0:00:07 > 0:00:08BELL TOLLS
0:00:08 > 0:00:10In the far west of America...
0:00:11 > 0:00:13..there's a legendary land.
0:00:15 > 0:00:17The haunt of cowboys...
0:00:18 > 0:00:22..and home to great Native American civilisations...
0:00:26 > 0:00:29..where the promise of gold drew those seeking their fortune.
0:00:32 > 0:00:35Here, over millions of years,
0:00:35 > 0:00:36powerful forces have forged
0:00:36 > 0:00:40some of the most dramatic landscapes on Earth...
0:00:42 > 0:00:45..from the continent's hottest deserts
0:00:45 > 0:00:47and red, rock canyons...
0:00:48 > 0:00:52..to towering mountain worlds cloaked in snow...
0:00:56 > 0:00:59..and the most mysterious and magical coastline.
0:01:04 > 0:01:11It takes a special breed with bold ambition and a pioneering spirit
0:01:11 > 0:01:16to tame this fabled place and make it home.
0:01:23 > 0:01:24The wild west.
0:01:35 > 0:01:38From the Sierra Nevada to the Rockies,
0:01:38 > 0:01:41great mountain ranges dominate the wild west.
0:01:46 > 0:01:48It was the hunt for new land,
0:01:48 > 0:01:53for furs and gold, that drew adventurous spirits
0:01:53 > 0:01:54to this rugged frontier.
0:02:05 > 0:02:07This is a world of extremes.
0:02:13 > 0:02:15Where winters are long and hard...
0:02:18 > 0:02:20..summers brief but plentiful.
0:02:25 > 0:02:27With the ever-changing seasons,
0:02:27 > 0:02:30life is a constant race against time
0:02:30 > 0:02:32in this wild mountain world.
0:02:48 > 0:02:51For six months, the high country has been in lockdown.
0:02:54 > 0:02:58Blizzards, deep snow and sub-zero temperatures
0:02:58 > 0:03:00make this hostile territory.
0:03:03 > 0:03:07But, for a few, these are the best of times.
0:03:14 > 0:03:17Coyotes prey on the victims of winter.
0:03:26 > 0:03:29Working as a pack, they could kill an elk...
0:03:32 > 0:03:34..but it's easier to let the cold do the work.
0:03:37 > 0:03:41Three-quarters of their winter food comes from scavenging carcasses.
0:03:56 > 0:03:57When their chance comes,
0:03:57 > 0:04:00ravens and eagles will quickly pick the bones clean.
0:04:04 > 0:04:08In the high country, survival depends on grabbing any opportunity.
0:04:21 > 0:04:24As winter begins to loosen its grip,
0:04:24 > 0:04:27a new world opens up in the mountains.
0:04:50 > 0:04:54From its source 12,000 feet up in Colorado's Ruby Range,
0:04:54 > 0:04:56Oh-Be-Joyful Creek is on the rise.
0:05:08 > 0:05:11A few weeks ago, this was frozen solid.
0:05:11 > 0:05:13Now, it's a raging torrent.
0:05:20 > 0:05:24At its peak, over 12,000 gallons of water funnel
0:05:24 > 0:05:26over these rapids every second.
0:05:55 > 0:05:56Woohoo! That rocked!
0:05:58 > 0:06:01There are dozens of cascades along the creek with names such as
0:06:01 > 0:06:04Ankle Breaker and Heart Attack,
0:06:04 > 0:06:07but this one is by far the biggest.
0:06:19 > 0:06:22It's the ultimate test of nerve and skill.
0:06:40 > 0:06:43Meltwater floods into thousands of creeks and rivers
0:06:43 > 0:06:45all over the wild west.
0:06:49 > 0:06:52This is a vast territory,
0:06:52 > 0:06:54bordered by two great mountain ranges.
0:06:56 > 0:06:59Towards the Pacific coast, the Sierra Nevada,
0:06:59 > 0:07:05a 400-mile-long chain of peaks rising to over 14,000 feet.
0:07:08 > 0:07:13And, far inland, beyond the great deserts, stand the Rockies,
0:07:13 > 0:07:171,000 miles of interconnecting ranges that divide the continent.
0:07:33 > 0:07:35Across all this high country,
0:07:35 > 0:07:38the increasing power of the sun is slowly drawing residents
0:07:38 > 0:07:40out from their winter refuges.
0:07:46 > 0:07:48Mountain goats are already on the move,
0:07:49 > 0:07:51shedding their thick winter coats along the way.
0:07:56 > 0:07:59After braving the winter snowed in on the high tops,
0:07:59 > 0:08:01they are heading down towards the forest...
0:08:03 > 0:08:06..and their first fresh food for months.
0:08:09 > 0:08:12Nanny goats gave birth before the thaw began...
0:08:13 > 0:08:15..giving their young the summer to grow strong
0:08:15 > 0:08:18before the winter cold returns.
0:08:25 > 0:08:28Yellow-bellied marmots have spent the whole winter asleep.
0:08:30 > 0:08:33That means a record eight months deep underground...
0:08:35 > 0:08:37..surviving only on their body fat.
0:08:43 > 0:08:45Not even a flood is going to keep a hungry marmot
0:08:45 > 0:08:47from the best grazing in town.
0:08:58 > 0:09:01Grizzly bears have also ventured out from their dens.
0:09:11 > 0:09:13They can lose a quarter of their body weight
0:09:13 > 0:09:14during the long hibernation.
0:09:17 > 0:09:18Summer for this family
0:09:18 > 0:09:23is all about packing on the pounds as quickly as possible,
0:09:23 > 0:09:25even if that means eating earthworms.
0:09:30 > 0:09:341,000 miles away, bathed in Sierra Nevada sunshine,
0:09:34 > 0:09:38high country giants are waking up after six months of winter.
0:09:47 > 0:09:53Sequoias are only found in these mountains, and at nearly 300ft tall,
0:09:53 > 0:09:56they are the world's biggest trees.
0:09:58 > 0:10:03Fireproof, rot proof, pest proof,
0:10:03 > 0:10:05they can live for thousands of years.
0:10:11 > 0:10:15The stringy bark makes perfect nest lining for a pair of tree creepers.
0:10:23 > 0:10:26Sequoia's roots often reach down only a few feet
0:10:26 > 0:10:29before they hit solid granite.
0:10:29 > 0:10:33To compensate, the roots grow horizontally,
0:10:33 > 0:10:34covering up to an acre.
0:10:39 > 0:10:42Interlaced with the roots of neighbouring sequoias,
0:10:42 > 0:10:44these giants are holding each other up.
0:10:49 > 0:10:53Living in their deep shadow isn't easy,
0:10:53 > 0:10:57but these strange plants have found a way.
0:11:00 > 0:11:03Snow plants have done away with the need for sunlight completely.
0:11:05 > 0:11:08Instead, they make their living as parasites.
0:11:11 > 0:11:14Their roots infiltrate those of their giant neighbours
0:11:14 > 0:11:17and they steal all the raw materials they need to grow.
0:11:22 > 0:11:25In turn, the snow plants provide for one of the forest's
0:11:25 > 0:11:27most unlikely residents.
0:11:32 > 0:11:35Anna's hummingbirds live in high country forests year-round.
0:11:43 > 0:11:45With few other flowers yet in bloom,
0:11:45 > 0:11:48this female depends on the snow plant's nectar for fuel.
0:11:53 > 0:11:56And the plants exploit this dependency.
0:11:59 > 0:12:01They need help spreading their pollen.
0:12:04 > 0:12:06Using nectar as a bribe,
0:12:06 > 0:12:11the plants ensure many visits from both female hummingbirds and
0:12:11 > 0:12:14brightly coloured males, who unwittingly collect pollen
0:12:14 > 0:12:16as they feed.
0:12:18 > 0:12:21As the birds move around the forest,
0:12:21 > 0:12:25they carry the pollen with them and so help fertilise the flowers.
0:12:36 > 0:12:39All this hovering can be exhausting.
0:12:44 > 0:12:48When a feisty rufous hummingbird tries to muscle in,
0:12:48 > 0:12:49things turn nasty.
0:13:15 > 0:13:17The smaller hummingbird is quickly run out of town.
0:13:19 > 0:13:22But he's already drained most of these flowers,
0:13:22 > 0:13:25so his attacker must move on.
0:13:29 > 0:13:33The snow plants will soon wither away as spring moves towards summer.
0:13:41 > 0:13:44In Yosemite Valley, granite cliffs rise vertically,
0:13:44 > 0:13:473,000 feet into the clear California sky.
0:13:58 > 0:13:59During the last ice age,
0:13:59 > 0:14:04this rock was gouged and sculpted by glaciers half a mile deep.
0:14:09 > 0:14:12Anything in their path was bulldozed aside.
0:14:14 > 0:14:16Whole mountains cut in half.
0:14:23 > 0:14:26Rivers of ice helped create this landscape.
0:14:26 > 0:14:28Now, meltwater is transforming it once again.
0:14:35 > 0:14:40Yosemite Falls plummet over 2,400 feet -
0:14:40 > 0:14:42the highest falls in North America.
0:14:54 > 0:14:56In just a few weeks,
0:14:56 > 0:14:59much of the high country has become green and welcoming.
0:15:00 > 0:15:05And that's the cue for one of the great wild west traditions to begin.
0:15:19 > 0:15:23For generations, ranchers have moved their cattle to summer pastures
0:15:23 > 0:15:25to fatten on the fresh grass.
0:15:34 > 0:15:37For Diane Bohna, boss of the 3Bar Ranch,
0:15:37 > 0:15:41the drive takes her from these parched Sierra foothills
0:15:41 > 0:15:44to the rich meadows high on Quartz Mountain.
0:15:49 > 0:15:51It's a journey she's made many times.
0:16:00 > 0:16:01I love the mountains.
0:16:01 > 0:16:05I've been going since 1968 with my father.
0:16:05 > 0:16:09We would go to the mountains in June and I would not come home
0:16:09 > 0:16:11until the night before school.
0:16:11 > 0:16:15I would see no-one all summer except the cows,
0:16:15 > 0:16:18the mountains and the animals and my family.
0:16:25 > 0:16:27Leroy is the lead bull,
0:16:27 > 0:16:30taking charge of the herd on the 70-mile trek.
0:16:40 > 0:16:46The steep, three-mile slog up Chowchilla Hill is thirsty work,
0:16:46 > 0:16:48the cattle always in danger from heat exhaustion.
0:16:56 > 0:16:59And now, having crested the hill,
0:16:59 > 0:17:02they must face a new, 21st-century challenge.
0:17:07 > 0:17:10Busy highways crisscross the old trail.
0:17:20 > 0:17:22Diane has to call the sheriff for help.
0:17:24 > 0:17:26Here, at least,
0:17:26 > 0:17:28the old ways still have priority.
0:17:42 > 0:17:44After three days on the road,
0:17:44 > 0:17:47the drive is about to enter a very different world.
0:17:49 > 0:17:52There is a transition that occurs.
0:17:52 > 0:17:56We will actually come around a turn, then you can see the pines.
0:17:57 > 0:18:01And once you see the pines, you can feel that cool breeze.
0:18:08 > 0:18:12Here, their route crosses streams fed with high country meltwater.
0:18:17 > 0:18:21It's a life-saver after the heat and dust of the first few days.
0:18:36 > 0:18:408,000 feet up, Leroy leads his herd into the meadows.
0:18:45 > 0:18:47Diane has got her timing spot-on.
0:18:47 > 0:18:50The grass is fresh, tall and sweet.
0:18:55 > 0:18:59These lush pastures will be home for the next three months.
0:19:02 > 0:19:06I feel my adrenaline dropping
0:19:06 > 0:19:09when I am on the fourth day of the cattle drive,
0:19:09 > 0:19:12because then I... We're home.
0:19:12 > 0:19:14I'm home.
0:19:20 > 0:19:22Not only do I do this now,
0:19:22 > 0:19:24my family does this.
0:19:24 > 0:19:28It is a family event to get the cows to the mountains...
0:19:30 > 0:19:35..to be able to pass on those traditions that I learnt
0:19:35 > 0:19:38when I was young to the future generations.
0:19:44 > 0:19:48My father used to tell me that you better love what you do,
0:19:48 > 0:19:50because you're not going to get rich doing it.
0:19:51 > 0:19:53This is what I love.
0:20:09 > 0:20:13In the Rockies, Yellowstone lakes are now full to the brim.
0:20:17 > 0:20:20Cut-throat trout are starting the most important few weeks
0:20:20 > 0:20:21of their year.
0:20:22 > 0:20:24As summer settles in,
0:20:24 > 0:20:27they leave the deep water where they spend the winter
0:20:27 > 0:20:29and head for one of the lake's feeder streams.
0:20:32 > 0:20:34Timing is everything.
0:20:34 > 0:20:37There's only a narrow window when the stream's flow and depth
0:20:37 > 0:20:39is just right for spawning.
0:20:43 > 0:20:46Competition for the best sites is fierce.
0:21:03 > 0:21:06Females dig scrapes in the stream bed,
0:21:06 > 0:21:08while the males stand guard,
0:21:08 > 0:21:10ready to fertilise the eggs as they're released.
0:21:14 > 0:21:17In the frenzy, the same gravel patches are disturbed
0:21:17 > 0:21:18again and again.
0:21:20 > 0:21:22And the eggs of previous nesters are swept away.
0:21:24 > 0:21:28So being the last to lay your eggs should be the best strategy.
0:21:31 > 0:21:34But the stream is a dangerous place to linger.
0:21:44 > 0:21:48This otter has timed its arrival to perfection.
0:22:01 > 0:22:03Using the bank as cover,
0:22:03 > 0:22:05the trap is sprung.
0:22:18 > 0:22:20With the otter preoccupied,
0:22:20 > 0:22:23those still in the stream make a run for it,
0:22:23 > 0:22:25back to the safety of deeper water.
0:22:48 > 0:22:51In the blazing summer sunshine,
0:22:51 > 0:22:54high country flowers are in full bloom.
0:23:04 > 0:23:07Bluebirds spend their winters far to the south,
0:23:07 > 0:23:09but have flown back to nest
0:23:09 > 0:23:10and enjoy the feast.
0:23:19 > 0:23:22Many summer visitors join the year-round residents
0:23:22 > 0:23:24to cash in on the bloom.
0:23:34 > 0:23:39With bears around, this is dangerous territory for mountain goats.
0:23:46 > 0:23:49But some have thrown caution to the wind,
0:23:49 > 0:23:52irresistibly drawn to the richness of these meadows.
0:23:55 > 0:23:57Although they never stray too far from the safety
0:23:57 > 0:23:59of a cliff-face retreat.
0:24:04 > 0:24:07Summer on the high peaks of the Rockies arrives weeks
0:24:07 > 0:24:08behind the meadows.
0:24:11 > 0:24:13Over 10,000 feet up,
0:24:13 > 0:24:17some summits are only now emerging from beneath the snow.
0:24:22 > 0:24:26This high-altitude world is where mountain goats are most at home.
0:24:29 > 0:24:31They struggle with the intense summer heat,
0:24:31 > 0:24:34so linger near the last snow patches to keep cool.
0:24:45 > 0:24:49This is the high country stripped back to its bare bones.
0:24:55 > 0:24:58There's never much to eat on these barren slopes.
0:24:59 > 0:25:02But living here puts the goats out of reach of all but
0:25:02 > 0:25:04the most determined predators.
0:25:20 > 0:25:24After several weeks on a largely vegetarian diet,
0:25:24 > 0:25:26these grizzly bears now feel the need for meat.
0:25:30 > 0:25:33They are heading two miles up, into mountain goat territory.
0:25:40 > 0:25:44But these bears are not here to hunt goats.
0:25:50 > 0:25:52Hundreds of thousands of army cutworm moths
0:25:52 > 0:25:55have flown here from distant valleys,
0:25:55 > 0:25:58attracted by the nectar of alpine flowers.
0:26:00 > 0:26:03During the day, they shelter from the heat in these boulder fields.
0:26:08 > 0:26:10It's like digging for gold.
0:26:15 > 0:26:17If they hit the jackpot,
0:26:17 > 0:26:19they can eat 40,000 in a single day.
0:26:27 > 0:26:32Each moth is 70% fat, so this binge feeding is a vital boost
0:26:32 > 0:26:34to the bears before hibernation.
0:26:36 > 0:26:38And at these rarefied altitudes,
0:26:38 > 0:26:40that may not be so far away.
0:26:46 > 0:26:49The Sierra Nevada range is the backbone of California...
0:26:52 > 0:26:53..crowned by Mount Whitney.
0:27:00 > 0:27:01Cold and windswept,
0:27:01 > 0:27:04some of these peaks are home to extraordinary trees.
0:27:07 > 0:27:09Bristlecone pines.
0:27:13 > 0:27:16Some have been alive for over 5,000 years.
0:27:17 > 0:27:20They're the oldest living things on Earth.
0:27:27 > 0:27:29It's so hostile here,
0:27:29 > 0:27:31the growing season only lasts a few weeks.
0:27:34 > 0:27:38The girth of these trees may have only increased by six inches
0:27:38 > 0:27:42since Columbus discovered the continent over 600 years ago.
0:27:48 > 0:27:53These ancient trees stand sentinel,
0:27:53 > 0:27:56as the seasons and the years sweep around them.
0:28:03 > 0:28:07But not everything in these mountains is so permanent.
0:28:20 > 0:28:23In 1859,
0:28:23 > 0:28:24gold was discovered here.
0:28:29 > 0:28:33A rough and lawless boom town quickly grew out of the wilderness.
0:28:49 > 0:28:52With 30 mines and 65 saloons,
0:28:52 > 0:28:57Bodie had a reputation for wickedness, for bad men,
0:28:57 > 0:28:59and the worst climate out of doors.
0:29:04 > 0:29:07Of the thousands of fortune hunters that rushed here,
0:29:07 > 0:29:08few struck it rich.
0:29:12 > 0:29:14When the gold petered out,
0:29:14 > 0:29:15the miners moved on.
0:29:18 > 0:29:21But today, Bodie isn't entirely abandoned.
0:29:23 > 0:29:26Pikas have moved in to stake their claim.
0:29:30 > 0:29:32Relatives of rabbits,
0:29:32 > 0:29:34they are obsessed by food.
0:29:39 > 0:29:42They must collect and store 50 times their own body weight of food
0:29:42 > 0:29:45in these mini haystacks before the winter returns.
0:29:52 > 0:29:54There's just one problem.
0:29:55 > 0:29:59With their thick coats, they can quickly overheat.
0:30:04 > 0:30:07So, they can only use the cool of the morning
0:30:07 > 0:30:10to gather grass and work on their hay piles.
0:30:13 > 0:30:17But always, the relentless sun is in hot pursuit.
0:30:26 > 0:30:31As shade shrinks away, they race to gather what they can.
0:30:41 > 0:30:43Just time for one last mouthful...
0:30:44 > 0:30:48..before high noon drives them into hiding, deep underground.
0:30:58 > 0:31:03The Bodie pikas aren't the only ones making hay while the sun shines.
0:31:19 > 0:31:226,000 feet up in Montana's Big Hole Valley,
0:31:22 > 0:31:26it's the start of a busy day on the Hershey Ranch.
0:31:38 > 0:31:43Heidi Hershey is the matriarch of the family and she runs the show.
0:31:43 > 0:31:46Usually the haying season is between
0:31:46 > 0:31:49the 15th of July and the 15th of August.
0:31:50 > 0:31:55Depending on the weather and...the breakdowns!
0:31:57 > 0:31:59The Hersheys only have a few weeks
0:31:59 > 0:32:01to cut and store enough grass to feed
0:32:01 > 0:32:05their cattle through a Montana winter.
0:32:05 > 0:32:10They rely on some antique, home-made machinery to help with the harvest.
0:32:12 > 0:32:16Buck rakes are used to gather great heaps of cut grass.
0:32:23 > 0:32:25Working as a team, they deliver
0:32:25 > 0:32:28tonnes of hay to this monster of a machine.
0:32:34 > 0:32:37It's called a beaver slide and it hoists the grass
0:32:37 > 0:32:40into a frame that shapes the stack.
0:32:57 > 0:33:02This is where the wild west meets the world of Mad Max.
0:33:09 > 0:33:13By dragging the cage forwards, huge hay piles 30 feet high
0:33:13 > 0:33:17and 100 feet long are built in double-quick time.
0:33:24 > 0:33:28They will build more than 50 stacks this summer.
0:33:31 > 0:33:37Each contains 20 tonnes of hay that can stay fresh for five years -
0:33:37 > 0:33:38more than enough to ride out
0:33:38 > 0:33:41anything a wild west winter can throw at them.
0:33:54 > 0:33:56High up in the Rockies,
0:33:56 > 0:34:00one of the greatest gatherings in the wild west is underway.
0:34:06 > 0:34:11For most of the year, bison bulls and cows live separate lives,
0:34:11 > 0:34:14but for a few weeks in late summer,
0:34:14 > 0:34:18thousands congregate in this Yellowstone Valley.
0:34:21 > 0:34:23It's the rut - the mating season -
0:34:23 > 0:34:29and the biggest bulls are busy guarding their harems.
0:34:29 > 0:34:32A dominant bull might mate with over 50 females.
0:34:39 > 0:34:41For the calves born this year,
0:34:41 > 0:34:44now is the time to stretch their young legs.
0:34:54 > 0:34:59But as the herd grows, so tensions rise.
0:35:07 > 0:35:11BELLOWING
0:35:28 > 0:35:31BELLOWING
0:35:39 > 0:35:43The rut takes a heavy toll on the big bulls,
0:35:43 > 0:35:48so arriving now could give this young contender an edge.
0:35:58 > 0:36:01But there's life in the old bull yet.
0:36:25 > 0:36:31Head-to-head, the challenger more than holds his own.
0:36:31 > 0:36:34Then, he makes a small mistake.
0:36:36 > 0:36:41Shunted aside, his challenge is brutally ended.
0:36:57 > 0:37:02The young bull gambled everything and has paid a heavy price.
0:37:02 > 0:37:05BULL BELLOWS
0:37:17 > 0:37:20As summer slips towards autumn,
0:37:20 > 0:37:23there is a late flourish across the high country.
0:37:25 > 0:37:28Many conifers are now covered in ripening seed cones.
0:37:31 > 0:37:34And they don't come much bigger than these.
0:37:37 > 0:37:42Over 18 inches long, sugar pine cones mature late in the season.
0:37:45 > 0:37:48Dripping with resin and packed with juicy seeds,
0:37:48 > 0:37:51they are on everyone's most-wanted list.
0:37:54 > 0:37:57Including forester John Pickett.
0:38:05 > 0:38:08There's a killer stalking these forests -
0:38:08 > 0:38:11an introduced fungus that's destroying the pines.
0:38:13 > 0:38:16A few resistant trees have been found here in California,
0:38:16 > 0:38:20so John gathers their cones and replants the healthy seeds.
0:38:28 > 0:38:32150 feet up, he collects the cones any way he can.
0:38:40 > 0:38:43None escape the long arm of the claw.
0:38:53 > 0:38:58It's easy to see why these 4lb cones are known as widow-makers!
0:39:05 > 0:39:09Standing under a sugar pine is not such a good idea.
0:39:15 > 0:39:19But for this Douglas squirrel, it's too good an opportunity to miss.
0:39:21 > 0:39:25And he's not the only one on the make.
0:39:38 > 0:39:42While he strips off the protective scales and carries each seed to his
0:39:42 > 0:39:45winter larder,
0:39:45 > 0:39:47he's being watched.
0:39:55 > 0:39:57Very closely.
0:40:07 > 0:40:11A Steller's jay doesn't miss a trick.
0:40:13 > 0:40:15There's buried treasure here,
0:40:15 > 0:40:19if the jay can pinpoint the squirrel's secret stash.
0:40:27 > 0:40:31This hoard is the squirrel's entire winter food supply,
0:40:31 > 0:40:34so he's not going to give it up without a fight.
0:40:40 > 0:40:43Time to run this seed rustler out of town.
0:40:58 > 0:41:01For this year, John's work is done,
0:41:01 > 0:41:03but it will be hundreds of years
0:41:03 > 0:41:07before the replanted seeds grow to match this forest giant.
0:41:20 > 0:41:25As winter edges ever closer, with the days shortening fast,
0:41:25 > 0:41:27the sun is losing its strength.
0:41:32 > 0:41:37Aspens urgently channel the last rays of useful sunlight into making
0:41:37 > 0:41:41a sugary antifreeze that will protect them from the cold.
0:41:52 > 0:41:56The green chlorophyll is withdrawn from the leaves.
0:41:56 > 0:41:59When everything useful has been reclaimed,
0:41:59 > 0:42:03the trees are ready to face the coming storms.
0:42:14 > 0:42:16With time running out,
0:42:16 > 0:42:20a young black bear is looking to put on a last few pounds.
0:42:25 > 0:42:28And this oak forest is his best chance.
0:42:31 > 0:42:36Acorns are full of energy, every one sniffed out is like gold dust.
0:42:38 > 0:42:41But he faces some stiff competition.
0:42:46 > 0:42:49Acorn woodpeckers have been busy.
0:42:50 > 0:42:54All this is the work of just one family.
0:42:57 > 0:43:01Some of the older larders may contain 50,000 acorns.
0:43:11 > 0:43:16As the acorns dry out, they shrink, so must be moved into smaller holes.
0:43:20 > 0:43:23The woodpeckers already have more than enough to see them through
0:43:23 > 0:43:26the winter, but they just can't stop themselves.
0:43:30 > 0:43:31And you never know what disaster
0:43:31 > 0:43:34might be lurking just around the corner.
0:43:38 > 0:43:41For the young bear, more serious competition has arrived.
0:43:45 > 0:43:49This bear has grown fat after a summer of gorging.
0:43:53 > 0:43:57Even so, he still wants all the acorns for himself.
0:44:04 > 0:44:08For the young bear, taking to the trees opens up a whole new world.
0:44:15 > 0:44:1960 feet up, there are acorns the bigger bears can't reach.
0:44:22 > 0:44:26And these fresh green ones are the most energy-rich of all.
0:44:40 > 0:44:44His acrobatics send down a shower of debris.
0:44:46 > 0:44:50A bonus for the big bear waiting on the ground.
0:45:01 > 0:45:03This might all be working out for the bears,
0:45:03 > 0:45:06but it's bad news for the woodpeckers.
0:45:06 > 0:45:09He's spotted one of their acorn larders.
0:45:31 > 0:45:34These are mostly old, dried-up acorns,
0:45:34 > 0:45:38but every little helps in the final rush to get ready for winter.
0:45:53 > 0:45:58With a full belly, the young bear finally comes back down to earth.
0:46:07 > 0:46:12Now all he needs is somewhere quiet to digest this last meal and to
0:46:12 > 0:46:15settle down for his big sleep.
0:46:19 > 0:46:21And not a moment too soon.
0:46:26 > 0:46:29A change in the wind, a storm shifts course
0:46:29 > 0:46:34and the greatest transformation of the year sweeps
0:46:34 > 0:46:36across the high country.
0:46:39 > 0:46:41Those that made the most of their opportunities
0:46:41 > 0:46:46are ready for this change and for the hard months that will follow.
0:46:56 > 0:46:59In the Big Hole Valley, the hay carefully stacked
0:46:59 > 0:47:02in the summer now feeds the Hersheys' cattle.
0:47:10 > 0:47:13Real horsepower is the only reliable delivery service
0:47:13 > 0:47:14when it's this cold.
0:47:26 > 0:47:30It will be another six months before these valleys are clear of snow.
0:47:35 > 0:47:37Having grown just a little,
0:47:37 > 0:47:40the sequoias once again shut down for winter.
0:47:44 > 0:47:49Well-fed bears are now fast asleep, tucked up in their dens.
0:47:53 > 0:47:59With thick new coats, a few hardy souls meet the cold head-on.
0:48:03 > 0:48:08For hunters, the return of the winter means new opportunities.
0:48:13 > 0:48:18The mountains are littered with reminders of fortunes won and lost.
0:48:24 > 0:48:29It takes a special breed to carve out a life on this wild frontier...
0:48:31 > 0:48:35..and survive everything the seasons throw at them.
0:48:43 > 0:48:46They embody the spirit of the high country...
0:48:50 > 0:48:55..where the west is still truly wild.
0:49:15 > 0:49:19Nothing says wild west quite like a cattle drive.
0:49:19 > 0:49:23So we join the cowboys of Three Bar Ranch on their annual drive to the
0:49:23 > 0:49:26summer pastures in the High Sierra.
0:49:34 > 0:49:37Ranch boss Diane Bohna loves her cattle so much
0:49:37 > 0:49:39she even sings to them.
0:49:39 > 0:49:41CATTLE LOW
0:49:41 > 0:49:43I hear ya, darlin'.
0:49:43 > 0:49:46This shoot was intended to be a welcome respite
0:49:46 > 0:49:47from the challenges of
0:49:47 > 0:49:50filming grizzly bears and extreme kayaking.
0:49:50 > 0:49:53Unfortunately, the cattle had other ideas.
0:49:53 > 0:49:55For field director Will Lawson,
0:49:55 > 0:49:59the first problem was adjusting to cowboy time.
0:49:59 > 0:50:05So it's 3:35 in the morning here at Three Bar Ranch in California.
0:50:07 > 0:50:09And this is our first morning
0:50:09 > 0:50:13learning what life is like as a cowboy.
0:50:13 > 0:50:14Quite a brutal start.
0:50:18 > 0:50:20Will and cameraman Owen Bissell
0:50:20 > 0:50:22head out to the ranch at the appointed time,
0:50:22 > 0:50:27only to find the 300 cattle seem to have disappeared into thin air.
0:50:30 > 0:50:33The couple just decided to leave an hour early.
0:50:33 > 0:50:36The cowboys are all back there, the cows are all up there.
0:50:36 > 0:50:39I think they've done this before.
0:50:42 > 0:50:45They now need to get ahead of the herd.
0:50:45 > 0:50:48Easier said than done in this rugged country.
0:50:48 > 0:50:51Their only option is to hitch a lift
0:50:51 > 0:50:54with ranch hand Bill in the support vehicle.
0:50:54 > 0:50:57Where are you guys at?
0:50:57 > 0:51:01And when they do find them again, they discover a new problem.
0:51:03 > 0:51:06Owen and his camera are something strange in the cattle's world
0:51:06 > 0:51:08and they don't like him at all.
0:51:10 > 0:51:14So funny, they really get kind of spooked by the tripod.
0:51:19 > 0:51:23Every time they get the gear out, the cattle go all camera shy.
0:51:25 > 0:51:27And this is even before they face
0:51:27 > 0:51:29the toughest challenges on the whole drive.
0:51:31 > 0:51:33Looks pretty steep.
0:51:33 > 0:51:35Yes, it is very steep.
0:51:35 > 0:51:36Chowchilla Hill,
0:51:36 > 0:51:40covered in thick brush and infested with rattlesnakes.
0:51:41 > 0:51:44One of the most challenging part is you are going along flat like this
0:51:44 > 0:51:47- and then you have to go straight up. - Right.
0:51:47 > 0:51:49To get the cowboys' perspective,
0:51:49 > 0:51:51Will wants to get cameras in and amongst the cattle.
0:51:51 > 0:51:56That would probably require Will to get on a horse.
0:51:56 > 0:51:57I am looking forward to it,
0:51:57 > 0:51:59but also slightly apprehensive at the same time.
0:51:59 > 0:52:01Oh, don't be.
0:52:03 > 0:52:06The next day, early roll call.
0:52:06 > 0:52:07Again.
0:52:09 > 0:52:13To get as many angles as possible, Will fits a mini camera on Ike,
0:52:13 > 0:52:15one of the stock dogs.
0:52:19 > 0:52:22You can definitely see what's going on. I think it'll work.
0:52:22 > 0:52:25A stallion called Nash is Will's ride for the day.
0:52:26 > 0:52:29Will feels he needs to look the part.
0:52:29 > 0:52:30It's going to be phenomenal.
0:52:30 > 0:52:32Do you think you'll stand out? I don't know.
0:52:32 > 0:52:35I don't think I'll stand out, necessarily.
0:52:35 > 0:52:38Owen races ahead to take a position on the hill.
0:52:41 > 0:52:43Maybe let's go through that band right there.
0:52:48 > 0:52:51Will is an experienced rider,
0:52:51 > 0:52:55but this isn't the English countryside.
0:52:55 > 0:52:59So, just started moving out on the cattle drive.
0:52:59 > 0:53:03My look is slightly different from everybody else's.
0:53:03 > 0:53:05Thank you, BBC Health and Safety.
0:53:08 > 0:53:10Good boy.
0:53:17 > 0:53:19There's a delay of some kind,
0:53:19 > 0:53:22but we can't get to the back to find out what it is.
0:53:22 > 0:53:25Hopefully Will hasn't fallen off his horse.
0:53:25 > 0:53:29This helmet pretty much saved my bacon, so I can't complain about it.
0:53:29 > 0:53:32He said he needed a ride, so we'll see.
0:53:32 > 0:53:34It's a delay they can ill-afford
0:53:34 > 0:53:36with the drive on such a tight schedule.
0:53:38 > 0:53:40But, as the saying goes,
0:53:40 > 0:53:43if you fall, get straight back in the saddle.
0:53:43 > 0:53:45He took one look at that hat
0:53:45 > 0:53:47and he was like, "I'm going to make sure that hat works."
0:53:47 > 0:53:51We're going to establish some ground rules right off the bat!
0:53:51 > 0:53:54As they resume the climb up the hill,
0:53:54 > 0:53:57the newest member of the film crew gets on with the job.
0:53:58 > 0:54:02Although sometimes he gets a little over enthusiastic.
0:54:07 > 0:54:11Will's fall has left him at the back of the drive away from the action.
0:54:16 > 0:54:19But up ahead, Owen is having more luck.
0:54:26 > 0:54:28At the end of a long, hot day,
0:54:28 > 0:54:32it's finally time for everyone to stop and quench their thirst.
0:54:40 > 0:54:45Except no-one told Owen and there's always one more shot to get.
0:54:46 > 0:54:48It's also time for Diane to look back
0:54:48 > 0:54:51on a day free from calamities...
0:54:51 > 0:54:53Well, almost.
0:54:53 > 0:54:57Other than the producer guy getting dumped first thing this morning...
0:54:57 > 0:55:00I mean, that was...
0:55:06 > 0:55:08I'm sorry!
0:55:17 > 0:55:19Over the next couple of days,
0:55:19 > 0:55:22the crew are run ragged as they try to keep up with the cattle.
0:55:35 > 0:55:39But the cows are still proving to be reluctant film stars.
0:55:39 > 0:55:42They really don't like the cameras.
0:55:42 > 0:55:46They seem to react better to our cars than they do to me on foot.
0:55:55 > 0:56:00Arriving at the forest finally brings some relief from the heat.
0:56:00 > 0:56:02But not from the foot slog.
0:56:02 > 0:56:04It's a 15-mile day.
0:56:04 > 0:56:07For Owen, mostly spent on the hoof.
0:56:09 > 0:56:15- Go on.- Go on, girls.- Keep going.
0:56:18 > 0:56:22And at last, Owen and the cattle are beginning to make friends.
0:56:24 > 0:56:26See that? They actually listened to me.
0:56:31 > 0:56:34After 70 hard miles,
0:56:34 > 0:56:37the drive comes to an end in the lush meadows of Quartz Mountain.
0:56:42 > 0:56:44And as far as the cows are concerned,
0:56:44 > 0:56:47Owen is now just part of the scenery.
0:56:50 > 0:56:52CATTLE LOW
0:56:56 > 0:56:57All right.
0:56:57 > 0:57:00Well, we struggled a bit more than we expected initially -
0:57:00 > 0:57:02who thought cows were so skittish?
0:57:02 > 0:57:07But after four days, they've accepted me into the herd.
0:57:07 > 0:57:11Got some nice shots, right down at the grass level with them.
0:57:11 > 0:57:14Wildlife filming is always unpredictable,
0:57:14 > 0:57:16but no-one expected this to be so tricky.
0:57:18 > 0:57:20It's been quite an experience.
0:57:21 > 0:57:23Cow drives are tough to film.
0:57:23 > 0:57:27Yes. One of the things that amazed me is how quickly they move.
0:57:27 > 0:57:30And watching the cowboys do their thing
0:57:30 > 0:57:32was pretty impressive, to say the least.
0:57:32 > 0:57:36I actually asked Diane if she thought I could make it as a cowboy.
0:57:36 > 0:57:37Yeah, what did she say?
0:57:37 > 0:57:40She didn't say anything, she just laughed - hysterically!
0:57:40 > 0:57:44DIANE LAUGHS
0:57:44 > 0:57:48I'd like to think that we are. What did they say today?
0:57:48 > 0:57:52"Will, it wasn't that you got thrown off the horse, you just got dusted.
0:57:52 > 0:57:54"Every cowboy gets dusted, Will."
0:57:56 > 0:57:58I got nailed by a horse, therefore...
0:57:58 > 0:58:01- Therefore, you're a cowboy. - I made it!
0:58:04 > 0:58:06- Bye, cows.- Bye, cows.
0:58:10 > 0:58:14Next time... Wild west reveals a strange frontier...
0:58:16 > 0:58:19..where the land and the sea unite.
0:58:23 > 0:58:26Restless shores drive life to survive in unlikely ways.
0:58:31 > 0:58:35And for those brave enough to take a chance, there are great rewards.