評論
打印
Snowy owls make their summer nests north of the Arctic Circle on high ground.
雪鸮把它們夏季的巢穴建在北極圈北部的高地上。
Their plumage changes little with the seasons and their nests are easy to spot against the exposed tundra soil.
它們的羽毛幾乎不隨季節(jié)而變化，而它們的巢穴在苔原上裸露的泥土映襯下極易被識別。
This female has ten eggs to protect. Her plumage is darker and more mottled than the males.
這只雌性有十只卵需要保護，它的毛色比雄性略深斑點也略多些。
Some tundra animals do change with the seasons. This arctic hare's upper body will darken for the few short weeks of summer.
有些動物的確會隨季節(jié)而改變，這種北極野兔的上半身毛色會在夏季短暫的幾周里變得稍暗。
In places, the growing season lasts just six weeks, so the plants here have had to adapt.
在有些地方，生長季僅僅會持續(xù)六周時間，所以這里的植物必須適應。
This explosion of life attracts a massive gathering of migration birds.
這種暴發(fā)式的生態(tài)繁榮引發(fā)了候鳥的大量聚集。
In spring, hundreds of millions of birds make the annual trip to the arctic tundra.
舂天里，數以億計的鳥類像往年一樣踏上了前往北極苔原的旅程。
But one species, the arctic tern, flies to northern Europe all the way from the Antarctic. No animal on earth migrates this far.
而有一種鳥類，北極燕鷗，卻從遙遠的南極洲一路飛抵北歐，地球上沒有任何動物能遷徙這么遠。
Its annual trip of seventy thousand kilometers means it will fly nearly two million kilometers in its lifetime.
它們一年一度的旅程長達七萬公里，這意味著每只鳥一生中的飛行旅程長達將近兩百萬公里。
And the reason that terns fly so far to these wetlands lies just below the surface.
燕鷗不遠萬里飛來這片濕地的原因就隱藏在這水面之下。
As the pools warm from the extra sunlight, insects are hatching.
水潭隨著太陽光照的增強而變暖，昆蟲因此得以孵化。
Right across the tundra, billions of mosquitoes are hatching.
整個苔原上，幾十億只蚊子開始孵化。
It's what the birds have been waiting for.
這正是鳥兒們所期待己久的。
But even a billion birds can't cope with this many mosquitoes.
然而即使這數以億計的鳥類也無法對付如此多的蚊子。
The insects form vast swarms and head off in search of the meal.
昆蟲大量匯集成群，飛到各處尋找食物。
In Alaska, the emergence of the mosquitoes coincides with the arrival of the porcupine herd.
在阿拉斯加，大量蚊子孵化時恰逢格蘭特馴鹿剛剛抵達。
They finally completed their epic migration to take advantage of the lush vegetation.
它們好不容易完成了史詩般的旅程，正打算享用豐美的青草。
But the presence of the mosquitoes makes the tundra this time of the year one of the most inhospitable places on the planet and the herd must keep moving in search of respite.
但是蚊子的出現卻把此時的苔原變成了地球上最不適宜居住的地方，而馴鹿群也不得不繼續(xù)前行尋找棲息之地。
Once this massive reindeer herd is in motion, not even the hundreds of fast flowing melt water rivers can stand in their way.
一旦這一大群的馴鹿行動起來，那幾百條河流中湍急的融冰之水也無法阻擋它們的腳步。
The reindeer can swim amazingly fast, up to ten kilometers an hour.
馴鹿游水的速度驚人，可以高達每小時十公里。
For many of the calves, this will be the first time they cross the river so big.
對很多小鹿來說，這將是它們首次跨越這么寬的河流。
The herd may have shaken off the mosquitoes, but crossing the river comes at a price. And some gets separated.
馴鹿群也許可以藉此擺脫蚊蟲的糾纏，但過河也會付出代價，而有些馴鹿掉隊了。
