南侨治亚岛.doc

1、The Living Edens: South Georgia Island南喬治亞島The edge of the Antarctic.Your nearest neighbouris nearly fourteen hundred kilometres away.And its cold- very cold.You are surrounded by wild ocean-thats bursting with life.One of the harshest rocks on earthsits in one of its richest seas-its a magnet for m

2、illions of animalsall across the southern oceans.They come here to feedand breed on a scalethat defies the imagination.This is South Georgia Island-paradise of ice.Humans never settled on South Georgia Island.It sits over two thousand kilometreseast of the furthest tip of South America-a lonely, sto

3、rm-lashed outpostand paradise for wildlife.Imagine the heart ripped out of the Alpsand hurled into the Southern Atlanticand you get the idea of the scaleof the island.South Georgia is just north of Antarcticato be marginally warmerand the waters rarely freeze.But in winter, at sea level,air temperat

4、ures will drop to fifteen degreesbelow zero. Gales top a hundredand fifty kilometres an hourand few places are as hostile and unwelcoming.It should be blasted free of life.but its not.Very few can survive these conditions,but some, with remarkable adaptation,manage to stay the course of winter-these

5、 are king penguins.Practically every day, throughout the year,hundreds of these parent birdsreturn from the sea to make the long trekinto the hills to feed their chicks,huddled together for warmthhidden in the shelter of a mountain bowl.There are over ten thousand chicksin this colony- nearly half a

6、 millionon the island, for the most part,along South Georgias more shelterednorth coast.Instinct means the parents have no choicebut to battle the elementsin a relentless search for food.Its not only parent penguinscompelled to hunt in this way.A wandering albatross takes on the worstof the southern

7、 Atlantic ocean.After days at sea, it is also returningto feed its hungry chickbut unlike the penguinsthis one sits quietly on its own in its nest.The parents fly over thousandsof square kilometres to find food,so the chick waits alonethrough the long winterfor their return visits to feed it-it will

8、 be many months yetbefore it can leave the nest.At almost a metre tallthe king penguin is the second largestafter the Emperor, but its breeding cycleis longer. From the day the egg is first laid,it takes an extraordinary fourteen monthsuntil the chicks are grown;which means the parents cant breedat

9、the same time every year.Some parents breed early in the seasonand some lay late but the aimseems to be for the chicksto join the adults in the summer monthswhen food is plentiful. The downsidefor the late chicks is thatthey have less time to preparefor the cruel Antarctic winter.And for their paren

10、tsthere is the seemingly endless taskof keeping their chicks fedthrough the worst of the winter;which may last more than three months.The adults regurgitate partially digested fishand squid directly into the chicks mouths.The chicks are well insulatedfrom freezing cold with their fluffy brown down-p

11、enguins get a lot of their insulationfrom air trapped in their dense plumage,so its greatest threat is not the snowbut wind chill. Year round,South Georgia is battered by terrible gales.Wind chill will drive temperaturesdown to minus seventy degrees.To have any chance of survival,the chicks must hud

12、dle tightly togetherfor shelter. In the depths of winter,many parents just cant keep coming with foodand their chicks survive offtheir energy-rich blubber.If they have to, they can lastmore than three months between mealsbut they will lose upto half their body weight.The colony is constantly on the

13、movewhich means no chick stays too longin the warmer center of the huddle.They all end up taking their shareof the punishing weather.For the adults there is no chance of shelterin a huddle.They must keep returning to the sea;without the wind-chillits warmer than the landand they need to feed themsel

14、ves.Not surprisingly, king penguinsare excellent swimmers and can divefor around 10 minutes,and to depths of 300 metres.The adults fish in groups;keeping themselves well feduntil the weather lets themreturn to their chicks again.Their porpoise-like leapsare fast and efficient; saving them energyin t

15、he freezing waters.Another effortless moveris the wandering albatross;South Georgias only otherresident winter breeder.Its chick has to survive the worstof the storms completely alone.The wandering albatross has the largest wingspanof any seabird- over three metres tip to tip.Their flight is so effi

16、cientthat they barely need to flap their wingsas they soar thousands of kilometresin search of food.After days at sea one of its parentsis bringing back a huge meal in its gullet.The chick taps at its beakto stimulate delivery.It takes a full twelve monthsto raise the chick, and the parentsfind it s

17、o demanding that wanderersonly breed once every two years.In the gap year they often migratelong distances, some travellingthe entire circumference of the Earth.The desolation of the South Georgia winteris disrupted by a twice-daily commotion.Gentoo penguins. Like commutersreturning from work, every

18、 evening,on a handful of beaches,they appear by the thousand-wave after wave returning from feedingat sea. Over one hundred thousand pairscall this solitary island home.Remarkably, penguins share the same ancestoras the albatross- one a master of the oceanthe other a master of the skies.This is “rus

19、h hour“ on South Georgia Island.Thousands hurrying to get home before sunset.Theyre only here for the night-anxious for rest and security-this is one of only a few safe sanctuariesfor thousands of kilometres around.Leopard seals have a taste for penguins. Their presence in the bay causes panic-they

20、are fast swimmers. The gentoosare the fastest swimming bird in the world-but they are not as quick on landand there is a bottleneck on the beach.Within an hour, over thirty thousand penguinsmake it past the seals, and late arrivalsare forced to weave their waythrough the crowded beach,and up a steep

21、 hillside,walking almost a kilometreto find a space to restbefore the sun finally sets.Dawn the next morning and all the commutersare ready to go back to sea.But there seems to be a reluctanceto take the first cold plunge.Eventually, its pressure from behindthat starts a domino effectof departing bi

22、rds.Within just half an hour,thirty thousand gentoos disappear.September- the beginning of springin the southern hemisphere.Hormonally charged male southern elephant sealsstart returning to breed after months at sea.Its thought that the malesstay close to the island in winterbut the females may trav

23、elup to 3000 kilometres into the Southern Ocean.Weighing up to four tonnes,the bulls have no trouble muscling inon the king penguins winter beaches.This is the calm before the storm;the beach will soon be a battlefield of malesfighting over females. Early arrivalsare quickly commandeered-“possession

24、 is nine tenths of the law“,it seems to apply to natural law too.In this battle for sexual success,territory is all. And the maleswill throw everything into the fightfor prime position on the beach.Their weight and teethare their punishing weapons.Eventually, one exhausted male retreats.Soon after t

25、he males, large numbersof smaller females start returningto the island.Within just a week or so,the once deserted beach is thickwith four thousand seals.Its now that the successful malescan claim their prize.All the hundred or so femalesaround this male form his harem.His sole aim is to mate with th

26、em,once they give birth.The pups are born immediately,they are the result of matingon the same beach last year.There are just twenty-one days to nursebefore their mothers are sexuallyreceptive again.Now more than ever, the males must fightto protect their harems. Giant bullscan be up to six metres l

27、ong,and weighing almost 4000 kilogramsthey can inflict serious damage.This really is survival of the fittest-the most powerful and aggressive bullscarry the scars of fightingon their head and neck.One finally admits defeatand retreats defensively;bloodied and bruised.More than half of the worldsesti

28、mated 600,000 southern elephant sealslive on South Georgiaand for the king penguins,these intruders are a real inconvenience.Somehow they manage to squeeze their waythrough this wall of noisy blubber.Only a third of the male elephant sealsmanage to claim harems on the beach,and the females are still

29、 freeto switch harems if they choose.Most of the would-be contendersare forced to idle in the surf.But they are not beyond trying:they intercept females as they come and gofrom the beach, but they are luckyif they get away with it,and all the females will soon be mated.By the end of October, most of

30、 the elephant sealbattles are over and the beaches fall quiet.Our wandering albatross chick,now eight months old, survived the winterto see the spring arrive.Longer, warmer days begin to thaw the island.After months in monochrome,South Georgia finally reveals the green faceof its gentler, more prote

31、cted north shore.Including the penguins, 30 million birdsnest and bring up chickson South Georgia each year-twice the population of Beijing.And the north shore is the favourite placefor breeding seabirds to set up homeeach summer. Other albatrossesnest here as well as the wanderer,including the smal

32、ler light mantledsooty albatross. The males come in first,scouting for suitable nest ledges.Once a site is found, he tries to attractpassing females with his plaintive call.When her choice is made, the male will join herin an exquisitely synchronisedcourtship flight- each birdbeautifully mimicking t

33、he movement of the other.Albatrosses can only nestwhen the snow is gone, only the king penguinshave found a way to incubate eggson the ice here. So the restof the islands breeding birdslook for sites on recently exposedrocks and grass.These are black-browed albatrosses,about half the size of the wan

34、derers.They feed largely on krill-a type of free-swimming shrimp,while the similar grey-headsspecialize in squid. About 80 000 pairsof grey-heads breed here-South Georgia is one of the very few optionsthey have; to the east the nearest islandsare about 10 000 kilometres away,after that its Australiaand New Zealand.South Georgias harsh south coastattracts a spring arrival more at homein the frozen heart of Antarctica.Snow Petrels. They are highly manoeuvrableseabirds which feed on small fish.South of here they can be seen in flockson icebergs floating in the ocean.