大卫·艾登堡：大自然的声音 第2集英文字幕下载

　(ANIMALS HOOT AND CHATTER),The natural worldis filled with sound.,(THUNDERCLAP),But so far,we've been hearing only part of it.,(CHITTERS),(GROWLS),(CHIRPS)(BUZZES),New audio technology now capturessounds that we can't even hear.,(DEEP, RESONANT RUMBLING),For some animals,sound is the key to finding a mate...,(CHIRPS),...to impress others...,(CHIRPING, WHISTLING),(RUMBLING, POPPING),...and to warn off the competition.,(BELLOWS),(ANIMALS CHIRP AND CALL),(TWEETS),(CHIRPS, CHITTERS),(SINGS),(BIRDS CHIRP AND WHISTLE),(SINGS, CHIRPS),A British woodland in spring.,The air is filledwith the sound of bird song.,It's a sound that bringsa lot of people a lot of pleasure...,including me.,And all these birdsare singing for two reasons...,one - to establish a territory,,and two - to attract a mate.,(BIRDS SING AND CHIRP),Song travels wellin an open woodland.,But making yourself heard can be morechallenging in a noisier environment.,And there is one creature herethat has risen to that challenge.,This delightful little birdis a white-throated dipper.,For most birds of its size,,living beside streamsis rather a dangerous place.,Feathers, when they are wet,on a bird of this size,,aren't much good for flying,,but the dipperknows how to deal with that.,As it searches for foodbetween the rocks,,it stops frequently to cover itsfeathers with oil from a preen gland,so that they stay waterproof and dry.,Reaching your food underwater...,is just one of the problemsfaced by the dipper.,Another is how do you send messages,above the noise of the fast-flowingstream by which you live?,But the dipper has a wayof dealing with that as well.,It's the breeding season...,...and this male uses his voiceto find a partner.,(WATER RUSHING, SOFT CHIRPING),To our ears,his singing can hardly be heard,above the sound of the water.,But eliminatingthe sounds of the river,reveals a surprisingly complexand melodious song.,(ARTICULATED CHIRPS),Most of the dipper's notesare higher-pitched,than the noise of the water.,(MELODIC CHIRPING),This allows othersto hear his song more easily.,He has attractedthe attention of a female.,(ELABORATE CHIRPING),Only males in peak conditioncan sing complex tunes like this.,(SINGING),His song has impressed,,and his new mate will stay with himfor the rest of the year,and help him defend this territory.,(COMPLEX CHIRPING),Six weeks later,and the pair have been busy.,Concealed behind the waterfallis their nest.,To ensure a steady supply of foodfor the chicks,,the pair have to defendtheir stretch of river from others.,And its their songthat acts as a warning to rivals.,(SINGS),Together,they present a united front.,(SINGING),For any intruders,the message is loud and clear.,(ELABORATE CHIRPING AND SINGING),Keeping the chicks well-fedis crucial,,and not just for their growth.,It's needed to developthe part of the brain,responsible for learning song.,So, they will, one day,become proficient singers,,like their parents.,Two weeks on, and all three chickshave fledged successfully.,(CHIRPING),These youngsters have hadthe best possible start in life...,...thanks to their parentsand their song.,(SINGS),When it comes to finding a mate,,power, not melody,is sometimes needed.,(HIGH-PITCHED CALLS),(RESONANT CALLS AND GRUNTS),Autumn inthe Rocky Mountains of Canada.,(SNORTS),(HIGH-PITCHED CALL),This bugling call of the elkmarks the change of season...,and the beginning of the annual rut.,(DEEP VOCALISATIONS).
    This bull is in his prime,and over the next six weeks,,he will push himself close to deathin order to mate.,The females will only acceptthe largest and strongest male.,And his success will depend onthe power of his voice.,Stretching his vocal chords,,he produces a high-pitched shriekthrough his nose.,It travels over a mile...,and announces his presenceto distant females.,(BELLOWS),At the same time,he makes a guttural groan...,(RESONANT BELLOW),...which signals his size and strengthto nearby males.,The deeper his voice,the bigger and stronger he is.,And he backs it upwith a physical display.,(BELLOWS, CALLS),His goal is to gatheras many females as possible...,to ensure that his genesare the ones that are passed on.,(BLEATING),(HIGH-PITCHED CALL),(DEEP, RESONANT VOCALISATIONS),Now he switchesto a different call...,(VOCALISATION CONTINUES),...a low 'glunking' soundto encourage the females to join him.,A successful bull can attractup to 20 females in one season.,(DEEP VOCALISATIONS),Chemical cues,detected with his tongue,,tell him which cows are fertile.,But retaining so many femalesis easier said than done.,(HIGH-PITCHED CALL),A rival enters the arena.,(BELLOWING),Their bugles signalthat they are equally matched.,There's only one way to settle this.,He must stand his groundor surrender his females.,These battles can resultin serious injury, even death.,(HIGH-PITCHED CALL),For the moment, at least,,his legacy is secure.,(RUMBLING),(RUMBLING),On the vast grasslands of Alberta,,it takes teamwork to get noticed.,(COOING),(RESONANT RATTLING),Every spring,,male sharp-tailed grouse gatheron traditional breeding grounds...,(RATTLING),...practising for their most importantperformance of the year.,(CLUCKING, RATTLING),And they have a remarkable array,of musical instrumentsat their disposal.,Feet are stamped,,and tail feathers rattled,to produce a rhythmic beat.,A low cooing sound,,amplified by inflatable air sacs,,provides the accompanying tune.,(CLUCKING, RATTLING),And it's all to attract the attentionof the females.,The more males, the louder and moreimpressive their performance.,(COOING, RATTLING),But sometimes, tensions boil over.,(CLUCKING),They need to stop squabblingand work together.,(RATTLING),Their combined song and dancehas attracted a female.,(CLUCKING),Time for the synchronised finale.,They all freeze.,She takes the opportunityto assess each male.,(RATTLING RESUMES),Now she's looking forthe fastest tail rattle.,And a soundlike the popping of a cork...,(POPPING),...which females find irresistible.,Their display will help her findthe fittest male in the group.,And this onehas caught her attention.,But not everyoneis sticking to the dance routine.,A young, over-enthusiastic male,is ruining the performancefor everyone.,(CLUCKS),She's seen enough.,And she's off.,(RATTLING),Today didn't go as planned.,(CLUCKS),But tomorrow, they'll havethe chance to do it all over again.,While grousebenefit from joining forces,,others must find a wayto stand out from the crowd.,(HIGH-PITCHED SHRIEKS),In the deserts of Arizona,,temperatures can soarabove 40 degrees Celsius.,Rain hasn't fallen herefor several months.,But things are about to change.,(THUNDER RUMBLES),(WIND HOWLS),(CRACKLES),(THUNDERCLAP),(THUNDERCLAP),Within hours,the rains flood the ground...,and temporary pools appear.,The thunder sends shockwavesthrough the ground...,(THUNDERCLAP)......