0:01:07 > 0:01:11The pounding surf of the Great Southern Ocean beating on the rocks of South Georgia.
0:01:11 > 0:01:16Few creatures, you might think, could survive it.
0:01:16 > 0:01:20But macaroni penguins are desperate to get ashore.
0:01:35 > 0:01:39Their flippers are of little help out of water.
0:01:39 > 0:01:43All they have to give them a grip on these slippery rocks
0:01:43 > 0:01:47are the small claws on their feet.
0:02:03 > 0:02:10Now, at the end of summer, life is becoming increasingly difficult for these macaroni penguins,
0:02:10 > 0:02:16struggling to feed chicks that are almost fully grown and have massive appetites.
0:02:16 > 0:02:21With autumn coming, the weather will worsen.
0:02:21 > 0:02:26Massive depressions rush around the fringes of the Antarctic continent,
0:02:26 > 0:02:30creating gales that gust to 100 miles an hour and lash the sea into a frenzy.
0:02:30 > 0:02:36Soon temperatures will drop to below freezing and all the wildlife of Antarctica
0:02:36 > 0:02:43will run a desperate race to complete breeding before the ice closes everything down.
0:02:48 > 0:02:52In the deep south, the sea stays frozen all summer.
0:02:52 > 0:02:59The penguins here face an even greater challenge, for this is where the door closes first.
0:02:59 > 0:03:04Here at Cape Royds, I'm 1,400 miles closer to the Pole
0:03:04 > 0:03:11and this Adelie colony is the most southerly nesting group of any penguins anywhere.
0:03:11 > 0:03:18The summer here is very short indeed and these penguins must breed very swiftly if they're to be successful.
0:03:18 > 0:03:21They're well ahead of the macaronis up in the north
0:03:21 > 0:03:26and the chicks are already losing their down.
0:03:26 > 0:03:34Beneath the woolly coat lies the waterproof layer of feathers that will protect them in the icy seas.
0:03:40 > 0:03:45The season is so short that things have to move fast.
0:03:45 > 0:03:49Over a mere two weeks, the jam-packed colony virtually empties
0:03:49 > 0:03:56as the newly-feathered young follow their parents down to the sea for their first encounter with water.
0:04:08 > 0:04:12And their first swim will not be easy.
0:04:12 > 0:04:17The bay is filled with surging, sharp-edged brash ice.
0:04:17 > 0:04:22Even getting down to the water poses problems.
0:04:26 > 0:04:30Soon, the edge of the sea is thronged
0:04:30 > 0:04:37by apprehensive youngsters nervously waiting for someone to take the plunge.
0:04:37 > 0:04:43The brash is so thick and extensive that on its seaward side,
0:04:43 > 0:04:47adults returning with food for their chicks can't get through.
0:04:58 > 0:05:00They turn back.
0:05:08 > 0:05:11The hungry chicks have no choice -
0:05:11 > 0:05:14they have to get to sea to feed.
0:05:19 > 0:05:24It's easier for them to cross the brash than for their parents.
0:05:24 > 0:05:27Being much lighter and more buoyant,
0:05:27 > 0:05:33they can skitter across the surface of the broken ice.
0:05:41 > 0:05:45But moving so slowly and so clumsily
0:05:45 > 0:05:48puts them in real danger.
0:05:50 > 0:05:53WARNING CRY
0:05:58 > 0:06:00A leopard seal!
0:06:11 > 0:06:17The majority of the chicks make it to open water, where they're a little safer.
0:06:17 > 0:06:22The leopard seal stays with its victim.
0:07:16 > 0:07:21This game of cat and mouse goes on for 20 minutes.
0:07:21 > 0:07:26Like so many other large predators on land and on sea,
0:07:26 > 0:07:31the leopard seal seems to feel no urgency to complete its kill.
0:07:33 > 0:07:36At last, the penguin is dead.
0:07:37 > 0:07:42Now the process of stripping off its flesh begins.
0:08:12 > 0:08:16The carcass drifts down to the sea floor
0:08:16 > 0:08:19but it won't be wasted.
0:08:36 > 0:08:38A nemertean worm, a metre long.
0:08:38 > 0:08:45It has detected the taste of penguin flesh drifting through the cold water.
0:08:53 > 0:08:56Another scavenger arrives -
0:08:56 > 0:08:59a giant isopod, 10 centimetres long,
0:08:59 > 0:09:03the equivalent of crabs in warmer waters.
0:09:11 > 0:09:16The isopod strips off the meat with its hooked legs and strong jaws.
0:09:16 > 0:09:21The worm turns its stomach inside out and envelops the food.
0:09:23 > 0:09:29Within hours, the carcass is covered by a writhing tangle of worms.
0:09:32 > 0:09:37Within days, there is nothing left but bare bones.
0:09:40 > 0:09:45The first snows of winter have fallen.
0:09:45 > 0:09:52The last chicks to hatch are doomed. Their parents have to abandon them before they're fully grown.
0:09:52 > 0:09:57The adults must go to sea to build up their strength
0:09:57 > 0:10:04before returning to the colony for one last ordeal before winter sets in - the moult.
0:10:04 > 0:10:11All penguins need a new coat of feathers for the winter.
0:10:11 > 0:10:18That means shedding the old one. Colonies across the continent fill with shed feathers.
0:10:18 > 0:10:25On Deception Island, chinstrap penguins stand silent and motionless.
0:10:30 > 0:10:35Only a month ago, these steep slopes of volcanic ash
0:10:35 > 0:10:42were noisy with the squawks of 80,000 pairs of them coming and going and caring for their chicks.
0:10:42 > 0:10:46Now, they've little energy to spare.
0:10:46 > 0:10:53They can't go to sea with their coats in this condition, so they can't feed.
0:10:56 > 0:11:01For three weeks they stand fasting, losing half their body weight
0:11:01 > 0:11:08but at the end they'll have warm, watertight coats and be ready for the icy blasts of winter.
0:11:14 > 0:11:18By the end of March, most of them have left
0:11:18 > 0:11:21and the remainder are on the move,
0:11:21 > 0:11:27making their way across the emptying slopes, back to the sea.
0:11:49 > 0:11:53Escape to the north, to open seas, is the driving force -
0:11:53 > 0:11:57to move where the food should be.
0:11:57 > 0:11:59But the obstacles are formidable.
0:12:24 > 0:12:30At minus 1.9 degrees centigrade, the sea begins to freeze.
0:12:30 > 0:12:34A slight swell on the surface produces pancake ice.
0:12:40 > 0:12:45In the frigid air, the ice above water grows into crystals.
0:12:46 > 0:12:52The early explorers called these fantastic shapes "ice flowers".
0:12:58 > 0:13:03As it gets colder and colder, the ice thickens.
0:13:03 > 0:13:08On the coast, it freezes fast to the margins of the land.
0:13:11 > 0:13:15Farther out, the pack-ice consolidates into sea-ice.
0:13:15 > 0:13:20The belt of ice surrounding the continent widens,
0:13:20 > 0:13:25advancing northwards two miles a day and driving life before it.
0:13:27 > 0:13:32But the ice front has not yet reached all the islands
0:13:32 > 0:13:39and there are still some that can provide a refuge for wildlife well into autumn.
0:13:44 > 0:13:50Here on South Georgia we are on the northern edge of Antarctica.
0:13:50 > 0:13:56The sea here doesn't usually freeze over. Only once or twice in a century does it do so.
0:13:56 > 0:14:01This floating ice has all fallen from the glacier behind me.
0:14:01 > 0:14:09But although at 54 degrees south we are as far away from the South Pole as Britain is from the North,
0:14:09 > 0:14:14the immense ice-cap of Antarctica still dominates the climate.
0:14:14 > 0:14:17Glaciers cover over half the island.
0:14:17 > 0:14:20They blanket many of the peaks,
0:14:20 > 0:14:24the tallest of which are 2,700 metres high,
0:14:24 > 0:14:28and in some places they run right down into the sea.
0:14:28 > 0:14:34During winter, the temperature falls to minus 10 degrees at the coast,
0:14:34 > 0:14:41so the need for animals to complete their breeding in the short summer season is still very intense.
0:14:43 > 0:14:46Two million fur seals breed here
0:14:46 > 0:14:53and at the end of summer, the beaches are thronged with young pups and their mothers.
0:14:53 > 0:14:58The pups suckle for 4 months, until late March.
0:14:58 > 0:15:03That's longer than fur seals that live in warmer waters farther north.
0:15:03 > 0:15:10It's a measure of how strong young animals have to be to survive down here.
0:15:16 > 0:15:20A pup, if it is to get all the milk it's due,
0:15:20 > 0:15:26has to recognise its mother's call when she returns from feeding at sea
0:15:26 > 0:15:29and is ready to provide a feed.
0:15:32 > 0:15:35CALLING TO PUP
0:15:40 > 0:15:45Three months earlier, this shore was a battlefield
0:15:45 > 0:15:52as bulls fought for the right to dominate a stretch of beach - and all the females on it.
0:15:52 > 0:15:56Now the mating has finished and the bulls have gone to sea.
0:15:56 > 0:16:01The pups are left to test their strength with MOCK fights.
0:16:50 > 0:16:55Many of the youngsters playing here will not survive their first year.
0:16:55 > 0:16:59The weaker ones will not get enough food.
0:16:59 > 0:17:05There will be accidents and orphans. By the end of the breeding season,
0:17:05 > 0:17:10corpses lie scattered over the beach - food for skuas and giant petrels.
0:17:40 > 0:17:45The petrels with their great, hooked beaks,
0:17:45 > 0:17:50are usually the first to rip open a carcass.
0:17:50 > 0:17:57They are the Antarctic's equivalent of Africa's vultures. Their huge wings are 2 metres across.
0:17:57 > 0:18:01But unlike vultures, they don't just scavenge.
0:18:01 > 0:18:06They tackle young penguins and small sea-birds while they're still alive.
0:18:33 > 0:18:39The whalers in the old days used to call them "gluttons".
0:18:39 > 0:18:46It's easy to see why. Their dirtiness gave them another name - "stinkers".
0:18:46 > 0:18:50Surprisingly, there are ducks at this feast too.
0:18:50 > 0:18:53These are South Georgia pintails.
0:18:53 > 0:18:59Alone among ducks, they've acquired a regular taste for meat.
0:19:35 > 0:19:39An elephant-seal wallow. This is an all-female gathering.
0:19:39 > 0:19:46They clearly like one another's company, for they congregate in great assemblies.
0:19:46 > 0:19:52That doesn't mean they don't, on occasion, get irritated with one another.
0:19:54 > 0:19:58GRUNTING NOISES
0:19:58 > 0:20:04Like the penguins, they went to sea after rearing their young,
0:20:04 > 0:20:11fed intensively to put on the weight they lost during breeding and now they've come back in order to moult.
0:20:16 > 0:20:21Large chunks of skin and hair peel off their bodies
0:20:21 > 0:20:23and it seems to make them tetchy.
0:20:23 > 0:20:28It takes a month for them to grow new coats.
0:20:28 > 0:20:33Then, as the temperature falls still lower and winter closes in,
0:20:33 > 0:20:39they will return to the place where they are most at home - the sea.
0:20:42 > 0:20:47Grey-headed albatross also nest on South Georgia
0:20:47 > 0:20:50but they stay a little longer.
0:20:51 > 0:20:54The waters are still ice-free,
0:20:54 > 0:20:59so they can catch food for their young well into autumn.
0:21:18 > 0:21:21An adult bird, caring for its chick,
0:21:21 > 0:21:27may travel 600 miles or more to find food, which it brings back in its crop.
0:21:37 > 0:21:39That was a squid
0:21:39 > 0:21:42and very nice too.
0:21:43 > 0:21:48Above the grey heads, another kind of albatross -
0:21:48 > 0:21:55the largest sea-bird in the world, with a 3-metre wingspan, the wandering albatross.
0:21:55 > 0:22:02It nests a little further inland on South Georgia's meadows and ridges of tussock-grass.
0:22:07 > 0:22:11In marked contrast to the other birds,
0:22:11 > 0:22:15that have almost finished their breeding and are preparing to leave,
0:22:15 > 0:22:22this wandering albatross has come to start a courtship that may take two or three years.
0:22:26 > 0:22:32SHRILL CRIES
0:22:32 > 0:22:39These young birds have spent the first three years of their adult life at sea.
0:22:39 > 0:22:47Now they've returned to the colony where they were reared and are looking for a partner.
0:22:47 > 0:22:52And the way they do this is by taking part in dancing parties.
0:23:13 > 0:23:18Young, unmated birds court like this for several years
0:23:18 > 0:23:22before they decide who their partners shall be
0:23:22 > 0:23:27and together start work on a nest mound.
0:23:40 > 0:23:44But as the winter sets in and its icy door closes,
0:23:44 > 0:23:49the young albatross too have to return to sea.
0:24:19 > 0:24:23The sea won't freeze here around South Georgia
0:24:23 > 0:24:28but as the sun moves north and the days darken,
0:24:28 > 0:24:35the temperature of the ocean falls lower still and life in the water becomes increasingly scarce.
0:24:35 > 0:24:42The shoals of krill disperse and for sea-birds, food becomes more and more difficult to find.
0:24:51 > 0:24:58By April, winter storms are beginning to sweep across the Antarctic.
0:25:21 > 0:25:27The winds rise to above 100 miles an hour.
0:25:27 > 0:25:32The temperature falls to 70 degrees below zero.
0:25:35 > 0:25:37And then, the sea freezes.
0:25:37 > 0:25:40The door has shut.
0:25:42 > 0:25:47Throughout the winter, the ice continues to advance northwards.
0:25:47 > 0:25:54The area it covers increases at the rate of 40,000 square miles every day.
0:25:54 > 0:26:01Before the winter is over, it will have almost doubled the size of the continent.
0:26:31 > 0:26:38Now, at the end of autumn, practically all the wildlife has escaped to the north.
0:26:38 > 0:26:42The whales have gone to find warmer waters in which to breed.
0:26:42 > 0:26:50The seals, albatrosses and most of the penguins have also gone out to sea, though no-one is sure where.
0:26:50 > 0:26:58But there is one truly remarkable creature that turns all these rules upside down - the emperor penguin.
0:26:58 > 0:27:01Largest of all the penguins,
0:27:01 > 0:27:05the emperor stands over a metre high
0:27:05 > 0:27:08and weighs, on average, 33 kilos.
0:27:08 > 0:27:15Most creatures are forced by the worsening weather to retreat north to warmer latitudes
0:27:15 > 0:27:22but the emperors are gathering at the ice edge to start travelling into the deep south,
0:27:22 > 0:27:26where they will mate and rear their young.
0:28:06 > 0:28:11Now the emperors start their long march, maybe tens of miles,
0:28:11 > 0:28:14to reach their traditional nesting site on the sea-ice.
0:28:38 > 0:28:42Subtitles by Donna Jordan BBC Scotland 1993