Amazing Journeys

Across the Earth, creatures begin to sense secret signals ...

begin to move.

There is change in the length of day, and of night ... in air temperature ...

and weather ... foreshadowing a great upheaval ahead.

On a planet constantly in motion, swept by relentless seasonal change,

life too must move in order to survive.

Miracles of nature are about to unfold.

Each summer an extraordinary migration is fueled by millions ...

of tiny eating machines.

Gorging themselves on milkweed, they grow large enough for transformation ...

from caterpillar ... into one of Nature's most sublime creations:

the monarch butterfly.

Generation by generation, waves of monarch butterflies will migrate ...

northward through the United States as far as southern Canada.

As many as four generations are produced each summer.

The fourth generation appears no different from those that ...

preceded it, but it is.

Instinct tells it not to mate but to accumulate fuel urgently,

loading nectar through a straw-like proboscis.

This generation will live at least eight times longer than ...

its predecessors, enabling it to complete the longest and greatest ...

insect migration on Earth ...

Using prevailing winds when possible, they labor to cover ...

about 100 miles a day.

Escaping the northern winter, they navigate toward a place ...

last visited by their great-great grandparents.

Converging from across two-thirds of North America, as many as ...

half-a-billion sweep southward toward central Mexico ...

on journeys of up to 2,500 miles.

Only one in five survives the hazards of the long migration,

but their numbers are so vast: a hundred million complete the journey ...

arriving each year in the same small patches of mountain forest ...

that ensure their survival through winter.

How something the size of a leaf, can navigate across an entire continent ...

to a place it has never been, remains an unsolved mystery of nature.

The return of the monarchs holds mystical significance.

It is the Mexican celebration of the Day of the Dead.

In cemeteries, villagers gather with incense and candles to welcome back ...

the souls of departed loved ones ...

Because the arrival of the monarchs coincides with the Day of the Dead,

many villagers believe the spirits of their loved ones are ...

returning on the wings of butterflies.

In the forest above the village, the last of the monarchs have arrived.

Through the winter they hang almost motionless in semi-dormancy.

A single tree may be blanketed by tens of thousands ...

so many featherweight creatures their combined mass can break the branches.

Their winter homes are today protected reserves ...

but to local schoolchildren they seem like magic forests.

They will fly only when warm enough.

A gentle breath is all it takes to trigger a cascade.

As spring approaches, the northward migration must begin.

It is time at last for this generation to mate.

The females lead the great exodus ... carrying their fertilized eggs ...

toward the North American heartland ...

each carrying as well the secrets of how a distant future generation ...

will finds its way back, and complete a migration ...

as mysterious and wondrous as any on Earth.

Of all nature's migrators, none travel farther ...

or in greater number than birds.

Their preparation is intense. The young of species like Canada Geese ...

must grow enough in summer to migrate with adults by autumn.

Aviation fuel in the form of fat must be packed on ...

to power the flight ahead.

Some grow so heavy they can barely take off.

But when ready, they grow restless and eager ...

Signals only they can decipher tell them when the weather ...

and winds are most favorable ...

signals that propel them irresistibly forward,

to join one of Nature's greatest spectacles.

Traveling mostly beyond our view, migratory birds have eluded our ...

understanding since earliest times.

Today, radar designed to track Aircraft and weather has begun ...

to peer into their rarely seen world.

Researchers have confirmed that most small birds migrate at night ...

and that many species save energy by riding storm winds ...

and prevailing air currents.

Radar studies have also disclosed flight speeds, travel routes ...

and flock sizes ... and revealed that birds migrate in greater numbers ...

than previously thought, over distances once unimagined.

Five billion birds migrate each year from Europe deep into Africa,

and similar throngs cross Asia and the Americas.

To find their way, birds employ a remarkable array of techniques.

Initially, instinct points them in the right direction.

Where possible they follow landmarks.

Where there are no landmarks, they turn to compasses provided by nature.

Many take their bearings from the sun's position.

The billions of night flyers seem to orient to the sunset ...

in the west as they set out.

Night offers protection from predators and smoother,

cooler air for easier flight, but somehow they must navigate ...

through the dark. Like early pilots, they simply ...

use the stars as a compass and fly toward familiar constellations.

When clouds obscure the stars, an internal magnetic compass ...

may guide them. Occasionally, the Earth's magnetic field is ...

visible to us in auroras, but only in the polar skies at night.

Some birds use a magnetically sensitive substance in their heads ...

to detect the pattern of Earth's magnetic field ... and to follow it ...

like a map in the sky.

Equipped by nature with a remarkable array of navigational skills,

using whichever best guides them moment to moment,

birds are the master navigators of the animal kingdom ...

The cold nutrient rich waters of the northern Pacific provide ...

an abundance of food for migrating sea mammals.

But when winter arrives, many leave here and swim great distances ...

to accomplish another common goal of migrations ...

to mate and give birth in places of safety and warmth.

So strong is this compulsion, gray whales make the longest migration ...

of any wild mammal ... swimming non-stop day and night without feeding ...

for up to two solid months ... from as far north as the Arctic Ocean ...

5,000 miles south to Mexico.

They may navigate through dark and murky seawater ...

using a primitive echo-location system.

Like submarines, many whales beam out and receive echoing sounds ...

that sketch acoustic images of the undersea terrain.

Traveling near shore, grays sometimes spy-hop ...

perhaps to locate familiar coastal landmarks.

They maintain their bearings simply by keeping the sound of the surf ...

to their left going south, to the right returning northward.

Pregnant females lead the migration south in order to reach ...

Mexico before giving birth.

Unfortunately, the timing is not always perfect ...

L. A. County lifeguards were the first to reach the 13-foot-long ...

infant gray whale. Experts tell us it's a female and they think she's ...

less than a week old because part of the umbilical cord is still attached.

It's said the mother may have started south late, giving birth along the way ...

to an orphan now badly dehydrated and malnourished. Rescue efforts are now ...

underway to bring the baby whale out of the water and transport her ...

to an emergency care center at "Sea World" in San Diego, two hours away.

I needed to drive as fast as I could, as fast as the truck would go ...

and I knew time was of the essence. And then the CHP would just zoom on ...

right ahead, close off traffic and let this whale go on by.

When I first saw the whale, I honestly didn't think ...

that she was alive. We see animals like this all the time,

and the majority of them come in and die very soon after,

or arrive dead.

They name her ''J.J.'', and begin round-the-clock care.

They must quickly learn how to take the place of a mother whale.

It was amazing. As soon as the warm milk reached her stomach,

she calmed ... as if she recognized that we were here to help her.

She was still semi-comatose and my assessment at the time was that ...

that animal had almost no chances of surviving. She was in very bad shape.

While J.J.'s fate resides in the hands of human keepers, most of the ...

gray whale mothers have made it to the warm, protected lagoons of ...

Baja California before giving birth.

The regularity of their migrations Once made them easy prey for whalers.

Now, they are greeted like Celebrities by adoring fans ...

yearning to touch a real whale.

Protective laws discourage boaters from approaching a whale ...

but no law prevents a whale from approaching a boat.

Naturalist Sherri Bondi and her daughter are here ...

for just such an encounter ...

My little girl, Selenita, the little mermaid, has ...

a very special connection to the whales.

When I got out there it was just like, whoa ...

One was coming straight for us and I'm like what's that whale doing?

Look it, Mommy. I ...

Oh, look at the eye, look.

They seem to really study us carefully. I often wonder ...

what they're thinking about while they're gazing at us,