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(mushroom crackling)

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- [Narrator] In just four days, Christmas will be here.

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Every day at dawn frost announces the arrival of winter

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on the inland of the Iberian Peninsula,

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and kills off the mushrooms of autumn.

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(ice crackling)

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(mysterious music)

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(gentle music)

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Life is sleeping in the trees of Spain

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and Portugal because of the cold.

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We have passed from the ochre shades

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of the leaves in the fall

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to the naked gray of the branches and leaden skies.

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Winter is here.

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The sun, when it shows its face on the days

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that it manages to pierce the clouds or the fog,

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doesn't rise very high above the horizon.

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This makes it even colder.

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And the temperatures can fall

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to minus 20 degrees Celsius in some places,

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like the Aragonese province of Teruel.

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(cranes honking)

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In December of 1963,

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the temperature reached minus 30 degrees Celsius.

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Although that doesn't scare the cranes,

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because where they come from, it's even colder.

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(cranes honking)

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(wind whooshing)

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The mountains that surround the great city of Madrid

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also awaken under a mantle of frost.

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Sierra de Guadarrama National Park is a surprising place

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with enormous masses of granite and dizzying slopes.

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It's hard to walk over the rock formations.

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known as La Pedriza,

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and nobody can run over them except for the Iberian ibex,

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which protects itself from predators

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by scrambling to the highest of these rocks.

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Beginning in November, the drop in temperatures

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leads the males to descend from the mountain peaks

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at an altitude of 2,000 meters.

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(urine trickling)

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Since the previous spring they've stayed far away

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from the females and their kids,

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but the meeting period for this very tough species

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takes place precisely when the air gets nippy again.

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The females like to make the determined males

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court them tenaciously.

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It will be a long time before they let the males mount them.

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(hooves scraping)

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What the male does with his tongue

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as he tries to convince her may look odd,

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but that's so he can use the sense organs in his mouth

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to analyze the pheromones that indicate

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at what point of ovulation each female is in.

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Many days will go by, several weeks even,

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before the big male will be accepted yet another year.

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It's essential that the production of their sexual cells

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be precisely synchronized.

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(hooves scraping)

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And she won't accept him until she's sure

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that she can be impregnated.

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It seems it's still too early for her.

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By the end of December,

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all the females will have been mounted.

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Only the strongest males, the ones with the biggest horns,

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the ones with the darkest coats,

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the toughest ones, are accepted by the females.

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The Iberian ibex's process of natural selection

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includes one of the most explosive

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and dangerous combats in the animal kingdom.

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(ominous music)

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(horns crashing) (dramatic music)

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Some of these battles can last close to an hour.

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And the most curious thing is that the ones that fight

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are actually the deputies of the big alpha males.

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In this way, the Iberian ibex avoids having to fight

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many young males, one after another,

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which might exhaust the great sultan

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and threaten his right to reproduce.

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(hooves scraping) (wind whooshing)

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But in any case,

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the females are always the ones who say yes or no.

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The Iberian Peninsula covers

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almost 600,000 square kilometers.

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15 Iberian Peninsulas would fit in the Sahara Desert

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and 10 in the Amazon River basin.

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It represents only 5% of the surface area of Europe,

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and yet the value of its wildlife

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isn't proportional to its size.

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These lands are exceptionally important

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because of their diversity

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and their geo-strategic location.

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And in the south, quite close to Africa,

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from the Algarve on the Atlantic ocean,

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to the beaches of the Mediterranean sea,

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it never freezes over.

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Africa is only an hour away as the crow flies, or even less.

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Many travelers make round trips from one world to another,

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especially in spring and autumn.

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These geese, however, arrive in winter,

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but that's because they aren't coming from the south,

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but rather from beyond the Arctic circle.

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Their food in Scandinavia is frozen now.

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and they've come in search of chufa sedges,

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an aquatic plant that grows in shallow waters.

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The root of the chufa sedge is very tough

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and a little sand in your gizzard

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comes in really handy to digest it.

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The sand from the dunes in Donana

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will help the geese with the job.

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(geese honking)

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In winter the geese gather together in huge flocks

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of up to tens of thousands of birds.

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Only very specific and very rich ecosystems

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can sustain them, such as the wetlands

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of the Guadalquivir River,

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the mouth of the Tagus River south of Lisbon,

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or the lakes of Villafafila in Zamora province.

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(bright music)
(geese honking)

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This cold region of Spain

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must remind them of their northern home

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because they receive the low temperatures

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like an old friend.

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At nightfall the geese seek refuge in the water

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to sleep safe from the wolves, foxes, and wild boar.

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(geese honking)

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But at night and during the early dawn hours,

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from December to February,

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these shallow waters freeze over.

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(mischievous music)

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That is, unless thousands of geese

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are continuously paddling with their feet,

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preventing ice from forming and trapping them.

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That's why the water in the area along the shore

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where the geese have slept

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isn't covered with a hard sheet of ice

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like the rest of the lake.

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The temperature of the water is below freezing,

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but by moving their legs, the flock has kept it liquid.

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Their plumage, oiled and appropriately combed,

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is the perfect insulation

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to prevent their skin from coming in contact

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with the water or the air.

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Their legs minimize the blood flow

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so the loss of body heat is minimal.

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This species is perfectly adapted

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to winter's low temperature.

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(mischievous music) (geese honking)

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(wind whooshing)

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In the Pyrenees winter is always white

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and freezing cold.

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But the blood of the ravens is boiling

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in the depths of January,

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at an altitude of more than 3,000 meters.

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The ravens have chosen to fly over the windiest

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and most difficult peak today,

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because it's time to show the rest

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just what each one of them is made of.

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(ravens cawing)

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The flocks of ravens band together in winter

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to perform acrobatic tricks.

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These aren't mere practice runs.

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Their dive bombing and loop-de-loops are risky.

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Flying so close to each other, at high speed,

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with strong gusts of cross winds and low visibility,

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increases the likelihood of their losing control.

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And just a slight sprain,

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a twisted wing, would mean sure death up here.

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(dramatic music)

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There's no doubt that these birds' intellectual capacity

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allows them to enjoy this game.

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And they do, with any object.

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They have fun taking it away from each other,

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but the ultimate aim isn't playful.

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The pairs are synchronizing their biological clocks

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and strengthening their emotional bonds.

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Almost all of them will end up finding a mate,

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although they aren't looking for the best bird,

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or the strongest one or the bravest one,

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but rather for the best match,

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the bird that they synchronize with well.

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(gentle music)

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In many parts of the Iberian Peninsula,

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the winter cold and snow complicate the efforts

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to get food each day.

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It's the time of year that produces the first deaths,

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discarding the extra animals

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that were born the previous spring.

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(dramatic music)

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(dramatic music ends)

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(birds chirping)

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As the cold approaches,

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the starling's social behavior changes radically.

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In the spring they raised their chicks

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while living in isolated pairs.

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And then during the autumn, they gradually joined

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their neighbors in small groups to feed.

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Now in winter, they gather together

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in large flocks to sleep,

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sometimes in flocks numbering in the millions.

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The idea is for the younger starlings

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to occupy the outer areas of the flock on the perimeter,

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which is the most dangerous area

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because that's where predators attack.

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The most experienced starlings almost always

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fly in the center of the flock,

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where they are protected by the insurmountable shield

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formed by so many unseasoned rookies.

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In exchange for risking their lives,

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these young starlings learn how to fly better.

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And above all, where they have to look for food

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and shelter at nightfall.

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Each of the last three days at dusk,

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they've been attacked by two sparrowhawks

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when they had settled in the branches to roost.

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And in the air by a Peregrine falcon.

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That's the only bird able to beat them up above.

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(melancholic music)

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But three casualties a day among a population

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of three million isn't a significant loss.

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And besides, statistically, they must've been

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the individuals that didn't know how to move in sync

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in that same split second as the other members

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of their squadron.

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But thanks to that culling,

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each year the flocks of starlings fly better.

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(majestic music)

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(wind whooshing)

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By mid-January, the period of hibernation

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has entered the toughest phase.

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Underground, buried inside tree trunks,

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or submerged in freezing cold water,

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many living beings lie in wait,

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their lives temporarily on hold.

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A good number of them will never wake up again.

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Hibernation isn't easy.

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The most common frog on the Iberian Peninsula,

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Perez's frog, is one of the amphibians best prepared

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to withstand low temperatures, even freezing.

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If ice crystals form inside a living organism,

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they cause irreparable damage

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that almost always leads to death.

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The water dissolved in the cells enlarges when it freezes

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and breaks the cell membranes and walls.

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The animals that have to survive extreme temperatures

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while hibernating have substances

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that protect them from freezing,

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and that limit the increase in volume of each cell.

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even if it freezes.

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This is an essential adaptation that both invertebrates

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and vertebrates have developed

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so that they can hibernate without dying.

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(wind gusting)

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Hibernation is an excellent strategy.

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A process to isolate one's self

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from the harsh continental climate

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or the severe weather in the high mountains,

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which prevent many animals from getting food

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or even digesting it.

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It's effective because the cold keeps an animal's

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body temperature very low while it sleeps.

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And so it minimizes energy consumption to practically zero.

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(birds chirping)

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If the sun gets a little warmer for a few days,

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it allows some hibernating animals to wake up

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and move around a bit,

267
00:23:06,670 --> 00:23:09,687
even go out for a short walk or drink a little.

268
00:23:11,090 --> 00:23:13,120
But that scant heat isn't enough

269
00:23:13,120 --> 00:23:15,203
to carry out metabolic processes.

270
00:23:16,570 --> 00:23:18,903
So they have to go back to sleep again.

271
00:23:36,700 --> 00:23:39,520
Birds don't know how to hibernate,

272
00:23:39,520 --> 00:23:42,520
and besides in the southwest of the peninsula,

273
00:23:42,520 --> 00:23:44,990
near the border between Spain and Portugal,

274
00:23:44,990 --> 00:23:47,393
it gets cold, but not very.

275
00:23:53,750 --> 00:23:56,690
The griffon vultures have begun to fly in pairs

276
00:23:58,440 --> 00:24:01,963
and the male and female follow each other for hours.

277
00:24:15,980 --> 00:24:19,370
When they take a break, they try out different rocks

278
00:24:19,370 --> 00:24:20,960
to choose the one they like best

279
00:24:20,960 --> 00:24:23,193
for the platform for their future nest.

280
00:24:39,220 --> 00:24:42,650
The Salto del Gitano, one of the most emblematic places

281
00:24:42,650 --> 00:24:45,300
in Spain's Monfrague National Park,

282
00:24:45,300 --> 00:24:47,350
is the site of one of the largest colonies

283
00:24:47,350 --> 00:24:49,313
of this species in the world.

284
00:25:07,030 --> 00:25:09,890
The population of griffon vultures was declining

285
00:25:09,890 --> 00:25:12,350
until only a few decades ago,

286
00:25:12,350 --> 00:25:14,560
but now they're bouncing back

287
00:25:14,560 --> 00:25:17,393
and bringing balance back to the countryside.

288
00:25:34,940 --> 00:25:38,450
Nobody hibernates on the southern coast of Iberia.

289
00:25:38,450 --> 00:25:41,060
Here, during the worst period of the year,

290
00:25:41,060 --> 00:25:43,000
the skies get a little cloudy

291
00:25:43,000 --> 00:25:44,610
and at most the temperatures drop

292
00:25:44,610 --> 00:25:47,140
to five or 10 degrees Celsius,

293
00:25:47,140 --> 00:25:49,453
but the weather doesn't get truly cold.

294
00:25:51,870 --> 00:25:55,710
Although there are fewer insects and fewer arthropods,

295
00:25:55,710 --> 00:25:58,123
like the brine shrimp that flamingos feed on.

296
00:25:59,720 --> 00:26:01,813
That forces them to spread out.

297
00:26:05,440 --> 00:26:08,350
To find their food they have to stir up the mud

298
00:26:08,350 --> 00:26:11,100
with their feet, stamping their feet

299
00:26:11,100 --> 00:26:12,750
as if they were dancing flamenco.

300
00:26:13,915 --> 00:26:18,915
(bright flamenco music) (man vocalizing)

301
00:27:11,370 --> 00:27:13,500
The lukewarm southwesterly winds

302
00:27:13,500 --> 00:27:15,763
help the flamingos to fly home again,

303
00:27:16,740 --> 00:27:19,120
and also sweep a lot of African sand

304
00:27:19,120 --> 00:27:20,513
to the wetlands of Donana,

305
00:27:22,130 --> 00:27:26,283
creating an ecosystem of sand dunes that is very rare.

306
00:27:31,800 --> 00:27:33,500
The plant species that have adapted

307
00:27:33,500 --> 00:27:35,210
to this type of substrate,

308
00:27:35,210 --> 00:27:38,780
with hardly any moisture and very few nutrients,

309
00:27:38,780 --> 00:27:41,380
create a barrier of stems and roots

310
00:27:41,380 --> 00:27:43,363
that holds the sand in place a little.

311
00:27:44,310 --> 00:27:46,873
That's what gradually forms each dune.

312
00:27:48,400 --> 00:27:51,913
But sand is like a liquid and can't sit still.

313
00:27:53,290 --> 00:27:54,653
Dunes move.

314
00:27:56,900 --> 00:28:00,400
Nothing can keep them from advancing completely,

315
00:28:00,400 --> 00:28:03,983
at a speed that ranges from three to six meters a year.

316
00:28:08,470 --> 00:28:10,690
That's very slow movement,

317
00:28:10,690 --> 00:28:13,140
but eventually they will reach the marshes

318
00:28:13,140 --> 00:28:15,963
and will sink into them and disappear.

319
00:28:18,190 --> 00:28:20,500
In rainy years, the force of the water

320
00:28:20,500 --> 00:28:24,620
will sweep the sand away and carry it back to the sea,

321
00:28:24,620 --> 00:28:25,933
closing the circle.

322
00:28:26,810 --> 00:28:28,060
But on their journey,

323
00:28:28,060 --> 00:28:30,723
the dunes kill everything in their path.

324
00:28:32,570 --> 00:28:35,740
They line up like the waves on the sea.

325
00:28:35,740 --> 00:28:38,573
Here there are six main lines of dunes.

326
00:28:40,750 --> 00:28:43,440
The vegetation finds a place to live in the space

327
00:28:43,440 --> 00:28:45,870
between each line of dunes,

328
00:28:45,870 --> 00:28:48,243
but only for a limited period of time,

329
00:28:52,230 --> 00:28:56,253
Stone pines manage to form magnificent thick forests,

330
00:28:57,320 --> 00:29:00,690
but the moving dunes eventually surround them

331
00:29:00,690 --> 00:29:03,192
and gradually bury them all.

332
00:29:03,192 --> 00:29:06,192
(suspenseful music)

333
00:29:10,970 --> 00:29:12,343
Or almost all.

334
00:29:14,080 --> 00:29:18,430
Every once in awhile, a pine tree sprouts in the right spot

335
00:29:18,430 --> 00:29:21,900
or grows a little faster and taller than the rest.

336
00:29:21,900 --> 00:29:23,710
And it isn't smothered to death

337
00:29:23,710 --> 00:29:26,923
because the sand can't quite cover it completely.

338
00:29:28,060 --> 00:29:29,930
That's the exception,

339
00:29:29,930 --> 00:29:32,270
the witness to the dunes' passage,

340
00:29:32,270 --> 00:29:35,683
and perhaps the future of a new species of stone pines.

341
00:29:37,883 --> 00:29:40,466
(wind gusting)

342
00:29:47,750 --> 00:29:50,330
Wetlands and marshes are ecosystems

343
00:29:50,330 --> 00:29:52,563
where biodiversity concentrates.

344
00:29:54,440 --> 00:29:57,673
This is especially evident with respect to waterbirds.

345
00:29:59,540 --> 00:30:01,870
There are a lot of waterbirds here

346
00:30:01,870 --> 00:30:05,260
and a great variety of species of waterbirds.

347
00:30:05,260 --> 00:30:08,930
And if there are birds than there are fish and invertebrates

348
00:30:08,930 --> 00:30:11,433
and vegetation and predators.

349
00:30:12,670 --> 00:30:15,943
The role of these valuable wet habitats is crucial.

350
00:30:18,880 --> 00:30:22,660
The marshes of Santona, the mouth of the Tagus River,

351
00:30:22,660 --> 00:30:25,983
the Ebro River delta, the wetlands of Donana or Daimiel.

352
00:30:26,860 --> 00:30:29,220
These are perhaps the most important ones,

353
00:30:29,220 --> 00:30:31,660
both for native species,

354
00:30:31,660 --> 00:30:33,830
and for the migratory species that use them

355
00:30:33,830 --> 00:30:37,123
as places to rest and feed on their journeys.

356
00:30:41,610 --> 00:30:44,780
Certain duck species even spend whole seasons here

357
00:30:44,780 --> 00:30:46,690
when the climate in their countries of origin

358
00:30:46,690 --> 00:30:47,893
is inhospitable.

359
00:30:52,320 --> 00:30:55,453
Now the birds that winter in Iberia are numerous.

360
00:30:59,660 --> 00:31:01,400
Although at this time of year

361
00:31:01,400 --> 00:31:03,133
they may not be visible every day.

362
00:31:04,140 --> 00:31:07,010
Frequently the bad weather forces them to seek shelter

363
00:31:07,010 --> 00:31:09,280
among the reeds and bulrushes.

364
00:31:09,280 --> 00:31:11,423
And the landscape looks empty.

365
00:31:31,354 --> 00:31:33,937
(wind gusting)

366
00:31:43,930 --> 00:31:46,440
The presence of wolves is becoming normal again

367
00:31:46,440 --> 00:31:49,259
in the northwestern half of Iberia.

368
00:31:49,259 --> 00:31:52,092
(wolves snarling)

369
00:31:54,230 --> 00:31:56,730
Perhaps where they are most abundant

370
00:31:56,730 --> 00:32:01,260
is from Montesinho Natural Park to Peneda-Geres,

371
00:32:01,260 --> 00:32:03,623
the only national park in Portugal.

372
00:32:08,124 --> 00:32:10,874
(wolves howling)

373
00:32:18,990 --> 00:32:21,890
Every day these populations cross the border

374
00:32:21,890 --> 00:32:23,760
between Spain and Portugal,

375
00:32:23,760 --> 00:32:26,220
heading for the Sierra de la Culebra mountain range,

376
00:32:26,220 --> 00:32:29,230
and even reaching the Ancares range in Galicia,

377
00:32:29,230 --> 00:32:31,320
crossing and strengthening their genes

378
00:32:31,320 --> 00:32:32,673
and their bloodlines.

379
00:32:37,820 --> 00:32:40,753
The protection of these lands is proving successful,

380
00:32:41,950 --> 00:32:45,440
and an ecosystem where an apex predator can reproduce

381
00:32:45,440 --> 00:32:47,193
is a healthy ecosystem.

382
00:32:57,120 --> 00:33:00,440
Likewise, the Iberian Wolf is also colonizing

383
00:33:00,440 --> 00:33:03,343
its old territory south of the Douro River again.

384
00:33:05,170 --> 00:33:07,380
It has even reached the mountains in the center

385
00:33:07,380 --> 00:33:09,473
of the peninsula, near Madrid.

386
00:33:12,450 --> 00:33:15,320
The cold winter nights once again bear witness

387
00:33:15,320 --> 00:33:17,380
to the sounds of the new packs

388
00:33:17,380 --> 00:33:20,174
reclaiming the lands that they used to roam

389
00:33:20,174 --> 00:33:22,498
and organizing themselves to hunt.

390
00:33:22,498 --> 00:33:25,248
(wolves howling)

391
00:33:47,030 --> 00:33:49,410
Although March is almost here,

392
00:33:49,410 --> 00:33:51,810
last night was the coldest night of the year

393
00:33:51,810 --> 00:33:53,700
in the forests of Valsain

394
00:33:53,700 --> 00:33:55,550
in the Central mountain range,

395
00:33:55,550 --> 00:33:58,303
at an altitude of almost 2,000 meters.

396
00:34:00,480 --> 00:34:02,683
The sharp pine needles are tough,

397
00:34:04,340 --> 00:34:06,083
like the spines of a cactus,

398
00:34:07,880 --> 00:34:09,830
and the leaves of these trees

399
00:34:09,830 --> 00:34:13,663
can bear both searing heat and bitter cold.

400
00:34:14,590 --> 00:34:18,500
In reality, almost everything in this land of extremes

401
00:34:18,500 --> 00:34:20,230
is prepared to survive temperatures

402
00:34:20,230 --> 00:34:23,550
ranging from the minus 20 degrees Celsius now

403
00:34:23,550 --> 00:34:25,763
to more than 30 degrees in summer.

404
00:34:30,180 --> 00:34:34,423
That's an atmospheric temperature range of 50 degrees.

405
00:34:45,090 --> 00:34:48,780
150 kilometers farther south, as the crow flies,

406
00:34:48,780 --> 00:34:53,770
in Cabaneros, the land has also suffered a severe frost.

407
00:34:53,770 --> 00:34:56,893
The cold takes the lives of many of the animals here.

408
00:34:59,450 --> 00:35:01,633
This red deer couldn't withstand it.

409
00:35:03,020 --> 00:35:05,170
But it also favors the natural selection

410
00:35:05,170 --> 00:35:07,233
of the best adapted individuals.

411
00:35:08,290 --> 00:35:11,520
This fox is taking full advantage of the opportunities

412
00:35:11,520 --> 00:35:13,630
that luck has offered it.

413
00:35:13,630 --> 00:35:16,950
Foxes are hunters, but like almost all predators,

414
00:35:16,950 --> 00:35:19,503
they don't turn their noses up at good carrion.

415
00:35:25,860 --> 00:35:28,640
But the vultures have already discovered it

416
00:35:28,640 --> 00:35:31,310
and are in no mood to share.

417
00:35:31,310 --> 00:35:34,463
Nobody here would dare to confront so many vultures.

418
00:35:39,456 --> 00:35:41,860
The griffon vultures of the Iberian Peninsula

419
00:35:41,860 --> 00:35:45,203
have no trouble finding food in either cold or hot weather.

420
00:35:46,820 --> 00:35:49,463
Somebody is always dying for them.

421
00:35:52,800 --> 00:35:55,330
This species was threatened with extinction here

422
00:35:55,330 --> 00:35:57,440
only a few decades ago,

423
00:35:57,440 --> 00:36:00,383
but now its population has bounced back.

424
00:36:03,430 --> 00:36:06,300
The griffon vultures are now beginning to choose mates

425
00:36:06,300 --> 00:36:07,963
and getting ready to raise young.

426
00:36:08,860 --> 00:36:11,670
The females are about to lay eggs.

427
00:36:11,670 --> 00:36:14,190
And their needs and hunger are greater

428
00:36:14,190 --> 00:36:16,850
than at any other time of the year,

429
00:36:16,850 --> 00:36:19,553
and that's why they're fiercer, too.

430
00:36:19,553 --> 00:36:22,720
(vultures squabbling)

431
00:36:37,960 --> 00:36:40,050
Eurasian eagle-owls raise their young

432
00:36:40,050 --> 00:36:42,460
in the worst of the cold weather.

433
00:36:42,460 --> 00:36:44,790
Even earlier than vultures.

434
00:36:44,790 --> 00:36:47,470
These chicks were born a few weeks ago,

435
00:36:47,470 --> 00:36:50,843
but some even broke through their shells in January.

436
00:36:54,140 --> 00:36:58,500
Rodents, rabbits, even foxes and the occasional kite,

437
00:36:58,500 --> 00:37:00,830
are prey that are always present in the nests

438
00:37:00,830 --> 00:37:04,003
of one of the world's largest nocturnal birds of prey.

439
00:37:07,100 --> 00:37:09,970
Owls, like all apex predators,

440
00:37:09,970 --> 00:37:12,380
help to keep the gene pool of their prey

441
00:37:12,380 --> 00:37:13,853
healthy and balanced.

442
00:37:18,230 --> 00:37:22,040
They hunt at night, making the most of the opportunities

443
00:37:22,040 --> 00:37:24,363
that they perceive with their sharp eyes,

444
00:37:26,660 --> 00:37:28,803
when no one else can see a thing.

445
00:37:38,644 --> 00:37:41,561
(wings fluttering)

446
00:37:49,087 --> 00:37:52,004
(rabbit squeaking)

447
00:38:16,180 --> 00:38:18,840
Today dawn is breaking in Iberia

448
00:38:18,840 --> 00:38:20,653
a little earlier than yesterday.

449
00:38:22,960 --> 00:38:26,500
In southern Aragon, tens of thousands of cranes,

450
00:38:26,500 --> 00:38:30,020
like the geese, are hiding in the water during the night,

451
00:38:30,020 --> 00:38:32,720
where they trust they won't be attacked by carnivores.

452
00:38:41,610 --> 00:38:44,433
The cold is still reluctant to leave,

453
00:38:45,340 --> 00:38:48,853
although it's weaker now and has little time left.

454
00:38:50,350 --> 00:38:53,600
The March equinox is just around the corner,

455
00:38:53,600 --> 00:38:56,470
and the cranes are waiting for a thermal sign

456
00:38:56,470 --> 00:38:58,308
to begin the trip home.

457
00:38:58,308 --> 00:39:01,480
(cranes squawking)

458
00:39:01,480 --> 00:39:03,273
But the sign hasn't appeared yet.

459
00:39:11,390 --> 00:39:13,640
This morning brought a very thick fog

460
00:39:16,100 --> 00:39:19,653
and the drops of water are sticking to everything,

461
00:39:21,010 --> 00:39:24,698
but the sunlight is growing warmer and warmer.

462
00:39:24,698 --> 00:39:27,281
(gentle music)

463
00:39:43,260 --> 00:39:47,863
The nights are growing shorter and the cold is less intense.

464
00:39:50,160 --> 00:39:54,050
Today the water hasn't frozen as it had been freezing

465
00:39:54,050 --> 00:39:56,240
in many rivers and lakes in the interior

466
00:39:56,240 --> 00:39:57,913
of the Iberian Peninsula.

467
00:40:00,930 --> 00:40:04,160
In winter, radiation fog is produced

468
00:40:04,160 --> 00:40:07,220
by the heat lost by the soil and water during the night

469
00:40:09,040 --> 00:40:12,350
and rises in the form of tiny water particles

470
00:40:12,350 --> 00:40:14,523
that remain suspended in the air.

471
00:40:18,360 --> 00:40:21,740
In the twilight between the darkness and the day,

472
00:40:21,740 --> 00:40:24,880
a faint light envelopes the water vapor

473
00:40:24,880 --> 00:40:26,890
before the bright sunlight makes it possible

474
00:40:26,890 --> 00:40:30,563
to see everything and everyone clearly.

475
00:40:33,870 --> 00:40:37,120
This is the time of day that many hunters prefer

476
00:40:37,120 --> 00:40:39,420
because they have a greater chance of success.

477
00:40:42,330 --> 00:40:45,303
Now is when there is a greater chance of seeing an otter.

478
00:40:52,490 --> 00:40:55,790
The conservation efforts made in Spain and Portugal

479
00:40:55,790 --> 00:40:58,120
aimed at cleaning up and improving the condition

480
00:40:58,120 --> 00:41:00,490
of the rivers and lakes has allowed

481
00:41:00,490 --> 00:41:03,273
this emblematic species to proliferate again.

482
00:41:05,040 --> 00:41:08,210
From Galicia to Andalusia,

483
00:41:08,210 --> 00:41:10,433
and from the Alentejo to the Pyrenees,

484
00:41:11,520 --> 00:41:14,473
wherever there are crayfish, fish, and amphibians.

485
00:41:26,938 --> 00:41:29,688
(toads croaking)

486
00:41:39,320 --> 00:41:42,330
Many amphibians find the weather conditions in February

487
00:41:42,330 --> 00:41:44,883
and early March favorable for reproduction.

488
00:41:49,390 --> 00:41:52,510
But in these lands, even in winter,

489
00:41:52,510 --> 00:41:55,500
milder days frequently pop up

490
00:41:55,500 --> 00:41:57,790
and that allows the natterjack toads,

491
00:41:57,790 --> 00:42:00,343
among others, to start singing.

492
00:42:06,670 --> 00:42:10,000
The water temperature is crucial for their tone of voice

493
00:42:10,000 --> 00:42:12,073
because it affects their vocal chords.

494
00:42:14,500 --> 00:42:16,380
The sounds that the males make

495
00:42:16,380 --> 00:42:18,633
attract females according to the timbre.

496
00:42:20,240 --> 00:42:22,910
For them the ideal thing is for the water

497
00:42:22,910 --> 00:42:25,643
to be at about nine degrees Celsius.

498
00:42:29,670 --> 00:42:31,610
The amphibian orgy takes place

499
00:42:31,610 --> 00:42:34,050
in a very short period of time,

500
00:42:34,050 --> 00:42:35,610
and depending on the weather,

501
00:42:35,610 --> 00:42:38,423
each body of water has its own special day.

502
00:42:39,490 --> 00:42:43,440
In most toad populations, 90% of the mating occurs

503
00:42:43,440 --> 00:42:47,263
in just a few hours on the same day, or two days.

504
00:42:52,530 --> 00:42:56,343
Some toad copulations last up to 20 hours.

505
00:42:57,890 --> 00:43:01,430
Although the hardest part isn't lasting that long,

506
00:43:01,430 --> 00:43:04,830
but rather not being able to keep hugging each other

507
00:43:04,830 --> 00:43:06,950
while being pestered by all the males

508
00:43:06,950 --> 00:43:09,713
that didn't find a mate at the start of the evening.

509
00:43:12,530 --> 00:43:14,803
And there are more males than females,

510
00:43:16,070 --> 00:43:18,623
sometimes 20 times more.

511
00:43:25,340 --> 00:43:28,073
Many of them will never reproduce.

512
00:43:33,740 --> 00:43:36,530
This one is desperately trying to break up

513
00:43:36,530 --> 00:43:38,633
the sexual grip of a mating couple.

514
00:43:40,920 --> 00:43:44,250
But it's almost impossible to undo their copulation

515
00:43:44,250 --> 00:43:47,010
once the fertilization process has begun.

516
00:43:47,010 --> 00:43:49,923
(toad grunting)

517
00:43:49,923 --> 00:43:52,673
(water sloshing)

518
00:44:01,990 --> 00:44:04,130
It would have to break the arms of the male

519
00:44:04,130 --> 00:44:06,783
that legitimately earned the right to procreate.

520
00:44:07,822 --> 00:44:10,572
(toads croaking)

521
00:44:25,940 --> 00:44:28,660
Amphibians don't usually wait for springtime

522
00:44:28,660 --> 00:44:31,363
to fulfill the task of multiplying their number.

523
00:44:32,630 --> 00:44:35,130
They, and especially their tadpoles,

524
00:44:35,130 --> 00:44:37,140
depend on the water not evaporating

525
00:44:37,140 --> 00:44:40,030
or soaking into the ground too soon,

526
00:44:40,030 --> 00:44:43,520
and sometimes spring arrives dry and hot,

527
00:44:43,520 --> 00:44:45,943
which can be a death trap for their offspring.

528
00:44:50,630 --> 00:44:52,590
But this time the development processes

529
00:44:52,590 --> 00:44:53,993
seem to be going well.

530
00:44:56,710 --> 00:44:59,923
And the worst freezes are over by this time in March.

531
00:45:02,340 --> 00:45:05,803
The pollywogs will have to hurry up and grow up.

532
00:45:29,160 --> 00:45:31,760
The griffon vultures in the southern mountain ranges,

533
00:45:31,760 --> 00:45:34,120
from Cazorla to the Sierra Morena,

534
00:45:34,120 --> 00:45:36,660
and also in Monfrague National Park,

535
00:45:36,660 --> 00:45:39,620
have noticed the changes in the air.

536
00:45:39,620 --> 00:45:42,463
Their hormones have set their nerves on end.

537
00:45:45,160 --> 00:45:49,620
The best concealed nests, the ones in the best places,

538
00:45:49,620 --> 00:45:52,530
the ones on the flattest spots,

539
00:45:52,530 --> 00:45:54,990
the ones on the steepest cliffs,

540
00:45:54,990 --> 00:45:59,146
or the easiest ones to reach are fiercely defended.

541
00:45:59,146 --> 00:46:01,896
(birds chirping)

542
00:46:14,040 --> 00:46:17,140
There aren't very many places to choose from,

543
00:46:17,140 --> 00:46:19,530
and the difference between a sheltered nest

544
00:46:19,530 --> 00:46:22,350
or one that's big enough or one that's stable,

545
00:46:22,350 --> 00:46:24,130
and one that's not,

546
00:46:24,130 --> 00:46:26,793
is decisive for the survival of each chick.

547
00:46:29,430 --> 00:46:31,793
The first few have already hatched.

548
00:46:35,410 --> 00:46:39,690
They're the riskiest bets, but if they survive,

549
00:46:39,690 --> 00:46:42,623
they'll have a big lead on the rest of the colony.

550
00:46:45,790 --> 00:46:47,410
They'll have to be ready to fly

551
00:46:47,410 --> 00:46:49,423
when summer and the heat arrive,

552
00:46:50,830 --> 00:46:53,640
when many animals will die of thirst,

553
00:46:53,640 --> 00:46:56,293
to feed the next generation of vultures.

554
00:46:57,370 --> 00:47:00,120
(birds chirping)

555
00:47:30,161 --> 00:47:33,078
(cranes squawking)

556
00:47:40,090 --> 00:47:41,970
The ice that so often made it hard

557
00:47:41,970 --> 00:47:44,603
for the cranes to drink is thinner today.

558
00:47:46,680 --> 00:47:49,963
That's another sign that everything will change soon.

559
00:47:54,360 --> 00:47:58,820
These cranes breed in the north, from Sweden to Russia,

560
00:47:58,820 --> 00:48:00,640
where they came from in autumn

561
00:48:00,640 --> 00:48:02,540
and where they have to return to nest.

562
00:48:03,439 --> 00:48:06,356
(cranes squawking)

563
00:48:33,400 --> 00:48:36,870
The first signs of the reproductive anxiety of these birds

564
00:48:36,870 --> 00:48:40,103
make it clear that everything is finally warming up.

565
00:48:40,940 --> 00:48:43,502
A few seem to be crazily happy.

566
00:48:43,502 --> 00:48:46,560
(mischievous music)

567
00:48:46,560 --> 00:48:49,763
Their ritual dances form the first mating pairs.

568
00:48:50,660 --> 00:48:52,693
They may make the return trip together.

569
00:48:55,150 --> 00:48:57,350
But just in case, it's a good idea

570
00:48:57,350 --> 00:49:00,220
to get to know each other little by little,

571
00:49:00,220 --> 00:49:02,470
because when spring makes its appearance,

572
00:49:02,470 --> 00:49:03,783
it's time for them to go.

573
00:49:53,844 --> 00:49:56,761
(cranes squawking)

574
00:50:02,030 --> 00:50:06,080
Today is the 21st of March. Spring.

575
00:50:06,080 --> 00:50:07,973
Not one crane is left.

576
00:50:09,620 --> 00:50:12,323
Theoretically, the coming months are a little nutty;

577
00:50:13,600 --> 00:50:17,320
changing weather, unpredictable behavior,

578
00:50:17,320 --> 00:50:21,163
urgency to be born, to eat, to survive.

579
00:50:23,030 --> 00:50:26,060
It's the start of a new cycle that kicks off

580
00:50:26,060 --> 00:50:28,593
when the plant kingdom and its flowers awaken.

581
00:50:30,800 --> 00:50:35,665
It's time for sex, risks, and beginning anew.

582
00:50:35,665 --> 00:50:38,415
(dramatic music)

583
00:50:44,460 --> 00:50:47,210
(majestic music)

584
00:00:01,037 --> 00:00:04,120
（蘑菇脆皮）

585
00:00:14,380 --> 00:00:17,280
- [旁白]还有四天，圣诞节就要到了。

586
00:00:20,262 --> 00:00:23,470
每天黎明的霜冻宣告冬天的到来

587
00:00:23,470 --> 00:00:26,520
在伊比利半岛内陆，

588
00:00:26,520 --> 00:00:28,947
并杀死秋天的蘑菇。

589
00:00:31,515 --> 00:00:34,710
（冰劈啪声）

590
00:00:34,710 --> 00:00:37,627
（神秘音乐）

591
00:00:49,259 --> 00:00:51,842
（轻柔音乐）

592
00:01:03,860 --> 00:01:05,780
生命在西班牙的树林里沉睡

593
00:01:05,780 --> 00:01:07,430
以及葡萄牙，因为天气寒冷。

594
00:01:09,620 --> 00:01:11,250
我们已经从赭石色阴影中走出来

595
00:01:11,250 --> 00:01:13,200
秋天的落叶

596
00:01:13,200 --> 00:01:16,473
光秃的灰色树枝和铅灰色的天空。

597
00:01:25,770 --> 00:01:26,983
冬天来了。

598
00:01:28,440 --> 00:01:30,910
太阳在白天露出脸庞的时候

599
00:01:30,910 --> 00:01:34,060
它能够穿透云层或雾气，

600
00:01:34,060 --> 00:01:36,653
离地平线不太高。

601
00:01:38,210 --> 00:01:40,280
这让天气变得更加寒冷。

602
00:01:40,280 --> 00:01:41,530
气温可能会下降

603
00:01:41,530 --> 00:01:44,630
部份地区气温降至零下廿度，

604
00:01:44,630 --> 00:01:47,017
例如阿拉贡的特鲁埃尔省。

605
00:01:48,270 --> 00:01:51,020
（鹤鸣）

606
00:01:54,060 --> 00:01:56,810
一九六三年十二月，

607
00:01:56,810 --> 00:02:00,423
气温达到零下卅度。

608
00:02:02,800 --> 00:02:05,210
虽然这不会吓到鹤，

609
00:02:05,210 --> 00:02:08,147
因为它们的来源地更加寒冷。

610
00:02:10,361 --> 00:02:13,111
（鹤鸣）

611
00:02:14,904 --> 00:02:17,654
（风呼啸）

612
00:02:31,450 --> 00:02:34,460
环绕马德里大城的山脉

613
00:02:34,460 --> 00:02:36,943
也在冰霜的覆盖下醒来。

614
00:02:39,400 --> 00:02:44,380
瓜达拉马山脉国家公园是一个令人惊讶的地方

615
00:02:46,720 --> 00:02:50,823
有着巨大的花岗岩和令人眩晕的山坡。

616
00:02:52,570 --> 00:02:54,850
走过岩层很困难。

617
00:02:54,850 --> 00:02:56,440
被称为“La Pedriza”，

618
00:02:56,440 --> 00:03:00,793
除了伊比利亚野山羊，没有人能踩过它们，

619
00:03:03,080 --> 00:03:05,250
保护自己免受掠食者的伤害

620
00:03:05,250 --> 00:03:07,993
爬到这些岩石中最高的部份。

621
00:03:10,410 --> 00:03:13,210
从十一月开始，气温下降

622
00:03:13,210 --> 00:03:16,370
带领雄性从山峰上下来

623
00:03:16,370 --> 00:03:18,993
海拔两千公尺。

624
00:03:20,968 --> 00:03:23,801
（尿液滴落）

625
00:03:29,110 --> 00:03:32,140
自去年春天以来，它们就远离了

626
00:03:32,140 --> 00:03:34,033
来自雌性和它们的孩子，

627
00:03:35,380 --> 00:03:38,540
但对于这种非常坚韧的物种来说，相遇的时间

628
00:03:38,540 --> 00:03:42,233
就在空气再次变得寒冷时发生。

629
00:03:45,070 --> 00:03:47,530
雌性喜欢让雄性坚定

630
00:03:47,530 --> 00:03:49,123
坚持不懈地追求它们。

631
00:03:50,360 --> 00:03:53,533
它们需要花很长时间才能让雄性骑上它们。

632
00:03:56,173 --> 00:03:59,006
（马蹄刮擦声）

633
00:04:10,040 --> 00:04:11,700
雄性用舌头做什么

634
00:04:11,700 --> 00:04:15,010
当它试图说服它看起来可能很奇怪时，

635
00:04:15,010 --> 00:04:18,170
但这样它就可以使用嘴里的感觉器官

636
00:04:18,170 --> 00:04:20,720
分析表明

637
00:04:20,720 --> 00:04:23,333
每个雌性动物处于排卵期的哪个阶段。

638
00:04:33,800 --> 00:04:36,910
很多天过去了，甚至几个星期过去了，

639
00:04:36,910 --> 00:04:40,063
然后再过一年，雄性才会被接受。

640
00:04:41,890 --> 00:04:44,550
性细胞的产生至关重要

641
00:04:44,550 --> 00:04:47,429
精确同步。

642
00:04:47,429 --> 00:04:50,262
（马蹄刮擦声）

643
00:04:56,640 --> 00:04:59,330
它不会接受它，除非它确定

644
00:04:59,330 --> 00:05:00,853
它就能怀孕。

645
00:05:04,320 --> 00:05:07,033
对于它来说似乎还太早。

646
00:05:11,760 --> 00:05:13,440
到十二月底，

647
00:05:13,440 --> 00:05:15,403
所有的雌性都已经被骑上去。

648
00:05:19,500 --> 00:05:24,060
只有最强壮的雄性，长着最大角的雄性，

649
00:05:24,060 --> 00:05:26,500
那些皮毛最黑的，

650
00:05:26,500 --> 00:05:30,053
最强的，被雌性接受。

651
00:05:38,400 --> 00:05:41,850
伊比利亚野山羊的自然选择过程

652
00:05:41,850 --> 00:05:44,150
其中包括最具震撼性

653
00:05:44,150 --> 00:05:47,176
以及动物王国中的危险的战斗。

654
00:05:47,176 --> 00:05:49,843
（不祥的音乐）

655
00:05:56,399 --> 00:06:01,399
（喇叭声响起）（戏剧性音乐）

656
00:06:39,370 --> 00:06:42,543
其中一些战斗可能会持续近一个小时。

657
00:06:48,320 --> 00:06:51,780
最令人好奇的是，那些战斗者

658
00:06:51,780 --> 00:06:55,023
实际上是大头狼的副手。

659
00:06:57,690 --> 00:07:01,180
这样，伊比利亚野山羊就避免了战斗

660
00:07:01,180 --> 00:07:04,020
许多年轻雄性，一只接一只，

661
00:07:04,020 --> 00:07:06,300
这可能会让雄性精疲力竭

662
00:07:06,300 --> 00:07:08,513
并威胁到它的生育权。

663
00:07:17,157 --> 00:07:22,157
（蹄刮擦声）（风呼啸声）

664
00:07:37,700 --> 00:07:38,990
但无论如何，

665
00:07:38,990 --> 00:07:43,583
说“是”或“否”的总是雌性。

666
00:08:00,690 --> 00:08:02,560
伊比利半岛覆盖

667
00:08:02,560 --> 00:08:05,683
近六十万平方公里。

668
00:08:07,207 --> 00:08:10,510
撒哈拉沙漠可容纳十五个伊比利半岛

669
00:08:11,350 --> 00:08:13,913
亚马逊河流域有十处。

670
00:08:17,040 --> 00:08:21,210
它仅占欧洲面积的百分之五，

671
00:08:21,210 --> 00:08:23,430
但其野生动物的价値

672
00:08:23,430 --> 00:08:25,023
与其大小不成比例。

673
00:08:28,570 --> 00:08:31,320
这些土地极为重要

674
00:08:31,320 --> 00:08:32,860
因为它们的多样性

675
00:08:32,860 --> 00:08:35,023
及其地缘战略位置。

676
00:08:37,280 --> 00:08:40,170
在南部，靠近非洲的地方，

677
00:08:40,170 --> 00:08:42,220
来自大西洋的阿尔加维，

678
00:08:42,220 --> 00:08:44,560
到地中海的海滩，

679
00:08:44,560 --> 00:08:46,323
它从不结冰。

680
00:08:49,410 --> 00:08:53,853
到非洲直线距离仅需一小时，甚至更短。

681
00:08:57,430 --> 00:09:01,120
许多旅行者从一个世界到另一个世界旅行，

682
00:09:01,120 --> 00:09:03,033
尤其是春季和秋季。

683
00:09:07,630 --> 00:09:10,243
然而，这些大雁是在冬天抵达的，

684
00:09:11,720 --> 00:09:14,210
但那是因为它们不是来自南方，

685
00:09:14,210 --> 00:09:16,623
而是来自北极圈以外。

686
00:09:19,160 --> 00:09:21,960
它们在斯堪纳维亚的食物现在已经冷冻了。

687
00:09:21,960 --> 00:09:24,290
它们来这里是为了寻找莎草，

688
00:09:24,290 --> 00:09:27,293
生长在浅水中的水生植物。

689
00:09:28,500 --> 00:09:31,410
虎耳草的根非常坚韧

690
00:09:31,410 --> 00:09:32,940
你的砂囊里有一点沙

691
00:09:32,940 --> 00:09:35,073
非常有利于消化它。

692
00:09:38,890 --> 00:09:40,660
多纳纳沙丘的沙

693
00:09:40,660 --> 00:09:42,363
会帮助大雁完成这项工作。

694
00:09:43,365 --> 00:09:46,032
（大雁鸣叫）

695
00:09:48,950 --> 00:09:52,090
冬天，大雁们聚集成大群

696
00:09:52,090 --> 00:09:54,203
多达数万只鸟。

697
00:09:55,690 --> 00:09:59,130
只有非常特殊且丰富的生态系统

698
00:09:59,130 --> 00:10:02,030
可以维持它们，例如湿地

699
00:10:02,030 --> 00:10:03,500
瓜达尔基维尔河，

700
00:10:03,500 --> 00:10:06,110
里斯本南部的塔霍河口，

701
00:10:06,110 --> 00:10:08,993
或萨莫拉省的维拉法菲拉湖。

702
00:10:09,965 --> 00:10:14,965
（欢快的音乐）（大雁鸣声）

703
00:10:37,010 --> 00:10:38,820
西班牙的这个寒冷地区

704
00:10:38,820 --> 00:10:41,050
必须提醒它们北方的家乡

705
00:10:41,050 --> 00:10:43,160
因为它们受到低温

706
00:10:43,160 --> 00:10:44,313
就像一位老朋友一样。

707
00:10:49,050 --> 00:10:51,960
夜幕降临，大雁们在水中避难

708
00:10:51,960 --> 00:10:55,823
安全地睡觉，免受狼、狐狸和野猪的伤害。

709
00:10:57,087 --> 00:10:59,754
（大雁鸣叫）

710
00:11:04,050 --> 00:11:06,880
但在夜间和黎明时分，

711
00:11:06,880 --> 00:11:09,080
从十二月到二月，

712
00:11:09,080 --> 00:11:11,333
这些浅水区结冰了。

713
00:11:12,751 --> 00:11:15,751
（调皮的音乐）

714
00:11:22,020 --> 00:11:25,020
也就是说，除非成千上万只大雁

715
00:11:25,020 --> 00:11:27,770
用脚不停地划动，

716
00:11:27,770 --> 00:11:30,510
防止冰形成并困住它们。

717
00:11:31,450 --> 00:11:33,630
这就是为什么沿岸地区的水

718
00:11:33,630 --> 00:11:35,240
大雁睡觉的地方

719
00:11:35,240 --> 00:11:37,540
没有被坚硬的冰层覆盖

720
00:11:37,540 --> 00:11:38,840
就像湖的其余部份一样。

721
00:11:44,500 --> 00:11:47,430
水温低于冰点，

722
00:11:47,430 --> 00:11:50,723
但透过移动它们的腿，羊群保持了液体的状态。

723
00:11:52,490 --> 00:11:55,770
它们的羽毛涂上油并梳理整齐，

724
00:11:55,770 --> 00:11:57,510
是完美的绝缘材料

725
00:11:57,510 --> 00:11:59,810
防止皮肤接触

726
00:11:59,810 --> 00:12:01,573
与水或空气。

727
00:12:05,960 --> 00:12:08,640
它们的腿最大限度地减少了血液流动

728
00:12:08,640 --> 00:12:10,723
所以身体热量的损失很小。

729
00:12:13,700 --> 00:12:16,200
该物种完全适应

730
00:12:16,200 --> 00:12:18,392
冬季的低温。

731
00:12:18,392 --> 00:12:23,392
（调皮的音乐）（大雁鸣声）

732
00:12:27,172 --> 00:12:29,922
（风呼啸）

733
00:12:38,300 --> 00:12:41,310
比利牛斯山的冬天总是白色的

734
00:12:42,210 --> 00:12:43,783
并且极度寒冷。

735
00:12:45,520 --> 00:12:47,950
但乌鸦的血正在沸腾

736
00:12:47,950 --> 00:12:50,060
在一月深处，

737
00:12:50,060 --> 00:12:53,723
海拔三千多公尺。

738
00:12:57,810 --> 00:13:00,560
乌鸦选择飞越风力最强

739
00:13:00,560 --> 00:13:03,080
也是今天最艰难的山峰，

740
00:13:03,080 --> 00:13:05,170
因为是时候展示剩下的了

741
00:13:05,170 --> 00:13:07,880
它们每一个都是由什么组成的。

742
00:13:07,880 --> 00:13:10,547
（乌鸦叫声）

743
00:13:11,930 --> 00:13:14,640
乌鸦群在冬天聚在一起

744
00:13:14,640 --> 00:13:16,733
表演杂技。

745
00:13:17,600 --> 00:13:19,910
这些并非是练习而已。

746
00:13:19,910 --> 00:13:22,613
它们的俯冲轰炸和翻筋斗动作十分危险。

747
00:13:25,370 --> 00:13:28,970
彼此飞得如此近，速度如此之快，

748
00:13:28,970 --> 00:13:32,980
伴随强烈侧风和低能见度，

749
00:13:32,980 --> 00:13:35,713
增加了它们失去控制的可能性。

750
00:13:38,680 --> 00:13:41,210
只是轻微扭伤，

751
00:13:41,210 --> 00:13:44,829
扭曲的翅膀，在这里必定意味着死亡。

752
00:13:44,829 --> 00:13:47,579
（激昂的音乐）

753
00:14:18,010 --> 00:14:21,470
毫无疑问，这些鸟的智力

754
00:14:21,470 --> 00:14:23,373
让它们享受这个游戏。

755
00:14:24,330 --> 00:14:27,123
而且它们对任何物体都确实如此。

756
00:14:28,930 --> 00:14:31,960
它们很开心地互相夺走它，

757
00:14:31,960 --> 00:14:34,743
但其最终目的并不是为了好玩。

758
00:14:36,940 --> 00:14:40,500
情侣们正在同步它们的生理时钟

759
00:14:40,500 --> 00:14:42,973
并加强它们的情感纽带。

760
00:14:47,370 --> 00:14:50,650
它们几乎都会找到伴侣，

761
00:14:50,650 --> 00:14:52,940
尽管它们并不是在寻找最好的鸟，

762
00:14:52,940 --> 00:14:56,000
或最坚强或最勇敢的鸟，

763
00:14:56,000 --> 00:14:58,063
而是寻找最佳匹配，

764
00:14:58,950 --> 00:15:01,223
与之同步的鸟。

765
00:15:08,975 --> 00:15:11,558
（轻柔音乐）

766
00:15:15,280 --> 00:15:17,930
在伊比利半岛的许多地方，

767
00:15:17,930 --> 00:15:21,080
冬季的寒冷和降雪使工作变得更加困难

768
00:15:21,080 --> 00:15:22,443
每天获取食物。

769
00:15:26,930 --> 00:15:30,253
这是一年中发生第一批死亡事件的时期，

770
00:15:33,530 --> 00:15:35,330
丢弃多余的动物

771
00:15:35,330 --> 00:15:37,080
它们去年春天诞生。

772
00:16:00,832 --> 00:16:03,582
（激昂的音乐）

773
00:16:17,728 --> 00:16:18,883
（激昂的音乐结束）

774
00:16:18,883 --> 00:16:21,633
（鸟鸣声）

775
00:16:30,930 --> 00:16:32,540
随着寒冷的临近，

776
00:16:32,540 --> 00:16:35,703
八哥的社会行为发生了根本性的改变。

777
00:16:38,660 --> 00:16:40,680
春天它们养育雏鸟

778
00:16:40,680 --> 00:16:42,253
同时以孤立的对儿形式生活。

779
00:16:43,610 --> 00:16:46,340
然后在秋天，它们逐渐加入

780
00:16:46,340 --> 00:16:48,783
它们的邻居分成小组来觅食。

781
00:16:54,000 --> 00:16:56,800
现在是冬天，它们聚集在一起

782
00:16:56,800 --> 00:16:58,773
成群结队地睡觉，

783
00:16:59,620 --> 00:17:02,923
有时，数量达数百万只。

784
00:17:07,850 --> 00:17:10,020
这个想法是针对年轻的椋鸟

785
00:17:10,020 --> 00:17:13,723
占据羊群外围的区域，

786
00:17:15,020 --> 00:17:17,180
哪个才是最危险的区域

787
00:17:17,180 --> 00:17:19,483
因为那是掠食者发动攻击的地方。

788
00:17:23,550 --> 00:17:26,470
最有经验的椋鸟几乎总是

789
00:17:26,470 --> 00:17:28,023
飞在鸟群的中心，

790
00:17:29,660 --> 00:17:32,620
它们受到不可逾越的盾牌的保护

791
00:17:32,620 --> 00:17:35,543
由许多缺乏经验的新秀组成。

792
00:17:38,400 --> 00:17:41,050
为了换取冒着生命危险，

793
00:17:41,050 --> 00:17:44,360
这些年轻的八哥学习如何更好地飞翔。

794
00:17:44,360 --> 00:17:47,270
最重要的是，它们必须去哪里寻找食物

795
00:17:47,270 --> 00:17:49,073
以及夜幕降临时的庇护所。

796
00:18:01,420 --> 00:18:04,290
过去三天里，每天黄昏时分，

797
00:18:04,290 --> 00:18:06,320
它们遭到两只雀鹰的攻击

798
00:18:06,320 --> 00:18:08,670
当它们在树枝上栖息时。

799
00:18:10,850 --> 00:18:13,533
空中还有一只游隼。

800
00:18:15,260 --> 00:18:18,203
这是唯一能在空中打败它们的鸟。

801
00:18:19,445 --> 00:18:22,445
（忧郁的音乐）

802
00:18:25,080 --> 00:18:28,020
但每天有三只鸟伤亡

803
00:18:28,020 --> 00:18:31,720
三百万的损失并不算太大。

804
00:18:31,720 --> 00:18:34,890
此外，从统计学上来说，它们肯定

805
00:18:34,890 --> 00:18:37,760
那些不知道如何同步行动的鸟

806
00:18:37,760 --> 00:18:40,980
和其它成员在同一瞬间

807
00:18:40,980 --> 00:18:41,880
它们的中队。

808
00:18:44,130 --> 00:18:45,950
但多亏了那次扑杀，

809
00:18:45,950 --> 00:18:49,387
每年，椋鸟群都会飞得更好。

810
00:18:50,644 --> 00:18:53,394
（雄伟的音乐）

811
00:20:19,364 --> 00:20:22,114
（风呼啸）

812
00:20:32,380 --> 00:20:35,340
到一月中旬，进入冬眠期

813
00:20:35,340 --> 00:20:37,423
已经进入最艰难的阶段。

814
00:20:39,170 --> 00:20:42,470
地下，埋在树干里，

815
00:20:42,470 --> 00:20:45,330
或浸入冰冷的水中，

816
00:20:45,330 --> 00:20:47,910
许多生物在等待，

817
00:20:47,910 --> 00:20:50,193
它们的生活暂时陷入停滞。

818
00:20:52,290 --> 00:20:55,943
它们中的许多生物将永远无法醒来。

819
00:21:01,740 --> 00:21:03,983
冬眠并不容易。

820
00:21:11,150 --> 00:21:14,290
伊比利半岛最常见的青蛙，

821
00:21:14,290 --> 00:21:17,560
佩雷斯蛙是准备最充份的两栖动物之一

822
00:21:17,560 --> 00:21:22,560
抵御低温，甚至冰冻。

823
00:21:26,160 --> 00:21:29,410
如果冰晶在生物体内形成，

824
00:21:29,410 --> 00:21:31,170
造成无法挽回的损失

825
00:21:31,170 --> 00:21:33,763
这几乎总是会导致死亡。

826
00:21:35,060 --> 00:21:38,990
细胞中溶解的水结冰时会膨胀

827
00:21:38,990 --> 00:21:41,683
并破坏细胞膜和细胞壁。

828
00:21:43,950 --> 00:21:46,730
必须在极端温度下生存的动物

829
00:21:46,730 --> 00:21:48,890
冬眠时有物质

830
00:21:48,890 --> 00:21:51,230
保护它们免受冻害，

831
00:21:51,230 --> 00:21:54,240
并限制每个细胞体积的增加。

832
00:21:54,240 --> 00:21:55,653
即使它冻结了。

833
00:21:58,100 --> 00:22:01,810
这是无脊椎动物和人类必须适应的

834
00:22:01,810 --> 00:22:03,850
而脊椎动物已经发展

835
00:22:03,850 --> 00:22:06,813
这样它们就可以冬眠而不会死亡。

836
00:22:09,585 --> 00:22:12,168
（风势）

837
00:22:18,510 --> 00:22:21,760
冬眠是一个极佳的策略。

838
00:22:21,760 --> 00:22:23,440
自我隔离的过程

839
00:22:23,440 --> 00:22:25,380
远离恶劣的大陆性气候

840
00:22:25,380 --> 00:22:28,070
或高山上的恶劣天气，

841
00:22:28,070 --> 00:22:30,770
导致许多动物无法获取食物

842
00:22:30,770 --> 00:22:32,473
甚至消化它。

843
00:22:35,370 --> 00:22:38,140
它之所以有效，是因为寒冷能使动物

844
00:22:38,140 --> 00:22:41,070
睡觉时体温很低。

845
00:22:41,070 --> 00:22:45,343
因此它将能耗降至几乎为零。

846
00:22:52,358 --> 00:22:55,108
（鸟鸣声）

847
00:22:59,212 --> 00:23:01,860
如果几天内太阳稍微暖和一点，

848
00:23:01,860 --> 00:23:04,710
它可以让一些冬眠的动物醒来

849
00:23:04,710 --> 00:23:06,670
稍微走动一下，

850
00:23:06,670 --> 00:23:09,687
甚至出去散步或喝水。

851
00:23:11,090 --> 00:23:13,120
但这种热量还不够

852
00:23:13,120 --> 00:23:15,203
进行新陈代谢过程。

853
00:23:16,570 --> 00:23:18,903
所以它们必须再回去睡觉。

854
00:23:36,700 --> 00:23:39,520
鸟儿不知道如何冬眠，

855
00:23:39,520 --> 00:23:42,520
此外，在半岛的西南部，

856
00:23:42,520 --> 00:23:44,990
西班牙和葡萄牙边境附近，

857
00:23:44,990 --> 00:23:47,393
天气变冷，但不是很冷。

858
00:23:53,750 --> 00:23:56,690
鹰开始成对飞行

859
00:23:58,440 --> 00:24:01,963
而雄性和雌性会互相追逐几个小时。

860
00:24:15,980 --> 00:24:19,370
当它们休息时，它们会尝试不同的石头

861
00:24:19,370 --> 00:24:20,960
选择它们最喜欢的一个

862
00:24:20,960 --> 00:24:23,193
为它们未来的巢穴提供平台。

863
00:24:39,220 --> 00:24:42,650
吉塔诺瀑布，最具代表性的地方之一

864
00:24:42,650 --> 00:24:45,300
在西班牙的蒙弗拉格国家公园，

865
00:24:45,300 --> 00:24:47,350
是最大的殖民地之一

866
00:24:47,350 --> 00:24:49,313
世界上该物种的数量。

867
00:25:07,030 --> 00:25:09,890
鹰的数量正在减少

868
00:25:09,890 --> 00:25:12,350
直到几十年前，

869
00:25:12,350 --> 00:25:14,560
但现在它们正在反弹

870
00:25:14,560 --> 00:25:17,393
并使乡村恢复平衡。

871
00:25:34,940 --> 00:25:38,450
伊比利半岛南部海岸无人冬眠。

872
00:25:38,450 --> 00:25:41,060
在这里，在一年中最糟糕的时期，

873
00:25:41,060 --> 00:25:43,000
天空有点阴

874
00:25:43,000 --> 00:25:44,610
最多气温会下降

875
00:25:44,610 --> 00:25:47,140
降低五到十度，

876
00:25:47,140 --> 00:25:49,453
但天气并没有眞正变冷。

877
00:25:51,870 --> 00:25:55,710
尽管昆虫和节肢动物的数量减少了，

878
00:25:55,710 --> 00:25:58,123
就像火烈鸟赖以生存的卤虫一样。

879
00:25:59,720 --> 00:26:01,813
这迫使它们扩散开来。

880
00:26:05,440 --> 00:26:08,350
为了找到食物，它们必须搅动泥土

881
00:26:08,350 --> 00:26:11,100
用脚，跺脚

882
00:26:11,100 --> 00:26:12,750
就像在跳佛朗明哥舞一样。

883
00:26:13,915 --> 00:26:18,915
（欢快的佛朗明哥音乐）

884
00:27:11,370 --> 00:27:13,500
温和的西南风

885
00:27:13,500 --> 00:27:15,763
帮助火烈鸟再次飞回家，

886
00:27:16,740 --> 00:27:19,120
还扫了很多非洲沙

887
00:27:19,120 --> 00:27:20,513
到多纳纳湿地，

888
00:27:22,130 --> 00:27:26,283
创造出极为罕见的沙丘生态系。

889
00:27:31,800 --> 00:27:33,500
已经适应的植物物种

890
00:27:33,500 --> 00:27:35,210
对于这种类型的基质，

891
00:27:35,210 --> 00:27:38,780
几乎没有水份，也缺乏营养，

892
00:27:38,780 --> 00:27:41,380
建立茎和根的屏障

893
00:27:41,380 --> 00:27:43,363
使沙稍微固定在原处。

894
00:27:44,310 --> 00:27:46,873
这就是逐渐形成沙丘的过程。

895
00:27:48,400 --> 00:27:51,913
但沙就像液体一样，无法静止不动。

896
00:27:53,290 --> 00:27:54,653
沙丘移动。

897
00:27:56,900 --> 00:28:00,400
没有什么可以阻止它们彻底前进，

898
00:28:00,400 --> 00:28:03,983
每年移动的速度为三至六公尺。

899
00:28:08,470 --> 00:28:10,690
那是一个非常缓慢的动作，

900
00:28:10,690 --> 00:28:13,140
但最终它们会到达沼泽

901
00:28:13,140 --> 00:28:15,963
并会沉入其中而消失。

902
00:28:18,190 --> 00:28:20,500
在多雨的年份，水的力量

903
00:28:20,500 --> 00:28:24,620
把沙扫走并带回大海，

904
00:28:24,620 --> 00:28:25,933
关闭循环。

905
00:28:26,810 --> 00:28:28,060
但在旅途中，

906
00:28:28,060 --> 00:28:30,723
沙丘毁灭了其路径上的一切。

907
00:28:32,570 --> 00:28:35,740
它们像海面上的波浪一样排列。

908
00:28:35,740 --> 00:28:38,573
这里有六条主要的沙丘线。

909
00:28:40,750 --> 00:28:43,440
植物在空间中找到了栖身之所

910
00:28:43,440 --> 00:28:45,870
在每一排沙丘之间，

911
00:28:45,870 --> 00:28:48,243
但只能持续一段有限的时间，

912
00:28:52,230 --> 00:28:56,253
石松形成壮丽茂密的森林，

913
00:28:57,320 --> 00:29:00,690
但移动的沙丘最终会包围它们

914
00:29:00,690 --> 00:29:03,192
并逐渐将它们全部埋葬。

915
00:29:03,192 --> 00:29:06,192
（悬疑音乐）

916
00:29:10,970 --> 00:29:12,343
或者几乎全部。

917
00:29:14,080 --> 00:29:18,430
偶尔，一棵松树会在适当的地方发芽

918
00:29:18,430 --> 00:29:21,900
或比其它的长得更快、更高一些。

919
00:29:21,900 --> 00:29:23,710
而且它不会被窒息而死

920
00:29:23,710 --> 00:29:26,923
因为沙不能完全覆盖它。

921
00:29:28,060 --> 00:29:29,930
这是例外，

922
00:29:29,930 --> 00:29:32,270
沙丘经过的见证者，

923
00:29:32,270 --> 00:29:35,683
或许也预示着新种石松的未来。

924
00:29:37,883 --> 00:29:40,466
（风势）

925
00:29:47,750 --> 00:29:50,330
湿地和沼泽是生态系统

926
00:29:50,330 --> 00:29:52,563
生物多样性集中的地方。

927
00:29:54,440 --> 00:29:57,673
对于水鸟来说这一点尤其明显。

928
00:29:59,540 --> 00:30:01,870
这里有很多水鸟

929
00:30:01,870 --> 00:30:05,260
以及种类繁多的水鸟。

930
00:30:05,260 --> 00:30:08,930
如果有鸟类，那么就有鱼类和无脊椎动物

931
00:30:08,930 --> 00:30:11,433
以及植被和捕食者。

932
00:30:12,670 --> 00:30:15,943
这些宝贵的湿润栖息地的作用至关重要。

933
00:30:18,880 --> 00:30:22,660
桑托纳沼泽、塔霍河口，

934
00:30:22,660 --> 00:30:25,983
埃布罗河三角洲、多纳纳或代米耶尔湿地。

935
00:30:26,860 --> 00:30:29,220
这些也许是最重要的，

936
00:30:29,220 --> 00:30:31,660
对于本地物种来说，

937
00:30:31,660 --> 00:30:33,830
以及利用它们的迁移物种

938
00:30:33,830 --> 00:30:37,123
作为旅途中休息进食的地方。

939
00:30:41,610 --> 00:30:44,780
某些鸭甚至会在这里度过整个季节

940
00:30:44,780 --> 00:30:46,690
当它们的原籍国的气候

941
00:30:46,690 --> 00:30:47,893
是不适宜居住的。

942
00:30:52,320 --> 00:30:55,453
如今，在伊比利亚半岛过冬的鸟类数量众多。

943
00:30:59,660 --> 00:31:01,400
尽管每年这个时候

944
00:31:01,400 --> 00:31:03,133
它们可能不是每天都可见。

945
00:31:04,140 --> 00:31:07,010
恶劣的天气常常迫使它们寻找庇护所

946
00:31:07,010 --> 00:31:09,280
在芦苇和香蒲中。

947
00:31:09,280 --> 00:31:11,423
景观看起来空旷。

948
00:31:31,354 --> 00:31:33,937
（风势）

949
00:31:43,930 --> 00:31:46,440
狼的出现又变得正常了

950
00:31:46,440 --> 00:31:49,259
位于伊比利半岛的西北方。

951
00:31:49,259 --> 00:31:52,092
（狼咆哮）

952
00:31:54,230 --> 00:31:56,730
也许它们最丰富的地方

953
00:31:56,730 --> 00:32:01,260
从Montesinho自然公园到Peneda-Geres，

954
00:32:01,260 --> 00:32:03,623
葡萄牙唯一的国家公园。

955
00:32:08,124 --> 00:32:10,874
（狼嚎）

956
00:32:18,990 --> 00:32:21,890
每天都有这么多动物跨越边境

957
00:32:21,890 --> 00:32:23,760
西班牙和葡萄牙之间，

958
00:32:23,760 --> 00:32:26,220
前往库莱布拉山脉，

959
00:32:26,220 --> 00:32:29,230
甚至到达加利西亚的安卡雷斯山脉，

960
00:32:29,230 --> 00:32:31,320
交叉并强化基因

961
00:32:31,320 --> 00:32:32,673
和它们的血统。

962
00:32:37,820 --> 00:32:40,753
这些土地的保护被证明是成功的，

963
00:32:41,950 --> 00:32:45,440
以及一个顶级掠食者可以繁殖的生态系统

964
00:32:45,440 --> 00:32:47,193
是一个健康的生态系。

965
00:32:57,120 --> 00:33:00,440
同样，伊比利亚狼也在殖民

966
00:33:00,440 --> 00:33:03,343
重新成为杜罗河以南的旧领土。

967
00:33:05,170 --> 00:33:07,380
甚至已经到了中部的山区

968
00:33:07,380 --> 00:33:09,473
位于马德里附近的半岛。

969
00:33:12,450 --> 00:33:15,320
寒冷的冬夜再次见证

970
00:33:15,320 --> 00:33:17,380
听到新包的声音

971
00:33:17,380 --> 00:33:20,174
夺回它们曾经游荡的土地

972
00:33:20,174 --> 00:33:22,498
并组织起来进行狩猎。

973
00:33:22,498 --> 00:33:25,248
（狼嚎）

974
00:33:47,030 --> 00:33:49,410
虽然已经快到三月了，

975
00:33:49,410 --> 00:33:51,810
昨晚是今年最冷的夜晚

976
00:33:51,810 --> 00:33:53,700
在瓦尔塞恩的森林里

977
00:33:53,700 --> 00:33:55,550
在中央山脉，

978
00:33:55,550 --> 00:33:58,303
海拔近两千公尺。

979
00:34:00,480 --> 00:34:02,683
尖锐的松针很坚韧，

980
00:34:04,340 --> 00:34:06,083
就像仙人掌的刺一样，

981
00:34:07,880 --> 00:34:09,830
这些树叶

982
00:34:09,830 --> 00:34:13,663
既能忍受酷热，又能忍受严寒。

983
00:34:14,590 --> 00:34:18,500
事实上，在这片极端的土地上，几乎所有的事情

984
00:34:18,500 --> 00:34:20,230
做好了适应温度的准备

985
00:34:20,230 --> 00:34:23,550
现在气温已降至零下廿度

986
00:34:23,550 --> 00:34:25,763
夏天可达卅度以上。

987
00:34:30,180 --> 00:34:34,423
大气温度范围为五十度。

988
00:34:45,090 --> 00:34:48,780
直线距离往南一百五十公里，

989
00:34:48,780 --> 00:34:53,770
在卡瓦内罗斯，土地也遭受了严重霜冻。

990
00:34:53,770 --> 00:34:56,893
寒冷夺走了这里许多动物的生命。

991
00:34:59,450 --> 00:35:01,633
这只马鹿无法承受。

992
00:35:03,020 --> 00:35:05,170
但它也有利于自然选择

993
00:35:05,170 --> 00:35:07,233
最适应的个体。

994
00:35:08,290 --> 00:35:11,520
这只狐狸正在充分利用

995
00:35:11,520 --> 00:35:13,630
运气给予它的机会。

996
00:35:13,630 --> 00:35:16,950
狐狸是猎者，但和几乎所有的掠食者一样，

997
00:35:16,950 --> 00:35:19,503
它们不会对好腐肉嗤之以鼻。

998
00:35:25,860 --> 00:35:28,640
但鹰已经发现了

999
00:35:28,640 --> 00:35:31,310
并且没有心情分享。

1000
00:35:31,310 --> 00:35:34,463
这里没生物敢跟这么多鹰对抗。

1001
00:35:39,456 --> 00:35:41,860
伊比利半岛鹰

1002
00:35:41,860 --> 00:35:45,203
无论在寒冷或炎热的天气里都能轻松找到食物。

1003
00:35:46,820 --> 00:35:49,463
总有生物为它们而死。

1004
00:35:52,800 --> 00:35:55,330
这个物种在这里濒临灭绝

1005
00:35:55,330 --> 00:35:57,440
就在几十年前，

1006
00:35:57,440 --> 00:36:00,383
但现在数量已经回升。

1007
00:36:03,430 --> 00:36:06,300
鹰现在开始选择配偶

1008
00:36:06,300 --> 00:36:07,963
并准备抚养后代。

1009
00:36:08,860 --> 00:36:11,670
雌性即将生蛋。

1010
00:36:11,670 --> 00:36:14,190
它们的需求和饥饿感更大

1011
00:36:14,190 --> 00:36:16,850
比一年中的任何其它时间都要多，

1012
00:36:16,850 --> 00:36:19,553
这就是为什么它们更加凶猛。

1013
00:36:19,553 --> 00:36:22,720
（鹰争吵）

1014
00:36:37,960 --> 00:36:40,050
欧亚雕鴞抚养幼鸟

1015
00:36:40,050 --> 00:36:42,460
在最寒冷的天气。

1016
00:36:42,460 --> 00:36:44,790
甚至比鹰还早。

1017
00:36:44,790 --> 00:36:47,470
这些幼鸟几周前出生，

1018
00:36:47,470 --> 00:36:50,843
但有些甚至在一月就破壳而出了。

1019
00:36:54,140 --> 00:36:58,500
啮齿动物、野兔、甚至狐狸，
偶尔还有其它飞禽走兽，

1020
00:36:58,500 --> 00:37:00,830
是巢穴中始终存在的猎物

1021
00:37:00,830 --> 00:37:04,003
世界上最大的夜间猛禽之一。

1022
00:37:07,100 --> 00:37:09,970
猫头鹰和所有顶级掠食者一样，

1023
00:37:09,970 --> 00:37:12,380
帮助保存猎物的基因库

1024
00:37:12,380 --> 00:37:13,853
健康而平衡。

1025
00:37:18,230 --> 00:37:22,040
它们在夜间狩猎，充份利用机会

1026
00:37:22,040 --> 00:37:24,363
它们用敏锐的眼睛察觉到，

1027
00:37:26,660 --> 00:37:28,803
当其它生物都看不到某样东西时。

1028
00:37:38,644 --> 00:37:41,561
（翅膀扇动）

1029
00:37:49,087 --> 00:37:52,004
（野兔吱吱叫）

1030
00:38:16,180 --> 00:38:18,840
今天伊比利半岛迎来黎明

1031
00:38:18,840 --> 00:38:20,653
比昨天早一点。

1032
00:38:22,960 --> 00:38:26,500
在阿拉贡南部，数以万计的鹤，

1033
00:38:26,500 --> 00:38:30,020
像大雁一样，晚上躱在水里，

1034
00:38:30,020 --> 00:38:32,720
它们相信在那里不会受到食肉动物的攻击。

1035
00:38:41,610 --> 00:38:44,433
寒冷仍不肯离去，

1036
00:38:45,340 --> 00:38:48,853
尽管现在已经比较羸弱，而且时间也不多了。

1037
00:38:50,350 --> 00:38:53,600
三月春分即将来临，

1038
00:38:53,600 --> 00:38:56,470
鹤群正等待开始回家

1039
00:38:56,470 --> 00:38:58,308
的旅程讯息。

1040
00:38:58,308 --> 00:39:01,480
（鹤鸣）

1041
00:39:01,480 --> 00:39:03,273
但迹像还没出现。

1042
00:39:11,390 --> 00:39:13,640
今天早晨雾很浓

1043
00:39:16,100 --> 00:39:19,653
水滴附着在所有东西上，

1044
00:39:21,010 --> 00:39:24,698
但阳光却越来越温煦。

1045
00:39:24,698 --> 00:39:27,281
（轻柔音乐）

1046
00:39:43,260 --> 00:39:47,863
夜晚越来越短，寒冷也不再那么强烈。

1047
00:39:50,160 --> 00:39:54,050
今天水没有像以前那样结冰

1048
00:39:54,050 --> 00:39:56,240
在内陆的许多河流和湖泊中

1049
00:39:56,240 --> 00:39:57,913
伊比利半岛。

1050
00:40:00,930 --> 00:40:04,160
冬季产生辐射雾

1051
00:40:04,160 --> 00:40:07,220
透过夜间土壤和水流失的热量

1052
00:40:09,040 --> 00:40:12,350
并以微小水颗粒的形式上升

1053
00:40:12,350 --> 00:40:14,523
悬浮在空中。

1054
00:40:18,360 --> 00:40:21,740
在黑夜与白昼之间的黄昏中，

1055
00:40:21,740 --> 00:40:24,880
微弱的光线笼罩着水蒸气

1056
00:40:24,880 --> 00:40:26,890
在明亮的阳光使之成为可能之前

1057
00:40:26,890 --> 00:40:30,563
看清每件事、每个人。

1058
00:40:33,870 --> 00:40:37,120
这是许多猎者喜欢的时间

1059
00:40:37,120 --> 00:40:39,420
因为它们有更大的成功机会。

1060
00:40:42,330 --> 00:40:45,303
现在看到水獭的机会更大。

1061
00:40:52,490 --> 00:40:55,790
西班牙和葡萄牙所做的保育工作

1062
00:40:55,790 --> 00:40:58,120
旨在清理和改善状况

1063
00:40:58,120 --> 00:41:00,490
河流和湖泊允许

1064
00:41:00,490 --> 00:41:03,273
这标志性物种再次繁衍生息。

1065
00:41:05,040 --> 00:41:08,210
从加利西亚到安达卢西亚，

1066
00:41:08,210 --> 00:41:10,433
从阿连特茹到比利牛斯山，

1067
00:41:11,520 --> 00:41:14,473
任何有小龙虾、鱼和两栖动物的地方。

1068
00:41:26,938 --> 00:41:29,688
（蟾蜍嘎嘎叫）

1069
00:41:39,320 --> 00:41:42,330
许多两栖类发现二月的天气状况

1070
00:41:42,330 --> 00:41:44,883
三月初有利于繁殖。

1071
00:41:49,390 --> 00:41:52,510
但在这些地方，即使在冬天，

1072
00:41:52,510 --> 00:41:55,500
温煦的日子经常出现

1073
00:41:55,500 --> 00:41:57,790
这使得黄条背蟾蜍

1074
00:41:57,790 --> 00:42:00,343
和族群开始唱歌。

1075
00:42:06,670 --> 00:42:10,000
水温对它们的语调至关重要

1076
00:42:10,000 --> 00:42:12,073
因为它会影响它们的声带。

1077
00:42:14,500 --> 00:42:16,380
雄性发出的声音

1078
00:42:16,380 --> 00:42:18,633
根据音色来吸引雌性。

1079
00:42:20,240 --> 00:42:22,910
对它们来说，最理想的是水

1080
00:42:22,910 --> 00:42:25,643
约为摄氏九度。

1081
00:42:29,670 --> 00:42:31,610
两栖类狂欢

1082
00:42:31,610 --> 00:42:34,050
在很短的时间内，

1083
00:42:34,050 --> 00:42:35,610
根据天气情况，

1084
00:42:35,610 --> 00:42:38,423
每片水域都有自己的特别日子。

1085
00:42:39,490 --> 00:42:43,440
在大多数蟾蜍族群中，百分之九十的交配发生在

1086
00:42:43,440 --> 00:42:47,263
在同一天或两天内的几个小时内。

1087
00:42:52,530 --> 00:42:56,343
有些蟾蜍的交配时间可持续长达廿小时。

1088
00:42:57,890 --> 00:43:01,430
虽然最困难的部份不会持续那么长时间，

1089
00:43:01,430 --> 00:43:04,830
而是不能继续拥抱彼此

1090
00:43:04,830 --> 00:43:06,950
在被所有雄性骚扰的同时

1091
00:43:06,950 --> 00:43:09,713
傍晚时分还没找到伴侣。

1092
00:43:12,530 --> 00:43:14,803
雄性比雌性多，

1093
00:43:16,070 --> 00:43:18,623
有时甚至高达廿倍以上。

1094
00:43:25,340 --> 00:43:28,073
它们中的许多将永远无法繁衍后代。

1095
00:43:33,740 --> 00:43:36,530
这只拼命想分手

1096
00:43:36,530 --> 00:43:38,633
交配伴侣的性爱互动。

1097
00:43:40,920 --> 00:43:44,250
但要解除它们的交配几乎是不可能

1098
00:43:44,250 --> 00:43:47,010
一旦受精过程开始。

1099
00:43:47,010 --> 00:43:49,923
（蟾蜍咕噜声）

1100
00:43:49,923 --> 00:43:52,673
（水晃动）

1101
00:44:01,990 --> 00:44:04,130
它必须打断雄性的手臂

1102
00:44:04,130 --> 00:44:06,783
合法赢得生育权。

1103
00:44:07,822 --> 00:44:10,572
（蟾蜍嘎嘎叫）

1104
00:44:25,940 --> 00:44:28,660
两栖类通常不会等到春天

1105
00:44:28,660 --> 00:44:31,363
来完成增加其数量的任务。

1106
00:44:32,630 --> 00:44:35,130
尤其是它们的蝌蚪，

1107
00:44:35,130 --> 00:44:37,140
取决于水不蒸发

1108
00:44:37,140 --> 00:44:40,030
或过早渗入地下，

1109
00:44:40,030 --> 00:44:43,520
有时春天来临又干燥又炎热，

1110
00:44:43,520 --> 00:44:45,943
这对它们的后代来说可能是个死亡陷阱。

1111
00:44:50,630 --> 00:44:52,590
但这次的发展过程

1112
00:44:52,590 --> 00:44:53,993
看起来进展顺利。

1113
00:44:56,710 --> 00:44:59,923
到三月这个时候，最严重的霜冻已经过去。

1114
00:45:02,340 --> 00:45:05,803
蝌蚪们必须赶紧长大。

1115
00:45:29,160 --> 00:45:31,760
南部山脉的秃鹰，

1116
00:45:31,760 --> 00:45:34,120
从卡索拉到莫雷纳山脉，

1117
00:45:34,120 --> 00:45:36,660
还有蒙弗拉格国家公园，

1118
00:45:36,660 --> 00:45:39,620
察觉到了空气中的变化。

1119
00:45:39,620 --> 00:45:42,463
它们的荷尔蒙使它们的神经紧张。

1120
00:45:45,160 --> 00:45:49,620
最好的隐蔽巢穴，位于最佳位置的巢穴，

1121
00:45:49,620 --> 00:45:52,530
那些位于最平坦的地方，

1122
00:45:52,530 --> 00:45:54,990
那些在最陡峭的悬崖上

1123
00:45:54,990 --> 00:45:59,146
或是最容易到达的地方却受到严密防守。

1124
00:45:59,146 --> 00:46:01,896
（鸟鸣声）

1125
00:46:14,040 --> 00:46:17,140
可供选择的地方不多，

1126
00:46:17,140 --> 00:46:19,530
和庇护巢穴之间的区别

1127
00:46:19,530 --> 00:46:22,350
或一个够大或稳定，

1128
00:46:22,350 --> 00:46:24,130
而另一个不是，

1129
00:46:24,130 --> 00:46:26,793
对每只幼崽的生存至关重要。

1130
00:46:29,430 --> 00:46:31,793
最初几只已经孵化出来了。

1131
00:46:35,410 --> 00:46:39,690
这是最冒险的赌注，但如果它们能活下来，

1132
00:46:39,690 --> 00:46:42,623
它们将远远领先其它殖民地。

1133
00:46:45,790 --> 00:46:47,410
它们必须做好飞行的准备

1134
00:46:47,410 --> 00:46:49,423
当夏季炎热到来时，

1135
00:46:50,830 --> 00:46:53,640
许多动物因渴死时，

1136
00:46:53,640 --> 00:46:56,293
来喂养下一代鹰。

1137
00:46:57,370 --> 00:47:00,120
（鸟鸣声）

1138
00:47:30,161 --> 00:47:33,078
（鹤鸣）

1139
00:47:40,090 --> 00:47:41,970
冰常常使事情变得困难

1140
00:47:41,970 --> 00:47:44,603
今天鹤的饮水比较稀薄。

1141
00:47:46,680 --> 00:47:49,963
这再次表明一切很快就会改变。

1142
00:47:54,360 --> 00:47:58,820
这些鹤群在北方繁殖，从瑞典到俄罗斯，

1143
00:47:58,820 --> 00:48:00,640
秋天它们从哪里来

1144
00:48:00,640 --> 00:48:02,540
以及它们必须返回哪里筑巢。

1145
00:48:03,439 --> 00:48:06,356
（鹤鸣）

1146
00:48:33,400 --> 00:48:36,870
这些鸟类出现生殖焦虑的最初迹像

1147
00:48:36,870 --> 00:48:40,103
表示一切终于开始回暖了。

1148
00:48:40,940 --> 00:48:43,502
有些看起来高兴得发疯。

1149
00:48:43,502 --> 00:48:46,560
（调皮的音乐）

1150
00:48:46,560 --> 00:48:49,763
它们的仪式舞蹈形成了第一批交配伴侣。

1151
00:48:50,660 --> 00:48:52,693
它们可能会一起返程。

1152
00:48:55,150 --> 00:48:57,350
但以防万一，这也是个好主意

1153
00:48:57,350 --> 00:49:00,220
慢慢地互相了解，

1154
00:49:00,220 --> 00:49:02,470
因为当春天来临的时候，

1155
00:49:02,470 --> 00:49:03,783
它们该走了。

1156
00:49:53,844 --> 00:49:56,761
（鹤鸣）

1157
00:50:02,030 --> 00:50:06,080
今天是三月廿一日。春天。

1158
00:50:06,080 --> 00:50:07,973
连一只鹤也没有。

1159
00:50:09,620 --> 00:50:12,323
从理论上来说，未来几个月会有些疯狂；

1160
00:50:13,600 --> 00:50:17,320
多变的天气、不可预测的行为，

1161
00:50:17,320 --> 00:50:21,163
出生、进食、生存的迫切性。

1162
00:50:23,030 --> 00:50:26,060
这是一个新周期的开始

1163
00:50:26,060 --> 00:50:28,593
当植物王国和它的花朶苏醒的时候。

1164
00:50:30,800 --> 00:50:35,665
现在是交配、冒险和重新开始的时刻。

1165
00:50:35,665 --> 00:50:38,415
（激昂的音乐）

1166
00:50:44,460 --> 00:50:47,210
（雄伟的音乐）