0:00:24 > 0:00:26My head's spinning.
0:00:26 > 0:00:31I can only walk a few metres without getting totally out of breath.
0:00:31 > 0:00:34There is no other place like this on the planet.
0:00:34 > 0:00:38This is the roof of the world - Tibet.
0:00:38 > 0:00:42And I've come here to try and solve the mystery
0:00:42 > 0:00:46of one of the most extreme incredible journeys of them all.
0:00:50 > 0:00:54All animal migrations are tough but surely none can be as tough
0:00:54 > 0:00:56as this one.
0:00:56 > 0:00:59- We might be in trouble.- Oh, look.
0:00:59 > 0:01:03- There, there, there, four. - Four geese, that's fantastic.
0:01:03 > 0:01:08One unique group of birds seem to defy the laws of nature.
0:01:08 > 0:01:14Bar-headed geese undertake a journey so tough it should kill them all.
0:01:14 > 0:01:18By attempting the same journey myself, I hope to find out just why
0:01:18 > 0:01:21they do it and how on earth they manage to pull through.
0:01:23 > 0:01:25I think they're laughing at us!
0:01:48 > 0:01:53This is the starting point for my mission, the forbidden city
0:01:53 > 0:01:54of Lhasa in Tibet.
0:01:54 > 0:01:58Not that many years ago, I could have been shot on sight for just
0:01:58 > 0:02:00being here.
0:02:00 > 0:02:04No foreigners were allowed in this exotic, isolated mountain citadel.
0:02:10 > 0:02:13Lhasa is one of the highest cities on earth.
0:02:13 > 0:02:18At 12,000 feet, you can get altitude sickness just going shopping around here.
0:02:28 > 0:02:30So where exactly are we?
0:02:30 > 0:02:32Lhasa is the capital of Tibet
0:02:32 > 0:02:36and it's buried in the heart of the Himalayas,
0:02:36 > 0:02:40surrounded by some of the world's highest mountains.
0:02:40 > 0:02:44It's home for part of the year to the extraordinary bar-headed geese.
0:02:44 > 0:02:48In summer, they live on extreme high-altitude lakes in Tibet,
0:02:48 > 0:02:53then, when the winter comes, they fly south to Nepal.
0:02:53 > 0:02:56And this is where we first caught up with them ten months ago.
0:03:04 > 0:03:06Bar-headed geese are unique.
0:03:06 > 0:03:11Their migration takes them higher than any other bird on the planet.
0:03:11 > 0:03:15Where they fly, no other animal dares go.
0:03:15 > 0:03:19To try to understand more about these exceptional animals,
0:03:19 > 0:03:23a team of American and Indian scientists have set up an ambitious
0:03:23 > 0:03:27project to follow the birds on their annual migration.
0:03:33 > 0:03:35The plan is to catch the birds at
0:03:35 > 0:03:38the most southerly end of their migration in Nepal.
0:03:41 > 0:03:45The team use the skills of the local Shikari hunters
0:03:45 > 0:03:48to set a trap for the bar-heads.
0:03:48 > 0:03:53This traditional system holds them by the legs, but won't hurt them in any way.
0:03:53 > 0:03:58Two strong healthy geese are carefully selected and fitted
0:03:58 > 0:04:02with hi-tech satellite transmitters.
0:04:05 > 0:04:08These are extremely lightweight tracking devices
0:04:08 > 0:04:11and won't impede the birds' movement,
0:04:11 > 0:04:15but they will allow us and the scientists to follow their every move.
0:04:21 > 0:04:25Our birds are named after the mountaineers who first climbed Mount Everest.
0:04:25 > 0:04:29So the first goose is called Tenzing.
0:04:32 > 0:04:37Another tracker is attached to the second goose, called Hillary.
0:04:40 > 0:04:44The power units on the trackers should last for the next ten months,
0:04:44 > 0:04:50- time enough to record their entire round trip all the way to Tibet and back.- Good to go!
0:04:58 > 0:05:03Immediately, the satellite trackers start to transmit the birds' position,
0:05:03 > 0:05:05telling us exactly where they are.
0:05:09 > 0:05:14A few weeks later in mid-March, their journey begins.
0:05:14 > 0:05:18Hillary and Tenzing turned north and flew towards Tibet.
0:05:22 > 0:05:27Would the trackers survive the extreme altitude and cold?
0:05:27 > 0:05:31For that matter, would Hillary and Tenzing?
0:05:31 > 0:05:34In fact, the data we got was awesome.
0:05:34 > 0:05:38We were treated to an hour-by-hour signal as they flew right over
0:05:38 > 0:05:39the top of the Himalayas.
0:05:45 > 0:05:51Hillary and Tenzing flew up to 6,000 metres, that's nearly 20,000 feet,
0:05:51 > 0:05:54and hit speeds of over 50mph.
0:05:54 > 0:05:58Both of our birds then landed on the extreme high-altitude lakes
0:05:58 > 0:06:00and settled down for the summer.
0:06:03 > 0:06:06So what's it like in the goose's world?
0:06:06 > 0:06:09How do they survive at these extreme altitudes?
0:06:09 > 0:06:13And why do they undertake such a death-defying journey?
0:06:13 > 0:06:17To answer these questions, I'm going to try and join them
0:06:17 > 0:06:19in their summer home in Tibet
0:06:19 > 0:06:24and then make the return journey with them back across the Himalayas.
0:06:26 > 0:06:28I'm getting my gear sorted.
0:06:28 > 0:06:30Screws.
0:06:30 > 0:06:32If it all goes according to plan,
0:06:32 > 0:06:36we're going to end up nearly 20,000 feet up a mountain
0:06:36 > 0:06:39for an inflight rendezvous with Hillary and Tenzing.
0:06:43 > 0:06:45Up where we're going to be climbing
0:06:45 > 0:06:48there's a real danger of altitude sickness.
0:06:48 > 0:06:52Fluid leaks into your lungs, or, even worse, leaks into your brain.
0:06:52 > 0:06:54It's potentially fatal.
0:07:00 > 0:07:04Somehow the geese can handle the problems of high altitude
0:07:04 > 0:07:07but it's totally different for us humans.
0:07:07 > 0:07:10I can't just go to where the birds are right away.
0:07:10 > 0:07:13Because if I did, I'd almost certainly die.
0:07:13 > 0:07:17I've got to give my body a chance to adapt to this extreme altitude
0:07:17 > 0:07:19and that takes time.
0:07:19 > 0:07:25So, to begin with, I have to stay in Lhasa to start to acclimatise.
0:07:37 > 0:07:40Lhasa actually means "home of the gods".
0:07:47 > 0:07:51This place is the focus for pilgrims from all over Tibet.
0:08:18 > 0:08:21People will spend literally all day
0:08:21 > 0:08:23prostrating themselves in front of the temple.
0:08:23 > 0:08:28The flagstones are polished smooth by centuries of pilgrims.
0:08:48 > 0:08:50Well, it's time to say goodbye to Lhasa.
0:08:50 > 0:08:54We've had three days here and we're all feeling quite good now.
0:08:54 > 0:08:58So the altitude is having less of an effect, so it's time to go higher.
0:08:58 > 0:09:03And every time we feel good, we just keep adding another thousand feet a day.
0:09:03 > 0:09:08So from now on it's going to be a little less luxurious,
0:09:08 > 0:09:11our accommodation, we're going to be camping, so we need to buy food.
0:09:13 > 0:09:16Sorry!
0:09:16 > 0:09:18Look. Say hello!
0:09:22 > 0:09:24I'm going to definitely miss...
0:09:26 > 0:09:30I'm gonna miss this place. What we're doing here now at the moment
0:09:30 > 0:09:35is just stocking up on provisions and this is a vegetarian's dream, as you can imagine,
0:09:35 > 0:09:39and hoping that by the time we reach the birds, which is in a few days' time,
0:09:39 > 0:09:40that they will still be there.
0:09:40 > 0:09:45Thankfully, they haven't moved at the moment, but they could go at any moment.
0:09:45 > 0:09:49So...time to push on, I suppose.
0:10:01 > 0:10:03Well, we're on our way.
0:10:03 > 0:10:05Wherever we are, the team of scientists
0:10:05 > 0:10:08will regularly update us via a satellite phone
0:10:08 > 0:10:10to tell us exactly where the geese are.
0:10:14 > 0:10:17From the latest update, we know Hillary is pretty much
0:10:17 > 0:10:20out of range for us just now.
0:10:20 > 0:10:23So we've decided to try and meet up with Tenzing.
0:10:28 > 0:10:30But the lake he's on
0:10:30 > 0:10:36is well over 15,000 feet high and it's the other side of a very high pass.
0:10:42 > 0:10:45But why is Tenzing up here?
0:10:45 > 0:10:50Well, high-altitude lakes make for a perfect nesting site.
0:10:50 > 0:10:54Bar-headed geese are able to survive the altitude and the cold,
0:10:54 > 0:10:59but very few other animals can, and that includes predators.
0:10:59 > 0:11:02It's just far too extreme.
0:11:10 > 0:11:14The lakes are simply too high and too difficult for predators
0:11:14 > 0:11:20to get to, so this is a great place for the geese to nest and hatch out
0:11:20 > 0:11:22the next generation of bar-heads.
0:11:35 > 0:11:39During the short summer, there is an explosion of plant growth.
0:11:41 > 0:11:45So, actually, there's loads for the geese and their new families to eat.
0:11:53 > 0:11:55If we can get up to Tenzing
0:11:55 > 0:11:59we will probably find a big goose-nesting site.
0:11:59 > 0:12:01We may even find Tenzing is a proud father
0:12:01 > 0:12:04and has his own little family up here.
0:12:05 > 0:12:08If we can get there.
0:12:16 > 0:12:21To help avoid altitude sickness, we shouldn't climb more than
0:12:21 > 0:12:24300 metres per day.
0:12:24 > 0:12:25The problem is
0:12:25 > 0:12:29finding somewhere to stay overnight which is at the right height.
0:12:31 > 0:12:33We've decided to come down to...
0:12:33 > 0:12:35Well...
0:12:35 > 0:12:41there are several words I can use for it, none of them broadcastable.
0:12:41 > 0:12:45So we're just trying to find some accommodation somewhere.
0:12:45 > 0:12:51The organisation side of things isn't panning out to be just as we'd like,
0:12:51 > 0:12:54but after tonight we're going to be camping so we'll be
0:12:54 > 0:12:56in charge of our own destinies.
0:12:56 > 0:12:58We'll be cold,
0:12:58 > 0:13:01but we'll be in charge of our own destinies.
0:13:01 > 0:13:05How are you describing this accommodation?
0:13:05 > 0:13:07It's completely squalid.
0:13:07 > 0:13:11You'd catch something. Four people to a room, blankets covered in stains,
0:13:11 > 0:13:13filth all over the floor.
0:13:13 > 0:13:17I really don't think we can stay here, but where can we stay?
0:13:17 > 0:13:19I'm mad keen, it sounds perfect!
0:13:23 > 0:13:27So, after a good night's sleep, it's time for a bit of breakfast
0:13:27 > 0:13:29in the local greasy spoon.
0:13:37 > 0:13:39The local roadside butcher
0:13:39 > 0:13:42has just slaughtered himself a couple of yaks
0:13:44 > 0:13:48and everyone's come round to check out the best cuts.
0:13:50 > 0:13:52All nice and fresh and steaming.
0:13:55 > 0:13:58Just what you want to see on a full stomach.
0:14:01 > 0:14:02But we don't mind the look of this.
0:14:02 > 0:14:06The thing we're most worried about is the weather.
0:14:08 > 0:14:12It's sunny enough in the village but winter is just around the corner
0:14:12 > 0:14:16and there are ominous clouds over the surrounding mountains.
0:14:17 > 0:14:21These snow clouds look pretty thick and if we get too much snow,
0:14:21 > 0:14:26it will make crossing the high pass to Tenzing very difficult.
0:14:26 > 0:14:27Even impossible.
0:14:32 > 0:14:36We're just filling up the cars because this is going to be the last
0:14:36 > 0:14:40sort of town that we're going to be in for a while,
0:14:40 > 0:14:44because we're going to head up to the pass which is over 5,000 metres.
0:14:44 > 0:14:50So we're talking probably 16,000, 17,000 feet.
0:14:50 > 0:14:53We don't know how we're going to be able to cope with that,
0:14:53 > 0:14:59but on the other side of that pass is the lake that Tenzing, our male bird, is sat,
0:14:59 > 0:15:01and has been for a while, so...
0:15:04 > 0:15:06It's snowing now.
0:15:06 > 0:15:08That's going to be a problem, I think.
0:15:19 > 0:15:21Well, we've decided to have a crack at the pass
0:15:21 > 0:15:24even though everybody else has turned round.
0:15:24 > 0:15:28We have got a big truck with all our gear in it and that's going to try
0:15:28 > 0:15:32and break through the trail for us and try and bash through the snow.
0:15:32 > 0:15:34We don't know if we'll make it to the other side
0:15:34 > 0:15:39but Tenzing is on the other side waiting at a lake for us.
0:15:39 > 0:15:42This weather might mean that he decides to head south.
0:15:42 > 0:15:46So this might be our only shot.
0:15:46 > 0:15:47We'll see how it goes.
0:15:47 > 0:15:51It's looking all right at the moment.
0:15:52 > 0:15:57Although we're desperate not to miss Tenzing, we have to be very careful,
0:15:57 > 0:15:59this is no place for taking risks.
0:15:59 > 0:16:02If we get into trouble, we're on our own.
0:16:07 > 0:16:10- No. No.- No? Not possible, no?- No, no.
0:16:10 > 0:16:15- OK.- He's getting out.
0:16:17 > 0:16:19He doesn't think it's possible.
0:16:19 > 0:16:21I don't know what he thinks.
0:16:21 > 0:16:24- They're going up.- We should go on.
0:16:24 > 0:16:25- We should go on?- I think.
0:16:25 > 0:16:27- This is nothing so far.- Ah-ha.
0:16:33 > 0:16:35We're about,
0:16:35 > 0:16:39between 4,000 and 5,000 metres,
0:16:39 > 0:16:41and our guide is
0:16:41 > 0:16:44running up the hill.
0:16:44 > 0:16:47Needless to say, I'm ambling.
0:16:47 > 0:16:51Running is beyond me at the moment.
0:16:51 > 0:16:53If I tried to run up here,
0:16:53 > 0:16:55I would
0:16:55 > 0:16:57pass out, I think.
0:17:06 > 0:17:08- Fall down also.- Slightly concerned.
0:17:08 > 0:17:10We'll find out what's going on.
0:17:12 > 0:17:14Oh, it's a snow plough.
0:17:16 > 0:17:18That's why the roads aren't clear,
0:17:18 > 0:17:21because the snow plough is stuck off the road.
0:17:21 > 0:17:24It's fallen down the ravine.
0:17:24 > 0:17:25That does not bode well.
0:17:27 > 0:17:31I think we should possibly think about a retreat.
0:17:34 > 0:17:39I'm not looking forward to the trip down.
0:17:39 > 0:17:41We might be in trouble.
0:17:43 > 0:17:48It's odd to think I can hardly walk up here without getting exhausted,
0:17:48 > 0:17:54but the geese are warming up for a thousand-mile flight over the highest barrier on earth.
0:17:54 > 0:17:58They're fuelled up, they're super-fit and they're ready to go.
0:18:01 > 0:18:04We need to get up to the lake as fast as possible.
0:18:08 > 0:18:11This pass is rapidly turning into
0:18:11 > 0:18:14our...
0:18:14 > 0:18:16Nemesis...
0:18:16 > 0:18:17and now...
0:18:17 > 0:18:20- the truck is stuck.- It's stuck.
0:18:20 > 0:18:23He can't get up there, the tyres are very bald.
0:18:23 > 0:18:25So now he has to reverse back down
0:18:25 > 0:18:28and we'll camp and we'll wait till tomorrow morning
0:18:28 > 0:18:32and hope this freezes solid and then we can get over the pass, hopefully.
0:18:32 > 0:18:34Sounds like a plan.
0:18:37 > 0:18:43We've no choice but to camp beside the road and the temperature is starting to plummet.
0:18:43 > 0:18:46That was a good...
0:18:46 > 0:18:48night in the tent.
0:18:48 > 0:18:50It could have been a lot colder.
0:18:50 > 0:18:53Outside it was minus eight,
0:18:53 > 0:18:57but inside the tents it was measured at minus two, so shows what a little
0:18:57 > 0:19:00bit of insulation will do for you.
0:19:00 > 0:19:03The best stuff, the absolute best stuff in the cold,
0:19:03 > 0:19:05is what's inside this jacket.
0:19:05 > 0:19:08And I hate to say it but it is goose down.
0:19:08 > 0:19:10So my apologies to Hillary and Tenzing,
0:19:10 > 0:19:15but it is amazingly warm for the thickness.
0:19:15 > 0:19:20It's only a matter of a centimetre thick, or even thinner than that,
0:19:20 > 0:19:22and it's absolute toast.
0:19:22 > 0:19:25And of course that's the secret of how the geese
0:19:25 > 0:19:27survive the extreme cold up here.
0:19:27 > 0:19:31They've got their own superb down jackets to keep them warm.
0:19:42 > 0:19:43There.
0:19:43 > 0:19:46No, no, no.
0:19:46 > 0:19:48We can hear geese.
0:19:50 > 0:19:52We can't see them, but we can hear them.
0:19:52 > 0:19:53But it's clearing,
0:19:53 > 0:19:55we might get a glimpse of them.
0:19:59 > 0:20:01That's great.
0:20:01 > 0:20:03Maybe Tenzing
0:20:03 > 0:20:07is actually making his way over the pass as we've struggled
0:20:07 > 0:20:08and decided to stop.
0:20:10 > 0:20:12It's much easier to fly.
0:20:14 > 0:20:16This is promising.
0:20:16 > 0:20:20There are definitely geese nearby and the weather's cleared,
0:20:20 > 0:20:23but the temperature's still falling.
0:20:25 > 0:20:29The increasing cold could make the lake freeze over,
0:20:29 > 0:20:33then there'll be no food for Tenzing and that will trigger his journey
0:20:33 > 0:20:35back south where it's warmer.
0:20:35 > 0:20:40We know from the latest data he's still on the lake this morning,
0:20:40 > 0:20:42but he could go at any time.
0:20:42 > 0:20:45The pressure's on.
0:20:45 > 0:20:48But our plan's working -
0:20:48 > 0:20:52the roads froze hard in the night and we've got grip.
0:20:56 > 0:20:58He's not going to move.
0:20:58 > 0:21:00CAR HORN BEEPS
0:21:00 > 0:21:03Now you don't see them getting stuck.
0:21:03 > 0:21:05That's proper all-wheel drive.
0:21:09 > 0:21:11What are they doing up here?
0:21:16 > 0:21:20This is an avalanche that we're driving through.
0:21:20 > 0:21:25I don't know who's cut the path, but it's just come down from this slope here.
0:21:25 > 0:21:30There's quite a lot of snow come down, you can see it's a couple of metres thick here.
0:21:30 > 0:21:33I can't believe this, this is crazy.
0:21:33 > 0:21:38If that could go now, we could have avalanches coming down off the road right on top of us.
0:21:40 > 0:21:42It's pretty extreme stuff.
0:21:47 > 0:21:51Thankfully, our drivers are very brave men and very competent drivers,
0:21:51 > 0:21:55and they've decided to push on through and we're getting
0:21:55 > 0:21:59close to the top of the pass now, so who knows what we're going to see.
0:21:59 > 0:22:01It looks like we're going to make it.
0:22:19 > 0:22:20Absolutely stunning.
0:22:31 > 0:22:32We've done it.
0:22:34 > 0:22:38We got to the top of the pass.
0:22:38 > 0:22:40The cars have come as far as they can.
0:22:43 > 0:22:46What we hoped to do
0:22:46 > 0:22:51is to get down there and see the shore,
0:22:51 > 0:22:53but there's no way we can risk
0:22:53 > 0:22:58travelling down this steep pass, the far side, and not being able
0:22:58 > 0:23:02to get back up again, back to where our truck is with all our supplies.
0:23:06 > 0:23:09But that's what we came to see.
0:23:09 > 0:23:14There it is. That's Tenzing's lake, where he's been all summer.
0:23:20 > 0:23:23But this is as close as we're going to get.
0:23:30 > 0:23:32Well, needless to say, this is
0:23:32 > 0:23:34one hell of a refuge for him
0:23:36 > 0:23:38and all the other geese.
0:23:40 > 0:23:42It's high,
0:23:42 > 0:23:44it's away from many, many predators.
0:23:54 > 0:23:56I'm so happy.
0:23:56 > 0:23:58What an experience.
0:23:58 > 0:23:59What a place.
0:24:04 > 0:24:05Oh, look!
0:24:05 > 0:24:07There, there, there. There's four.
0:24:07 > 0:24:10There, we have. We've definitely got geese.
0:24:12 > 0:24:16- Four geese. - High up there, do you see them?
0:24:16 > 0:24:18There are four of them in a clump there.
0:24:20 > 0:24:22Four geese, that's fantastic.
0:24:22 > 0:24:27We're at 5,200 metres
0:24:27 > 0:24:30and they're battling into a head wind,
0:24:30 > 0:24:36at least a couple of hundred feet, 200, 300, maybe more, feet above us.
0:24:38 > 0:24:40This is maybe why Tenzing hasn't left.
0:24:42 > 0:24:43They can fly at 50mph,
0:24:43 > 0:24:47but this head wind must be making life so difficult for them.
0:24:47 > 0:24:50They're hardly making any progress.
0:24:52 > 0:24:55No, they're turning back, they're turning back.
0:24:55 > 0:24:58Maybe this is why they haven't left.
0:25:00 > 0:25:03God, and we thought life was tough for us,
0:25:05 > 0:25:07but flying into a head wind
0:25:07 > 0:25:10at this altitude, at this temperature,
0:25:10 > 0:25:14well, just talking about it's knackering for me.
0:25:21 > 0:25:27Being up here has really brought home what the geese are up against.
0:25:27 > 0:25:29It's not just the altitude.
0:25:29 > 0:25:32Up here in the mountains, there's some really extreme weather.
0:25:34 > 0:25:38They may have to contend with winds of 100mph or more.
0:25:56 > 0:26:00If they go for it and they hit the wrong winds, they could be blown
0:26:00 > 0:26:06backwards, trapped on a mountain top or knocked clean out of the sky.
0:26:06 > 0:26:09The timing has to be perfect.
0:26:14 > 0:26:16Tenzing has moved.
0:26:16 > 0:26:20Whilst we were struggling back down the mountain to camp,
0:26:20 > 0:26:23it looks like his journey has actually begun.
0:26:23 > 0:26:25The conditions are getting so harsh,
0:26:25 > 0:26:27the geese have started to head south.
0:26:29 > 0:26:31But he's stopped again.
0:26:31 > 0:26:33So, we're off after him.
0:26:38 > 0:26:42I want to follow him right over the Himalayas, if I possibly can.
0:26:52 > 0:26:55But this still involves pit stops as we go.
0:26:55 > 0:26:58We've got to keep up with our acclimatisation.
0:27:01 > 0:27:02I know we keep banging on about
0:27:02 > 0:27:05acclimatisation and getting acclimatised,
0:27:05 > 0:27:10and I feel I should explain a little bit about what that's about,
0:27:10 > 0:27:12because, you know, our geese are
0:27:12 > 0:27:17superbly designed to actually live up at this altitude and we're not.
0:27:17 > 0:27:20But human bodies and mammal bodies in general
0:27:20 > 0:27:24have an amazing capacity to adapt, given the time.
0:27:24 > 0:27:27We've only been here now a week, or a bit longer than that,
0:27:27 > 0:27:29and we're still in the early stages.
0:27:29 > 0:27:33The body is saying, "Hang on, there's not much oxygen here,
0:27:33 > 0:27:35"let's concentrate the blood."
0:27:35 > 0:27:39Now, to make red blood cells, that takes about two weeks
0:27:39 > 0:27:41before that really starts to kick in
0:27:41 > 0:27:44and we start to get more red blood cells to carry the oxygen.
0:27:44 > 0:27:49What I'm at the stage at the moment, just in this first week, is actually
0:27:49 > 0:27:51just peeing a lot.
0:27:51 > 0:27:55That doesn't sound like a very clever thing for the body to do, but what that's doing
0:27:55 > 0:27:59is actually removing the fluid part of the blood and therefore
0:27:59 > 0:28:03upping the cells part, the red blood cells that carry the oxygen.
0:28:03 > 0:28:06So just by reducing the fluid in the blood,
0:28:06 > 0:28:09you're already sort of increasing the percentage of
0:28:09 > 0:28:12red blood cells, so that's why I have to keep taking a leak.
0:28:19 > 0:28:23We're on our way to Xigaze, Tibet's second biggest city
0:28:23 > 0:28:28and right on our path as we try to follow Tenzing's route.
0:28:28 > 0:28:31And I'm bound to say it's going to be very pleasant
0:28:31 > 0:28:32to stop camping for a night.
0:28:42 > 0:28:43It is odd to look out over what
0:28:43 > 0:28:46looks like a normal town, but realise this is all actually
0:28:46 > 0:28:51three times higher than Britain's highest mountain.
0:29:03 > 0:29:07So far we've been concentrating on Tenzing because he's the only one
0:29:07 > 0:29:09we could hope to get near.
0:29:11 > 0:29:14But in Xigaze, there's been some news.
0:29:18 > 0:29:20We have been hearing from Hillary
0:29:20 > 0:29:24right up till yesterday and then suddenly nothing.
0:29:24 > 0:29:26This could be down to three reasons.
0:29:26 > 0:29:29Her transmitter could have failed, which is unlikely.
0:29:29 > 0:29:31Bad weather could be affecting the reception.
0:29:31 > 0:29:35But there's a third, much more exciting, possibility.
0:29:35 > 0:29:37When she's in the air, when she's actually flying,
0:29:37 > 0:29:39the transmitter won't work very well.
0:29:39 > 0:29:41Now this could mean that
0:29:41 > 0:29:45both our geese, Tenzing and Hillary, are actually on the move.
0:29:45 > 0:29:49We're coming to the hardest part of our mission for the geese and us.
0:29:49 > 0:29:52Next stop, base camp.
0:30:00 > 0:30:02Actually, not Everest base camp.
0:30:02 > 0:30:06We're heading for a different mountain, but along our route
0:30:06 > 0:30:09there's an unmistakeable landmark.
0:30:12 > 0:30:15That there is the biggest mountain in the world.
0:30:15 > 0:30:19Yep, that is Everest.
0:30:19 > 0:30:24It's an interesting thought that this range that our bar-headed geese have to fly over
0:30:24 > 0:30:26is still a young range.
0:30:26 > 0:30:29It's not particularly old and it's still growing,
0:30:29 > 0:30:33and the important thing about that is that it might hold some clue as to why
0:30:33 > 0:30:39bar-headed geese fly over this range, rather than round it like a lot of other birds.
0:30:39 > 0:30:41It's an interesting theory.
0:30:43 > 0:30:47Around 70 million years ago, India crashed into Asia,
0:30:47 > 0:30:53and, as a result of this epic collision, the Himalayas rose up.
0:30:53 > 0:30:56But this all happened in a number of stages bit by bit,
0:30:56 > 0:31:02and it's just possible the ancestors of bar-headed geese were already making this trip
0:31:02 > 0:31:06well before the mountains became so exceptionally high.
0:31:07 > 0:31:10As the Himalayas continued to rise,
0:31:10 > 0:31:15the geese just raised their game with them and flew higher and higher
0:31:15 > 0:31:18until they moved up into a different zone.
0:31:23 > 0:31:26Where we are now, there is half the amount of oxygen
0:31:26 > 0:31:28that there is at sea level.
0:31:28 > 0:31:33It makes doing anything physical desperately hard work.
0:31:33 > 0:31:35You've got to remember we're at 17,000 feet,
0:31:35 > 0:31:37so there's not a great deal of oxygen.
0:31:37 > 0:31:40That's why we've got to take it in turns to do the digging -
0:31:40 > 0:31:42I'm at the back of the queue!
0:31:51 > 0:31:55That's it, I'm just starting to feel
0:31:55 > 0:31:58slightly dizzy now.
0:31:58 > 0:32:02I've been going about two minutes
0:32:02 > 0:32:08and yet all I'm doing is just lightly tossing this snow
0:32:08 > 0:32:11and it's, er,
0:32:11 > 0:32:12it's knackering.
0:32:18 > 0:32:24This mountain is Shishmapangma, an 8,000-metre peak.
0:32:24 > 0:32:27The data shows that both Hillary and Tenzing
0:32:27 > 0:32:32crossed just to one side on their northward journey up to Tibet.
0:32:32 > 0:32:34If our calculations are right,
0:32:34 > 0:32:39it's most likely they will fly back south this way using the same route.
0:32:41 > 0:32:45If we can get up high enough to the goose fly-by zone, we might
0:32:45 > 0:32:52just be there when they go by, but we've still got another 1,000 metres to go.
0:32:52 > 0:32:56This will be the toughest part of the journey for us
0:32:56 > 0:32:57and Hillary and Tenzing.
0:33:07 > 0:33:10No other bird on earth regularly flies this high.
0:33:10 > 0:33:15Where they go, there is less than one third the amount of oxygen
0:33:15 > 0:33:19that there is at sea level and it can be minus 50 degrees.
0:33:21 > 0:33:28The geese can fly up to 50mph but add on a possible tailwind of up to 100mph
0:33:28 > 0:33:33and they can slingshot over the roof of the world in a matter of hours.
0:33:33 > 0:33:37This whole migration can be over in a single day.
0:34:10 > 0:34:13But, then again, the conditions have to be perfect
0:34:13 > 0:34:17and they can change at the drop of a hat.
0:34:58 > 0:35:03It got to, I think, minus 19, I think, last night.
0:35:03 > 0:35:05I just want to get up,
0:35:05 > 0:35:08do that final push, get up over...
0:35:08 > 0:35:12these mountains and down the other side and down into lower altitude,
0:35:12 > 0:35:16where I'm going to feel so much better.
0:35:16 > 0:35:19I don't know, maybe the geese feel that way as well,
0:35:19 > 0:35:21the ones that have done it before.
0:35:21 > 0:35:25The kiddies of this season might not know what's going to hit them,
0:35:25 > 0:35:29but the adults certainly will, and maybe that's why they're delaying,
0:35:29 > 0:35:31because they feel as crap as I do.
0:35:31 > 0:35:35My problem is I can't get enough oxygen out of the air up here.
0:35:35 > 0:35:38My body is really struggling,
0:35:38 > 0:35:41but how on earth do the geese actually manage to do it?
0:35:44 > 0:35:48Well, the answer is, they're mutants.
0:35:48 > 0:35:53Way back in their evolution, something amazing happened.
0:35:53 > 0:35:55Bar-heads developed a mutation
0:35:55 > 0:35:58that altered the chemical composition of their blood.
0:35:58 > 0:36:02This mutation allowed their blood to extract far more oxygen from every breath,
0:36:02 > 0:36:09which enabled the bar-headed geese to cope with the effects of altitude with no troubles at all.
0:36:10 > 0:36:12Unlike me.
0:36:17 > 0:36:21There's now no way we are physically capable of carrying our gear ourselves
0:36:23 > 0:36:28and it's the end of the road for the vehicles. So it's over to yak power.
0:36:36 > 0:36:39Like geese, yaks are highly specialised
0:36:39 > 0:36:41to live up at these heights.
0:36:41 > 0:36:45I wish I could say the same for me because, despite our careful calculations,
0:36:48 > 0:36:52I'm starting to worry altitude sickness may have got me in its grip.
0:36:52 > 0:36:53I'm feeling grim.
0:36:55 > 0:36:58I get migraines quite commonly
0:36:58 > 0:37:01and I've had...
0:37:01 > 0:37:03a migraine now
0:37:03 > 0:37:05for about three days.
0:37:05 > 0:37:07Now, the problem with that is,
0:37:07 > 0:37:10there's another thing that happens at altitude, which is
0:37:10 > 0:37:15your brain swells, you get what they call cerebral oedema,
0:37:15 > 0:37:19and if that's what I've got, and it's not a migraine, then that
0:37:19 > 0:37:22can be very, very serious, so I think the option
0:37:22 > 0:37:25to take really is to get
0:37:25 > 0:37:27to lower altitude as soon as possible
0:37:27 > 0:37:29because...
0:37:31 > 0:37:34I can't go on feeling like this.
0:37:37 > 0:37:43Despite desperately wanting to carry on and being tantalisingly close to our goal,
0:37:43 > 0:37:47it's clear to everyone that this is the end of the line for me.
0:37:47 > 0:37:49The problem is I can't tell whether
0:37:49 > 0:37:53- it's a migraine or not, and that's...- We can't take any chances at all.
0:37:53 > 0:37:56- It's just been going on too long now.- Yes.
0:38:26 > 0:38:29Obviously things haven't turned out the way that we hoped,
0:38:29 > 0:38:35but Steve has been getting worse and worse over the past three days and we just can't take any chances.
0:38:35 > 0:38:38Which is a shame because today was going to be our big push.
0:38:38 > 0:38:41We were going to try and get as high as we possibly could,
0:38:41 > 0:38:44maybe even up to goose fly-by level,
0:38:44 > 0:38:47and we had everything we needed.
0:38:47 > 0:38:50We've got the yaks, we've got fantastic weather
0:38:50 > 0:38:56and we spent 14 days acclimatising, trying to getting our bodies ready to get up there,
0:38:56 > 0:38:59but it seems our bodies just can't take it.
0:38:59 > 0:39:03Altitude sickness is a potential killer
0:39:03 > 0:39:06and the only sure way to reduce the symptoms
0:39:06 > 0:39:09is to get down to lower altitude just as fast as possible.
0:39:09 > 0:39:12We've failed.
0:40:29 > 0:40:36It's only when you stop feeling bad that you realise just how bad you did feel.
0:40:37 > 0:40:41And now I'm down at much lower altitude,
0:40:41 > 0:40:46the nausea has gone, the headache's gone,
0:40:46 > 0:40:47I'm warm again,
0:40:49 > 0:40:52but I miss being up there.
0:40:52 > 0:40:58It was such a strange and stunning place.
0:41:01 > 0:41:05It might be the last time I get to that sort of altitude
0:41:05 > 0:41:11and there really is no other place on earth like it, really.
0:41:11 > 0:41:14You just look around and you see all these peaks and you just want
0:41:14 > 0:41:18to go to the top of them and I can understand why people do that now.
0:41:20 > 0:41:23And I can understand why people die up there as well,
0:41:23 > 0:41:26just refusing to accept that
0:41:26 > 0:41:28they shouldn't be there.
0:41:45 > 0:41:48Next stop, Nepal.
0:41:50 > 0:41:53Thank you very, very much.
0:41:53 > 0:41:55Oh, here we go, it's tied as well.
0:42:04 > 0:42:06- Thank you.- Thank you very much. Bye.
0:42:06 > 0:42:07Bye-bye. Bye!
0:42:16 > 0:42:20It's so strange, this whole trip has been about the hardship of
0:42:20 > 0:42:22getting out of Tibet and getting over those mountains
0:42:22 > 0:42:26and dealing with the altitude, that I haven't thought about Nepal,
0:42:26 > 0:42:28where we're going or where the geese are going.
0:42:28 > 0:42:31And now it's happening and I have no idea what to expect.
0:42:31 > 0:42:36I've never been there before but I'm really looking forward to it.
0:42:37 > 0:42:41We're heading for Nepal because that's where the geese were tagged
0:42:41 > 0:42:46and that's where they'll finish their journey if and when they cross the mountains.
0:42:48 > 0:42:51But it's starting to get just a bit late.
0:42:54 > 0:42:56As I'm crossing the border,
0:42:56 > 0:43:01Hillary and Tenzing are still in Tibet up on the high-altitude lakes.
0:43:01 > 0:43:08The geese are massing together in groups close to the mountains, waiting, but waiting for what?
0:43:10 > 0:43:14The geese know by the change in day length that it's time to go.
0:43:14 > 0:43:17Perhaps they're waiting for exactly the right weather.
0:43:20 > 0:43:23Right now they seem to be stuffing their faces,
0:43:23 > 0:43:25getting as much fuel on board as they possibly can.
0:43:25 > 0:43:29This one flight will burn a huge amount of energy.
0:43:30 > 0:43:35And talking about energy, we may have a problem.
0:43:35 > 0:43:40The power supplies on the satellite transmitters Hillary and Tenzing are carrying
0:43:40 > 0:43:44are only supposed to last ten months and that time is more or less up.
0:43:48 > 0:43:51All I can do now is try and get ahead of them and wait for them
0:43:51 > 0:43:54at their final destination in Nepal.
0:44:05 > 0:44:07Hello!
0:44:07 > 0:44:09HORN BEEPS
0:44:19 > 0:44:22Well, they're still behind those mountains.
0:44:22 > 0:44:28It seems that Hillary and Tenzing haven't found the motivation to fly all the way over here yet.
0:44:28 > 0:44:31And, standing here, we can only guess why that isn't so.
0:44:31 > 0:44:34It could be the extreme cold on the other side,
0:44:34 > 0:44:36it could be that they're waiting for the right winds,
0:44:36 > 0:44:39or it could be something more sinister.
0:44:39 > 0:44:42You see, they might not come over here at all.
0:44:42 > 0:44:48Flying over the Himalayas isn't the only problem they have to face.
0:44:48 > 0:44:51On top of bad weather and transmitter problems,
0:44:51 > 0:44:53there's now something else to worry about.
0:44:53 > 0:44:56Something that's been making headline news.
0:44:56 > 0:45:00China has become the latest Asian country to confirm an outbreak of
0:45:00 > 0:45:04bird flu. Today, China confirmed two new outbreaks of the virus.
0:45:04 > 0:45:09Earlier this year, the flu virus killed 6,000 wild geese and ducks
0:45:09 > 0:45:11in China's Qinghai Lake.
0:45:11 > 0:45:15That's worrying because it's a staging post for migratory birds.
0:45:17 > 0:45:21Millions of years of evolution have prepared Hillary and Tenzing
0:45:21 > 0:45:24for flying over the highest mountains in the world,
0:45:24 > 0:45:27but nothing could possibly have prepared them for the bird flu.
0:45:29 > 0:45:32It looks like thousands of geese have already died
0:45:32 > 0:45:34and if our birds are on lakes with
0:45:34 > 0:45:38infected birds, this journey could come to an abrupt halt.
0:45:43 > 0:45:46But we have to remain hopeful.
0:45:46 > 0:45:48We know from the latest data,
0:45:48 > 0:45:51the geese are still moving around on the other side.
0:45:51 > 0:45:55So I'm rushing towards Royal Chitwan National Park,
0:45:55 > 0:45:59the very same place Hillary and Tenzing were tagged nearly a year ago,
0:45:59 > 0:46:01to wait for them to arrive.
0:46:01 > 0:46:05It's amazing that their tiny little transmitters are still
0:46:05 > 0:46:10kicking out a signal but, worryingly, it looks like Hillary's battery
0:46:10 > 0:46:11is starting to fade.
0:46:15 > 0:46:18Royal Chitwan is an amazing place,
0:46:18 > 0:46:23absolutely teeming with spectacular wildlife.
0:46:23 > 0:46:26It's famous for its wild Indian rhinoceros.
0:46:28 > 0:46:31And it's famous for its tigers.
0:46:35 > 0:46:38But what's the attraction for bar-headed geese?
0:46:41 > 0:46:45Well, during the winter, this place is fantastically lush.
0:46:45 > 0:46:49There's just no comparison with the high-altitude lakes in Tibet.
0:46:49 > 0:46:53There's tons of food for hungry geese.
0:46:53 > 0:46:57So you might think this would be paradise for Hillary and Tenzing?
0:46:57 > 0:46:58Well, not really.
0:46:58 > 0:47:01Royal Chitwan has a dark side.
0:47:04 > 0:47:08Dhan Badur has worked here all his life.
0:47:08 > 0:47:11So this is obviously quite an excellent place for the birds to live,
0:47:11 > 0:47:14but quite dangerous as well, I suppose?
0:47:14 > 0:47:15Yes, it is, yes.
0:47:15 > 0:47:20You have to be very careful when you walk through the bushes. Anything could happen.
0:47:23 > 0:47:28- This is a very good area for the tigers and the rhino.- OK.
0:47:28 > 0:47:29- OK?- Right.
0:47:37 > 0:47:39Steve, look, the tiger tracks.
0:47:41 > 0:47:43Thanks. Is that a male or female?
0:47:43 > 0:47:45- Female.- Beautiful.
0:47:45 > 0:47:48- Lovely tracks.- It came this way from this grassland here.
0:47:48 > 0:47:51So probably going to look for some deer?
0:47:51 > 0:47:52Yes, probably.
0:48:00 > 0:48:04You've never had an accident with them? You managed to get away obviously?
0:48:04 > 0:48:07Yeah, nearly, nearly, many times, but not yet.
0:48:07 > 0:48:09Yes.
0:48:09 > 0:48:11- Right, I'll stick with you then.- OK.
0:48:11 > 0:48:13I don't want to lose you here.
0:48:13 > 0:48:17Yeah. Good, I don't want you to lose me here either!
0:48:18 > 0:48:22OK, so we'll go a little bit up and check whatever there.
0:48:30 > 0:48:32See the tall grass?
0:48:32 > 0:48:34Could be there somewhere.
0:48:36 > 0:48:38That's the ideal sort of hiding place then, is it?
0:48:38 > 0:48:42Yes, that's quite a good place for the tigers.
0:48:42 > 0:48:45Also here it's quite good because we have here safe area.
0:48:45 > 0:48:48So you always keep an eye out for trees?
0:48:48 > 0:48:51Yeah, keep an eye on tree.
0:48:51 > 0:48:52So we'll call that one Steve's tree.
0:48:52 > 0:48:55- Steve's tree, OK. - OK. Which one's Dan's tree?
0:48:55 > 0:48:57That one.
0:49:05 > 0:49:08- Steve, are you coming? - Yes, yeah, yeah, I'm still here.
0:49:10 > 0:49:12This is a very dangerous place.
0:49:12 > 0:49:15I wish he wouldn't keep saying that!
0:49:29 > 0:49:34Now, I understand this obviously is a dangerous place to walk around on foot for a human.
0:49:34 > 0:49:37What's it like for our geese? Is it dangerous for them?
0:49:37 > 0:49:42Pretty dangerous for them too, because we have lots of predators
0:49:42 > 0:49:47- like jackals, jungle cat, bird of prey, so many things.- Yeah.
0:49:47 > 0:49:50So they have to keep their eyes and ears open?
0:49:50 > 0:49:52They have to be careful too, yes.
0:49:53 > 0:49:56So, although Royal Chitwan is lush and beautiful,
0:49:56 > 0:50:01this is a very dangerous place for the birds to come to at the end of their migration.
0:50:01 > 0:50:05There are so many potential predators out to get them.
0:50:14 > 0:50:18If the geese didn't get driven away because of the extreme cold in winter,
0:50:18 > 0:50:25they would probably be much better off staying in Tibet all the year round, never migrating at all.
0:50:25 > 0:50:27But they have no choice.
0:50:30 > 0:50:36I know how they do it and now I know why they do it.
0:50:36 > 0:50:39There's just one final question -
0:50:39 > 0:50:41are they going to do it?
0:50:52 > 0:50:56Right now, I'm getting concerned we may never find out,
0:50:56 > 0:51:01because the transmitters' batteries are due to fail any time now.
0:51:01 > 0:51:04The ten months is very nearly up.
0:51:04 > 0:51:06And once they switch off,
0:51:06 > 0:51:07it's game over.
0:51:22 > 0:51:27In any normal year, the geese would have arrived here long before now,
0:51:27 > 0:51:31but this year they are late, getting on very late.
0:51:35 > 0:51:38We're scouring the park day in, day out.
0:51:38 > 0:51:42There's not a sign of a single goose.
0:51:55 > 0:52:00There are actually only around 18,000 pairs of bar-headed geese left in the world.
0:52:00 > 0:52:03They are very nearly an endangered species.
0:52:06 > 0:52:09And because there are so few, the fact that they haven't managed
0:52:09 > 0:52:13to cross the mountains yet is concerning.
0:52:13 > 0:52:16They're late, they're very late,
0:52:16 > 0:52:20which is disappointing for our film but it's actually even more worrying just for them
0:52:20 > 0:52:22because it isn't a big population.
0:52:22 > 0:52:26I hope they're OK.
0:52:33 > 0:52:35I'm having to get my head around the idea
0:52:35 > 0:52:39that I'll never find out what happened to Hillary and Tenzing.
0:52:39 > 0:52:43And I have to say, after all I've been through to try and follow their story,
0:52:43 > 0:52:45it's a hard thought to swallow.
0:52:50 > 0:52:55But, just when we thought it was all over, we're back in business.
0:52:59 > 0:53:04Just before the transmitters stopped working - and I do mean just before,
0:53:04 > 0:53:08it was only a matter of a few days - Hillary and Tenzing made their move.
0:53:08 > 0:53:11They crossed the Himalayas, but, true to form,
0:53:11 > 0:53:13they're still not following the script.
0:53:13 > 0:53:15They didn't stop in Nepal,
0:53:15 > 0:53:19they headed on and on, all the way to here - India.
0:53:24 > 0:53:26We know exactly where they landed,
0:53:26 > 0:53:29but now the transmitters have switched off
0:53:29 > 0:53:32and stopped transmitting for ever.
0:53:35 > 0:53:39- So what the- BLEEP- are we going to do?
0:53:46 > 0:53:50I've come too far and suffered too much.
0:53:50 > 0:53:52I'm simply not prepared to give up now.
0:53:52 > 0:53:56But I have to say, it's beginning to feel like mission impossible.
0:54:09 > 0:54:12There's just one more final possibility.
0:54:12 > 0:54:16When battery power fails, people power has to take over.
0:54:23 > 0:54:27This is a really rural part of India.
0:54:27 > 0:54:32People are out working in the fields from dawn to dusk.
0:54:44 > 0:54:48Is it possible someone has seen Hillary or Tenzing?
0:54:48 > 0:54:53THEY SPEAK LOCAL LANGUAGE
0:54:59 > 0:55:06They were sitting around the area of the river where he spends a lot of time.
0:55:06 > 0:55:10He saw them flying by at sort of eye level.
0:55:10 > 0:55:13When I spoke to him on that day, that's what he said.
0:55:13 > 0:55:17So did he understand it was a bar-headed goose or does he not
0:55:17 > 0:55:19really have an interest in birds?
0:55:19 > 0:55:22I showed him the birds and he said, "Oh, yeah, there were
0:55:22 > 0:55:26"three or four. One of them had a red band around its neck".
0:55:26 > 0:55:32And that pretty much identifies the bird because now I've shown him
0:55:32 > 0:55:37the bird in the bird book and it is the same bird.
0:55:37 > 0:55:39That hardly seems possible.
0:55:39 > 0:55:42In the vastness of India,
0:55:42 > 0:55:46we have an eyewitness who's actually seen Hillary.
0:55:55 > 0:55:58Could Hillary still be here?
0:55:58 > 0:56:02And where exactly did she finally choose to end her migration?
0:56:15 > 0:56:21I'm using a handheld GPS to find the exact spot Hillary made her final transmission.
0:56:35 > 0:56:37Well, this is the place.
0:56:37 > 0:56:43This is where, before her transmitter turned off, the last fix we got for Hillary was here.
0:56:43 > 0:56:47Well, it was within a stone's throw of this very position.
0:56:47 > 0:56:50And not only that, we've got an eye-witness account.
0:56:50 > 0:56:53Someone has actually clapped eyes on that red collar of hers.
0:56:53 > 0:56:57So we can say for definite she made it.
0:56:59 > 0:57:02Hillary chose well.
0:57:02 > 0:57:06This is probably a far better bet than the dangers of Royal Chitwan.
0:57:06 > 0:57:09There's no possibility of being ambushed by tigers or jackals.
0:57:16 > 0:57:19Hillary and Tenzing have led me a merry dance.
0:57:19 > 0:57:23But because of this project, we're just that little bit closer
0:57:23 > 0:57:27to understanding the extraordinary world of the bar-headed goose.
0:57:32 > 0:57:36And now that I've discovered for myself exactly what these geese
0:57:36 > 0:57:41actually go through, I have nothing but respect for these truly extreme animals.
0:57:43 > 0:57:45And even though I didn't find them,
0:57:45 > 0:57:50it's enough to know that Hillary and Tenzing did definitely make it.
0:57:54 > 0:57:59But, wherever they may be now, these two extraordinary geese
0:57:59 > 0:58:02are still writing their own stories.
0:58:43 > 0:58:45Subtitles by Red Bee Media Ltd, 2006
0:58:45 > 0:58:48E-mail subtitling@bbc.co.uk