millions of years, and they have not interfered with the evolutionary process.

But about 450 years ago, very recently in evolutionary terms, man made his appearance in the Galapagos.

And as we'll see, he has had a profound impact.

[dramatic music] [beaks chattering] This strange ritual could happen in only one place in the world, an island called Espanola in the Galapagos Archipelago.

The islands are famous for unique species such as the giant tortoise.

Some of the seabirds are unique too.

But most come here just to nest.

This is the story of those ocean travelers.

[ocean roaring] The waved albatross nests only here on Espanola.

Most other bird travelers nest in many parts of tropical oceans.

But the Galapagos Islands have a special attraction for many species of far-ranging sea birds.

These are blue-footed boobies, a relative of the Atlantic gannet.

And a brown pelican, a Galapagos subspecies.

Frigate birds, the pirates of the air.

Two species nest in the Galapagos.

And then the masked boobies; they nest on many islands in the Galapagos group.

Some of the seabirds like these swallow tail gulls are native to the islands.

But our focus is the blue water voyagers and the factors that draw them to the Galapagos.

An incoming flight of red-belled tropic birds, perhaps the most graceful of all the sea birds that migrate here to breed.

They seek nesting holes in the lava.

[birds chattering] The Galapagos belong to Ecuador.

They lie 600 miles west of South America and consist of 13 main islands and about 43 eyelets in isolated rocks.

All are visited by nesting seabirds.

All are volcanic and look inhospitable.

But these barren islands are very attractive to seabirds.

Although on the equator, the Galapagos lie in the path of food rich cold water currents.

From time to time, these currents fail, but usually they produce fish in abundance.

When the complex system of ocean currents brings up wellings of nutrients to the islands, fish of all sizes abound.

These rainbow runners are in the middle range.

They're being panicked by a larger predator.

In this case, a mass attack by blue-footed boobies.

[birds cawing] [ocean rushing] Certainly one of the most bizarre of wildlife spectaculars is found on the flat island of Espanola, home to breeding colonies of the waved albatross.

Their courtship must rank is one of nature's noisiest, as well as complicated, nuptial ceremonies.

[beaks clattering] [birds squawking] The routine follows a set pattern.

It invariably includes bowing, bill fencing, calling and solo clicking of bills.

It usually takes place close to the proposed nest site.

Waved albatrosses don't make a real nest, though they sometimes gather a little nearby vegetation and arrange it around the hollow where they've lay their single egg.

This bird is shedding salt water through its nostrils, so it's obviously come in recently from the sea.

The egg weighs half a pound.

Rearing young is a slow process for all albatrosses.

The egg will take two months to hatch.

Even after egg laying, courtship continues.

The pair will share the brooding and feeding duties, so it's important that the bonds between them is kept strong.

Takeoff is a perpetual problem for a bird with narrow wings and an overall span of eight feet.

A headwind is essential.

Often it's to be found only on the beach.

So the birds waddle down there from the colony to wait for wind.

[birds cawing] The waved albatross reached the Galapagos ages ago and settled down.

But other more far ranging species have also made the Galapagos home.

Here, and part of the collapsed volcano on Isabella, the largest, island is the home port of one of the Archipelago's most exciting ocean travelers.

Tucked away and one of the many small craters is the breeding colony of that spectacular plunge diver, the blue-footed booby.

And there are the famous blue feet.

The female in the foreground is slightly larger than her mate.

The pupil of her eye appears larger too.

And as a voice, when he whistles, she hawks.

Three species of booby, the masked, red-footed and blue-footed all travel to the Galapagos to nest.

But the blue-footed outshines the others in spectacular performances.

The feet up landing is all part of a performance designed to impress a mate.

As is the high stepping march that follows.

Anything, it seems, to show off those startling blue feet.

That's the male with his head feathers fluffed out.

To attract a mate, he'll turn his wings nearly inside out.

Sometimes the sky pointing, as it's called, is done to impress prospective partners flying overhead.

This pair has probably already accepted each other.

Some more high stepping as a prelude to mating.

Adult seabirds of the Galapagos have little to worry about from predators, but the Galapagos hawk is always on the lookout for unguarded young.

The hawk, a species unique to the islands, is really a buzzard.

There are only a few hundred of them.

They feed mostly on carrion, but also kill lava lizards, small iguanas and juvenile boobies, which is what these two young hawks are eating.

You can tell they're immature by their light, streaked plumage.

There's that unmistakable buzzard-like silhouette.

The Galapagos hawk still thrives on Isabela, while there's some islands it never colonized, such as Genovesa.

However, the ocean travelers who arrived to nest on this island have other enemies.

In the low scrub of Genovesa, is one of the main breeding colonies of great frigate birds.

They are ocean travelers themselves, but when breeding they stay based in the islands for some time.

They feed their offspring for up to 18 months.

That red throat sack is inflated when the male becomes excited in courtship, a process which takes about 20 minutes.

Occasionally the red membrane gets punctured in fights between males.

When it's blown up, he sits with his head propped on the pouch, waiting for a female to fly over.

Sometimes he even gets airborne, with his red balloon tucked under his chin.

When a male spots a likely female flying over, he vibrates his wings and fires a machine gun burst of high pitched gobbling at her.

[bird chattering] Groups of males usually display close together.

If a female is enticed down, the males give a harsh rattling sound.

When she accepts one, she answers his calls and nods your head from side to side.

Unsuccessful males move off to join another display group.

[birds chattering] Aside from mating and feeding, the major preoccupation of frigate birds is piracy; stealing anything from anybody or everybody, starting with nesting material which they happily thieve from each other.

[birds squawking] Right beside the frigate birds on Genovesa, nest the second of the three booby species of the Galapagos.

The red-footed boobies.

Red-foot behavior is quite different from that of their blue-footed relatives.

To begin with, they're tree nesters, an unusual habit for a seabird.

It seems odd to see a web footed bird gripping a branch as tightly as a crow or a sparrow.

While the blue-foot is an inshore fisherman, red-foots feed far out to sea, largely on flying fish.

This particular red-footed booby is having so much trouble nest building that she might well regret her species ever chose to nest in trees.

But there are worse things to cope with than an uncooperative twig when setting up house.

Red-footed booby nests are a prime source of nesting material for raiding frigates.

The frigate may be the finest flying machine in the world of seabirds.

Half their weight is in their flight muscles.

The ratio of wingspan to weight is the greatest of any seabird.

Their fork tails can be trimmed instantly as rudders to change direction.

They can soar effortlessly, or turn in their own length to catch a fleeing booby with a crop full of fish.

This dog fight is with a red-foot returning from fishing.

The tactic is to scare the booby into disgorging its fish, which the frigates then catch in mid-air.

It's probable that they can tell whether a booby is worth chasing by its call.

It makes a different sound when its crop is full of fish.

If they keep up the pursuit, they're always successful.

[birds cawing] The third booby species in the Galapagos is the masked booby.

Ecologically, it fits in between the other two species.

Whereas the red-foot fishes far out to sea, and the blue-foot close inshore, the masked booby fishes somewhere between the two, so the three species seldom compete.

The masked lays two eggs and usually hatches two chicks, several days apart.

And that's where the strangest difference between the three species lies.

Because they're about five days apart, one chick is always far bigger and stronger than the other.

As soon as it's able the large chick evicts its weaker sibling from the nest.

The parents don't interfere.

So only one chick is raised.

The weakling becomes so much biological waste until a scavenger disposes of it.

The sacrifice of one chick seems to have nothing to do with the available food supply.

The two eggs probably act as an insurance policy.

If the first chick dies, a second one hatches five days later.

If the first is healthy, it drives the newcomer out of the nest.

Either way, the boobies are left with the one chick they're capable of raising.

The Espanola mockingbirds are quick to take advantage of the situation.

[birds cawing] But, as so often, it was the frigate which got the prize in the end.

When it comes to general harassment, it's always the frigate birds which steal everything, including the show.

[mischievous music] [bird cawing] This time the target is the tropic birds carrying small fish back to their nests in the lava tunnels.

[mischievous music continues] This tropic bird didn't escape attack even after landing, but the frigate, a juvenile, misjudged its approach and crash landed.

[dramatic music] Tropic birds, which plunge dive for their food like boobies, are comparatively slow flyers.

They're no match or a single pursuing frigate, let alone a whole squadron of them.

[dramatic music] It was inevitable that the most rapacious of all ocean travelers would eventually find his way to the Galapagos.

In 1535, man first landed on the islands.

But as this graffiti encrusted cove on the island of Floreana attests, many others followed.

At first it was pirates who found the Galapagos a convenient base.

They hollowed out these caves in the soft rock to protect their stores.

It was these buccaneers who first introduced black rats to the islands with disastrous results to the native wildlife.

Then between 1780 and 1860, it was British and American whalers and sealers who invaded the Galapagos.

And did irreparable damage to the animal populations.

The captains quickly discovered that the Galapagos offered an unrivaled and apparently limitless supply of fresh meat.

The giant tortoise was conveniently packed for easy loading and stacking.

Most important, it would keep in good condition, in fact nearly as good as the day it came aboard, for up to a year.

The tortoise answered all the requirements of a hungry and protein deficient whalers crew.

It's estimated that in about 80 years these ships took over 100,000 giant tortoises.

They killed them not only for food, but for their fat.

Large numbers were rendered down to produce barrels of cooking oil for their voyages.

Whalers and sealers brought some of the subspecies of Galapagos tortoises close to extinction.

Ironically, the whalers had less of an impact on the animals they took as prey.

But it was the presence of great numbers of whales that brought many of the ships to the islands in the first place.

The whalers had found rich, little hunted waters around the islands of Fernandina and Isabela, where sperm whales especially abounded.

The sealers did vast damage in two ways: they not only helped decimate the tortoise populations, but they killed tens of thousands of the unique Galapagos fur seals for their skins.

One sealer, Captain Benjamin Morrell, recorded that he killed 5,000 fur seals in two months.

By the 1930s, the Galapagos fur seal was nearly wiped out.

Today it's protected and its numbers have recovered.

The first settlers arrived at the turn of the century.

They let loose domestic animals such as these donkeys and far worse, goats.

Donkeys damage some vegetation but goats eat everything.

Today, the national park conducts systematic campaigns against them and other feral animals.

But only their total eradication will ensure the survival of native animals and plants.

Feral cats are especially hard to control.

After a generation or two, escaped cats become completely wild.

Young iguanas are very easy prey for them.

So are the young of flightless birds like penguins and the Galapagos flightless cormorant.

In addition to the cats, escaped dogs have bred in the wild and become relentless hunters.

But cats, because of their innate hunting skills, are one of the most harmful animals introduced by man.

Together with the black rats which prey on the eggs of ground nesting birds, they're a serious menace.

Man settled on only four of the 13 main islands.

On Santa Cruz, there are two farming communities in the moist zone in the central uplands.

There's also a reserve for the Santa Cruz race of giant tortoises.

Here the interest of domestic and wild animals don't clash, but it isn't the same story everywhere.

While the total human population of the Galapagos is only about 10,000 people, it's growing at 4% each year.

As it grows, the conflict between the native wildlife and man is bound to increase.

The reason why introduced animals are so dangerous to the native species can be seen in these scenes of our camera team on location.

Galapagos creatures are completely tame.

They never encountered mammal predators until settlers and ships brought them.

So the wild animals of the Galapagos evolved no fear of man and his domestic animals.

Native species became easy targets for feral cats, dogs, black rats and omnivorous pigs.

Even the Galapagos hawk, one of the island's few predators, shows no fear of man.

Charles Darwin commented, "A gun here is almost superfluous, for with the muzzle of one I pushed to hawk off a tree."

Seabird colonies anywhere are vulnerable to rats, cats and dogs.

In the Galapagos, the seabirds are not only remarkably approachable, the roughness of the terrain makes it extremely hard for conservationists to control the animals with prey on them.

Even in the seas around the islands, man exerts pressure.

As the frigate birds well know, they're rich in fish.

Each year there are more local fishing boats.

This means more fishermen ashore to swell the population, and more fish needed to feed that population.

Fishing must be managed at sustainable levels.

Fortunately, not all human activities have been harmful.

In 1959, Ecuador declared the Galapagos a National Park.

Nine years later, the Ecuadorian Park Service came into operation.

Realizing the worldwide importance of the Galapagos, Ecuador is trying to protect them and their unique wildlife.

In 1961, the park got an important ally, the Charles Darwin Research Station was established at Academy Bay on Santa Cruz.

Its mission: to carry out scientific research, plan conservation programs, and assistant training guides and wardens.

One of the programs, the National Park and Darwin Station set up early on, was the breeding in captivity of endangered species in order to return them to the islands where the populations had become dangerously low.

One of these was the Espanola tortoise.

When the Darwin Station was set up, the Espanola tortoise seemed doomed.

The few survivors were in competition with goats for the meager vegetation on Espanola.

The tortoises were so scattered they probably hadn't bred for 50 years.

So the Darwin Station scientist removed the only four they could find.

Fortunately, these included both the male and the female.

Eventually, two males and 11 females were collected, and the San Diego Zoo contributed another male to add to genetic variation.

The San Diego tortoise soon became the station's top ranking stud animal.

Before the young tortoises could be released to their natural habitat, the goats on Espanola had to be eliminated.

There would've been no sense in releasing young tortoises if the goats were simply going to eat all the food they needed.

Espanola is flat, with very little jagged lava, and it's only about four miles long, so getting rid of the goats there was comparatively easy.

In 1975, the first young tortoises were ready for release.

By 1985, 151 tortoises bred at the station had been returned to Espanola.

Captive breeding programs are successfully underway for subspecies from six of the islands.

To date, more than 800 tortoises have been repatriated, but there's not likely to be an immediate population explosion.

Giant tortoises not only live to a great age, but come to maturity slowly.

While the prospect is brighter for the Espanola tortoise, its future can't be secure without long-term help from the Darwin Station and the park service.

The land iguanas of the Galapagos are far worse off than the tortoise.

Their future is secure on only three of the uninhabited islands.

The colonies on Santa Cruz and Isabela, two of the inhabited islands, are in considerable danger.

They need all the help they can get from the Darwin Station.

As with the tortoises, each island has its own subspecies.

This is a Santa Cruz land iguana.

At the Darwin Station, the iguanas nest naturally, but then their eggs are removed to the safety of an incubator.

The large enclosures aren't roofed in and there's always the danger of rats or feral cats stealing the eggs.

The eggs in this nest belong to a Santa Cruz iguana.

Land iguana eggs, there can be from seven to 23 in a clutch, hatch in about three and a half months.

On both Santa Cruz and Isabela, the resident land iguanas had been decimated by feral cats and dogs.

So once again, before there to be any hope of reestablishing the colonies there, wild dogs and cats had to be brought under control.

Control operations began while the first batches of iguana eggs were hatching in the station's incubator.

[soft music] The first releases began in 1982 on Isabela and Santa Cruz.

By then, the wild dogs had largely been disposed of.

The cats are more of a problem.

They catch the very small and even the half grown releases.

So the station is experimenting to find out which age and size has the best chance of escaping the predators.

Early indications are that the program is succeeding.

Of 220 young iguanas freed on Isabela since 1982, a third barring the markings put on them by the Darwin Station have been sighted by wardens.

With luck, as many more have survived.

The Galapagos bird most in danger of extinction nests in a part of the islands the visitors seldom sees; the moist volcanic uplands.

This is the bird's breeding area, 1,000 feet up on the island of Floreana.

The endangered species is the dark-rumped or Hawaiian petrel.

It's been nearly wiped out in Hawaii.

Now it's going the same way in the Galapagos, and for the same reason: rats.

Felipe Cruz, son of one of the few farmers on Floreana, devotes much of his time to the protection of the dark-rumped petrel.

The Darwin Station welcomed Felipe's help.

Now backed by the World Wildlife Fund, he protects and studies one of the largest petrel colonies in the Galapagos.

The dark-rumped petrel is an nocturnal seabird.

It nests and crevices of lava or in earthen burrows.

Early settlers found the petrels in immense numbers.

There are still 10,000 pairs in the Galapagos, so it's hard to believe the species really is in danger.

But their numbers are falling fast due to predation by rats and cats.

Assisted by his wife, Justine, Felipe Cruz records progress in 100 nests, visiting each one once a week during the breeding season.

Dark-rumped petrels lay only one egg.

In the first year of his study, less than a third of his nests ever fledged chicks.

The next year there was some improvement; almost a half of the nests were successful.

The third year saw a great change for the better.

Three out of every four nests produced chicks to the flying stage.

The difference was that Felipe and Justine had launched an all out trapping campaign against the rats.

Even for the Cruz's who live on Floreana and are used to the conditions, the campaign was an arduous one.

Often the trails to the colony were a sea of mud.

Because of the danger to other wildlife, poison baits could only be used with great care, so hundreds of traps had to be set each day.

[dark music] [cage snaps] By the third year, predation by rats had been reduced to zero, and the main nesting colony, which the local settlers had voluntarily made a protected area, was fairly secure.

The islands offer many opportunities for research into the problems of creatures, which while not indigenous to the Galapagos, visit them to breed.

Black Turtle Cove on Santa Cruz is one such breeding ground.

Turtles are not the only species to frequent the shallows among the mangroves.

These are golden rays.

The green turtles come to the lagoon to mate, and the females leave to find a sandy beach to lay their eggs.

There are often 200 or 300 turtles in the lagoon.

Large sharks too.

Though they're never aggressive to people.

It's a unique opportunity for the Darwin Station scientists to catch turtles as part of the study that's been going on for 10 years with the help of the Nature Conservancy.

[water splashing] Green turtles are endangered the world over.

Elsewhere, their beaches are increasingly disturbed by tourism.

They're exploited throughout the tropics for their flesh and their eggs.

In the Galapagos, they are at least safe from human predation.

Here they caught two at once; a mating pair.

Despite the protection given them by the National Park, the green turtles which visit the Galapagos still have their problems.

Once again, the villain is an animal escaped from the settlements and breeding in the wild.

The pig.

On some beaches, the feral pigs dig up every single nest.

One of the purposes of the capture operation by the Darwin Station staff is to check on the sizes and probable ages of the turtles.

They also tag them so that their progress can be followed and their breeding success monitored.

Catching, measuring and marking breeding turtles is the easiest part of turtle study and protection.

The real problem is to get rid of the marauding pigs.

They breed fast and are nocturnal, so they go foraging just at the time when the female turtles are ashore laying their eggs.

They've even been seen to eat the eggs as fast as the turtle lays them.

So once again, the conservation problem is the need and difficulty of eradicating escaped domestic animals.

Another part of the study takes place on the nesting beaches between sunset and sunrise; the time when the female turtles come ashore to nest.

Tagging has revealed some disturbing facts.

It was previously thought that most female turtles made two or three nests and laid batches of 70 or 80 eggs in each during a single breeding season.

Now there's increasing evidence that up to 45% of the females nest only once in a lifetime.

So how many turtles throughout the tropics have been slaughtered before they've had a chance to breed?

Why there should be such a difference in the nesting capacity of different females is still a mystery.

This is one of the questions the scientists are researching.

As the dawn breaks, the last of the nesting females heads back to the sea, bearing a Darwin Station tag.

Tagging has shown that nearly 90% of those females which return to lay and following seasons choose exactly the same beach, almost certainly the one on which they themselves were hatched.

Recently, man has come to the Galapagos in ever increasing numbers.

Dolphins ride the bow waves of the tourist boats.

The visitors come 90 at a time on cruise ships or in small parties on chartered yachts.

Up to 20,000 visit the gala each year.

[boat engine rumbling] Only one cruise ship at a time is allowed to visit a single tourist site.

All tourist boats have guides trained by the National Park and Darwin Station.

The maximum number in any guided party is 30 people.

And all the guides have to complete a month's course and pass an examination to get a three year license.

The system is a good one, and to date, is working well.

A large percentage of tourists are Ecuadorians, but visitors come from all over the world bringing badly needed currency.

So it's understandable that there should be pressure to allow in more tourists.

At present, the limit is 25,000 a year.

Inevitably, there are moves to bring in bigger ships with the risk of garbage being jettisoned, pollution from bilge cleaning and even oil spills affecting shore life such as the marine iguanas.

There are plans to build big modern hotels, which would drastically impair the Eden-like quality of these islands.

Where tourism is concerned, the problem is a familiar one: to strike a balance between demands of conservation and the legitimate wish of ordinary people to see the natural wonders that are being conserved.

The possibility of overdevelopment is always a threat.

The other key problem is money.

Despite the revenue that the tourist ships bring, both the park and the Darwin Station are run on shoestring budgets.

Without adequate international funding for conservation, this fragile Eden, the Galapagos Islands, could to become a memory.

[soft orchestral music] [birds chirping] Charles Darwin wrote, "One is astonished at the amount of creative force displayed on these small, baron and rocky islands.

With care, the secrets of that creative force may continue to unfold."

[waves crashing] [uplifting orchestral music]