0:00:02 > 0:00:07*
0:00:36 > 0:00:38Sparrows...
0:00:38 > 0:00:42in South Africa. Like all sparrows, they eat most things -
0:00:42 > 0:00:46insects, fruit and, particularly, seeds.
0:00:46 > 0:00:54And they convert that diet into their own flesh, which is the richest of all foods - meat.
0:00:54 > 0:00:57So they themselves are much hunted.
0:00:57 > 0:01:00A falcon is also looking for a meal.
0:01:21 > 0:01:24And it has one.
0:01:51 > 0:01:58Meat is such a rich food that a falcon need only kill once a day to sustain itself.
0:01:58 > 0:02:04So, plenty of time for sitting around. Nice work if you can get it.
0:02:04 > 0:02:09But getting it is not necessarily all that easy.
0:02:09 > 0:02:12This hillside in New Zealand may look bare,
0:02:12 > 0:02:19but, in fact, I'm sitting in the middle of an immense, active colony of shearwaters.
0:02:19 > 0:02:22The adults are out at sea, fishing,
0:02:22 > 0:02:27but these are their burrows and inside almost every one,
0:02:27 > 0:02:30there's a fat, juicy chick...
0:02:30 > 0:02:34and THIS bird knows it.
0:02:35 > 0:02:38This is a parrot, a kea.
0:02:38 > 0:02:42Not the sort of parrot that is content with fruit and nut.
0:02:42 > 0:02:47Its beak can certainly cope with such things,
0:02:47 > 0:02:51but it can also give a bite that kills.
0:02:51 > 0:02:56The keas tour the shearwaters' burrows, listening.
0:02:56 > 0:02:59SQUEALS
0:03:06 > 0:03:09They've heard something...
0:03:09 > 0:03:14a shearwater chick is moving in its underground nest chamber.
0:03:21 > 0:03:25But the tunnel is too narrow for them.
0:03:26 > 0:03:31If they want the chick, they will have to dig for it.
0:03:59 > 0:04:03Keas became meat-eaters relatively recently,
0:04:03 > 0:04:08and have no special adaptations to help them find their victims.
0:04:08 > 0:04:15Other birds who began to eat meat much earlier have very sophisticated ways of locating their targets.
0:04:17 > 0:04:21The great grey owl hunts in the Arctic.
0:04:21 > 0:04:27In summer, it hardly gets dark, but the owl's prey is largely invisible,
0:04:27 > 0:04:29for it's hidden beneath the snow.
0:04:34 > 0:04:39Like the kea, the owl listens for its victims.
0:04:39 > 0:04:46But its hearing is many times more sensitive than the kea's, and ten times better than ours.
0:04:48 > 0:04:53The feathered discs on either side of its face act like ear trumpets.
0:04:53 > 0:04:58Each shields the ear on one side from sound coming from the other,
0:04:58 > 0:05:02so the owl can scan the landscape in stereo.
0:05:09 > 0:05:13It has detected a faint rustle beneath the snow -
0:05:13 > 0:05:16made by a lemming.
0:05:35 > 0:05:40Invisibility was insufficient protection for the lemming.
0:05:40 > 0:05:46The great grey owl's amazing hearing enables it to hunt the year round,
0:05:46 > 0:05:51even through the Arctic winter, when it's dark for weeks on end.
0:05:51 > 0:05:56Elsewhere, other owls locate their prey with a different sense - vision.
0:05:56 > 0:06:03The bigger the eye, the more light it gathers, so the better it functions at very low light levels.
0:06:03 > 0:06:09These eyes are so big that they can't revolve in their sockets.
0:06:09 > 0:06:12They belong to a scops owl.
0:06:19 > 0:06:22They perceive shape not colour,
0:06:22 > 0:06:26so a scops owl sees a soot and whitewash world,
0:06:26 > 0:06:31a world that most other birds would find impenetrably dark.
0:06:40 > 0:06:42Without colour,
0:06:42 > 0:06:46it's movement that betrays the presence of prey.
0:07:01 > 0:07:02A spider -
0:07:02 > 0:07:08big enough and succulent enough to provide a snack for a scops.
0:07:09 > 0:07:14And that is what it will be if it moves.
0:07:39 > 0:07:43Daytime hunters, like these buzzards,
0:07:43 > 0:07:45have vision of a different kind.
0:07:50 > 0:07:55During the breeding season, they feed mainly on young rabbits.
0:07:55 > 0:07:57If there is plenty of light,
0:07:57 > 0:08:01an eye can become virtually a telescope
0:08:01 > 0:08:06and buzzards can spot a rabbit from over a mile away...if it moves.
0:08:14 > 0:08:17They also see it in full colour.
0:08:17 > 0:08:22With such acute distant vision, a buzzard can survey a great area
0:08:22 > 0:08:26without moving from its perch.
0:08:26 > 0:08:30Rabbits feeding beside their warren.
0:08:30 > 0:08:34They would be unwise to venture far from their holes.
0:08:38 > 0:08:43The buzzard has detected a chance and is in the air.
0:08:43 > 0:08:49From 300 feet above the ground, it can see each rabbit very clearly.
0:09:31 > 0:09:35No luck this time - for the buzzard.
0:09:35 > 0:09:40The great majority of a buzzard's attacks are failures,
0:09:40 > 0:09:47but the energy spent on an attempt such as this was not great and the wind carries it back aloft.
0:09:51 > 0:09:56The kestrel - little more than half the size of the buzzard.
0:09:56 > 0:09:59It seeks much smaller prey - voles.
0:09:59 > 0:10:03Its colour vision is also excellent - better than ours.
0:10:03 > 0:10:08It spans more of the spectrum, extending into the ultraviolet,
0:10:08 > 0:10:15so the blue of the sea around the Cornish coast appears more intense to a kestrel than it does to us.
0:10:15 > 0:10:22For a long time, no-one understood how, or indeed IF, that might help it to hunt.
0:10:22 > 0:10:25Now, we're beginning to get clues.
0:10:25 > 0:10:28The voles a kestrel seeks
0:10:28 > 0:10:33seldom leave the shelter of their tunnels in the grass during the day.
0:10:35 > 0:10:39They mark their tracks with droplets of urine,
0:10:39 > 0:10:44and urine, in ultraviolet light, is very conspicuous.
0:10:44 > 0:10:50So with ultraviolet vision, the kestrel can SEE the signposts
0:10:50 > 0:10:52that the voles can only smell.
0:10:57 > 0:11:02As a consequence, the kestrel knows just where to focus its attention.
0:11:40 > 0:11:43And that was a success.
0:11:45 > 0:11:49The open skies above the wide plains of Africa.
0:11:50 > 0:11:52Vultures.
0:11:52 > 0:11:58They also eat meat, but only that which has been slaughtered by others.
0:11:59 > 0:12:03They, too, rely on keen eyesight to find their meals.
0:12:04 > 0:12:12Their eyes are so acute, they can keep watch over the plains from more than a thousand feet up.
0:12:15 > 0:12:22The warm columns of air rising from the baking ground and captured by their broad wings
0:12:22 > 0:12:27carries them up to great heights with little expenditure of energy
0:12:27 > 0:12:30and supports them there.
0:12:37 > 0:12:40They scan the ground beneath them,
0:12:40 > 0:12:44but they also keep a sharp eye on one another.
0:13:09 > 0:13:15A lappet-faced vulture is on the ground beside a carcass.
0:13:16 > 0:13:21Griffon vultures have noticed it and have started to wheel downwards.
0:13:23 > 0:13:28Others have already joined the lappet-faced around the kill.
0:13:30 > 0:13:33As more birds glide down,
0:13:33 > 0:13:38their descent is noticed from miles away in all directions.
0:13:38 > 0:13:42And the news that a kill has been discovered
0:13:42 > 0:13:46spreads across the network of watchers in the sky.
0:14:06 > 0:14:12More and more start circling downwards towards the banquet.
0:14:46 > 0:14:53Within a few minutes, the carcass is submerged beneath a dense scrum of struggling birds.
0:14:55 > 0:15:00With no feathers on heads and necks, they do not unduly soil themselves
0:15:00 > 0:15:05as they plunge their heads deep into the carcass.
0:15:05 > 0:15:08And still more come.
0:15:08 > 0:15:13The big cats may make most of the kills on the Serengeti,
0:15:13 > 0:15:19but most of the meat on the plains is eaten, not by lions and leopards,
0:15:19 > 0:15:21but by vultures.
0:15:28 > 0:15:34To human nostrils, the stench of corruption here is overwhelming.
0:15:34 > 0:15:38But these vultures are impervious to it. They can't sense it.
0:15:38 > 0:15:42It was their sharp vision that brought them here.
0:15:48 > 0:15:52But there's one bird that, exceptionally,
0:15:52 > 0:15:56has an extremely acute sense of smell.
0:15:56 > 0:15:58Here in the rain forest of Trinidad,
0:15:58 > 0:16:03there is an almost unbroken ceiling of leaves above me.
0:16:03 > 0:16:10No bird flying above that could possibly see a piece of meat like this lying on the forest floor.
0:16:10 > 0:16:14But this is an extremely smelly piece of meat.
0:16:15 > 0:16:17Let me...
0:16:17 > 0:16:19hide it.
0:16:26 > 0:16:31I can keep watch from a hill that rises above the canopy.
0:16:31 > 0:16:34Not a bird in sight.
0:16:44 > 0:16:47But there's one - a turkey vulture.
0:16:47 > 0:16:49And another.
0:16:52 > 0:16:59It's a turkey vulture because its head is not black like the other kind of vulture here, but red.
0:16:59 > 0:17:05And it's always the turkey vultures that are on the scene first.
0:17:05 > 0:17:08The meat I put down is directly under there,
0:17:08 > 0:17:15and already - it's less than three-quarters of an hour ago - they are beginning to assemble.
0:17:16 > 0:17:22It's almost unbelievable that the smell from that small piece of meat
0:17:22 > 0:17:27could have drifted up through the canopy and so permeate the air
0:17:27 > 0:17:31that it can be detected half a mile away,
0:17:31 > 0:17:38and it's equally astonishing that the birds are able to measure its relative strength with such accuracy
0:17:38 > 0:17:46that they can trace it back to its source simply by sensing in which direction it becomes stronger.
0:17:46 > 0:17:51But the turkey vulture has wide-open nostrils
0:17:51 > 0:17:56and extremely well-developed sense organs within them.
0:18:14 > 0:18:17But it's getting close.
0:18:17 > 0:18:19There's something in there somewhere.
0:18:51 > 0:18:53Got it!
0:18:59 > 0:19:04Their beaks are quite adequate for tearing off strips of flesh,
0:19:04 > 0:19:09and vultures, after all, do not kill the animals that they eat.
0:19:09 > 0:19:14But those that do must have much more powerful weapons.
0:19:31 > 0:19:36Few animals can survive the grasp of these massive talons.
0:19:36 > 0:19:40They belong to the African crowned eagle.
0:19:40 > 0:19:43It is huge - nearly three feet long.
0:19:43 > 0:19:47It can kill prey over four times its own weight.
0:19:47 > 0:19:54It hunts over the East African forest and seeks, particularly, monkeys.
0:19:54 > 0:20:01Vervet monkeys seldom expose themselves by venturing into the very highest branches,
0:20:01 > 0:20:03so hunting them is not easy.
0:20:10 > 0:20:16The eagle has relatively short wings for its great size,
0:20:16 > 0:20:19which helps it to plunge through the canopy.
0:20:33 > 0:20:36MONKEYS CALL
0:21:09 > 0:21:12The vervets have a special call
0:21:12 > 0:21:17that warns the whole troop that danger threatens.
0:21:42 > 0:21:45It's caught a monkey.
0:21:51 > 0:21:56Its mate joins it, and together, they return to their nest.
0:22:21 > 0:22:24The chick is only a few days old,
0:22:24 > 0:22:28too young to tear apart the prey for itself.
0:22:42 > 0:22:46It has a lot of growing to do and a huge appetite.
0:22:46 > 0:22:51The adults will have to feed it for four months before it can fly,
0:22:51 > 0:22:57for nine months after that before it's strong enough to hunt itself.
0:22:57 > 0:23:04To keep themselves properly fed, a pair of crowned eagles need a large hunting ground to themselves,
0:23:04 > 0:23:09so all eagles defend their territories with great vigour.
0:23:13 > 0:23:16This one, a sea eagle,
0:23:16 > 0:23:22is patrolling a forested coast in Malaysia along which it fishes daily.
0:23:22 > 0:23:26Those that live in the air have to fight in the air,
0:23:26 > 0:23:31and eagles do so with their primary weapons - their talons.
0:24:39 > 0:24:43Lake Bogoria in the African Rift Valley -
0:24:43 > 0:24:47a soda lake fed by hot volcanic springs.
0:24:48 > 0:24:52At first sight, a ferociously inhospitable place.
0:24:52 > 0:24:55And it is - for most creatures.
0:24:55 > 0:25:00But although no fish can live in its tepid soda-laden waters,
0:25:00 > 0:25:05it is nonetheless packed with food for fish eagles.
0:25:09 > 0:25:11A million flamingos.
0:25:37 > 0:25:43Here, the food chain sustaining a meat-eater could scarcely be shorter.
0:25:43 > 0:25:48Microscopic plants, algae, that can uniquely tolerate these salty waters
0:25:48 > 0:25:50multiply in the sunshine by the ton.
0:25:50 > 0:25:58Flamingos filter the algae from the water with their beaks - and vegetable is turned into flesh.
0:25:58 > 0:26:01And that flesh is food for eagles.
0:26:33 > 0:26:37The flamingos have to go into the shallows
0:26:37 > 0:26:42to drink from a spring that provides the only fresh water in the lake.
0:26:42 > 0:26:46But here they are very vulnerable.
0:26:46 > 0:26:51As the eagle nears, the flamingos stampede into deeper water.
0:26:51 > 0:26:54The eagle won't tackle them there
0:26:54 > 0:26:59because it has difficulty carrying anything much bigger than a fish,
0:26:59 > 0:27:04so it can only eat a flamingo in the shallows or on the shore.
0:27:15 > 0:27:19This concentration of prey is so dense,
0:27:19 > 0:27:27that pairs of fish eagles have been able to establish themselves every mile or so around the lake margins.
0:27:27 > 0:27:29But even this number of hunters
0:27:29 > 0:27:34has little effect on the size of the flamingo population.
0:28:11 > 0:28:16Fish eagles normally snatch fish from the surface of the water,
0:28:16 > 0:28:20they don't usually tackle a bird on the wing.
0:28:20 > 0:28:22But there is no need to do so here.
0:28:40 > 0:28:45Now it has to drag its victim to the shore.
0:29:07 > 0:29:12Few hunters can have a greater concentration of prey
0:29:12 > 0:29:14continuously at their disposal.
0:29:14 > 0:29:18The flamingos are back in the shallows.
0:29:22 > 0:29:27It would be difficult to imagine a more barren hunting territory
0:29:27 > 0:29:32than this lava field in the volcanic islands of the Galapagos.
0:29:32 > 0:29:36But there's a bird that finds its prey even here.
0:29:42 > 0:29:46Although there is little vegetation on land,
0:29:46 > 0:29:52there is a lot around the coast. And these marine iguanas graze on it.
0:29:52 > 0:29:55They can even swim down to the sea bed to do so.
0:29:55 > 0:30:00There they are unreachable by hunting birds.
0:30:00 > 0:30:05But they come out of the sea onto the rocks to rest and to warm up.
0:30:05 > 0:30:08The big ones are too big and strong for a hawk,
0:30:08 > 0:30:13the small ones can scuttle away and hide in a crack,
0:30:13 > 0:30:18but the females, at one time of the year, are vulnerable.
0:30:23 > 0:30:29The Galapagos hawks know exactly when that is - the breeding season,
0:30:29 > 0:30:35when the female iguanas go onto the few sandy beaches to lay their eggs.
0:30:35 > 0:30:39Here, they can dig the holes they need.
0:30:48 > 0:30:53Hawks all over the island keep watch beside the few beaches.
0:31:27 > 0:31:32When the iguana has finished digging and laying, she must be tired,
0:31:32 > 0:31:35so the hawk then has its best chance.
0:31:35 > 0:31:38But even so, iguanas can run very fast indeed.
0:31:53 > 0:31:58If the iguana can reach the rocks, she will be safe.
0:32:06 > 0:32:10This one retreats into the burrow she has just dug.
0:32:10 > 0:32:14She'll have to try and escape later.
0:32:30 > 0:32:35The outcome is by no means certain - the iguana is still extremely strong.
0:32:42 > 0:32:45But not strong enough.
0:32:58 > 0:33:03A number of hawks take advantage of this bounty.
0:33:19 > 0:33:23Wounded though it is, this one can still run.
0:33:30 > 0:33:33The hawk has lost this encounter.
0:33:33 > 0:33:38It can't catch an iguana once it has reached its burrow,
0:33:38 > 0:33:42even though it might still be able to see it.
0:33:46 > 0:33:50But some hawks are specially equipped
0:33:50 > 0:33:54for snatching their prey from deep within holes.
0:33:56 > 0:33:58This is the African harrier hawk.
0:34:11 > 0:34:15Its legs are particularly long.
0:34:22 > 0:34:28Crucially, they're double-jointed, so that they can bend backwards -
0:34:28 > 0:34:33invaluable when groping in a nest hole, trying to extract a chick,
0:34:33 > 0:34:36as this young bird is doing.
0:35:09 > 0:35:11No luck.
0:35:12 > 0:35:18But the adult, seeking lizards in the rocks, is more persistent.
0:36:02 > 0:36:05It swallows its lizard whole.
0:36:10 > 0:36:15This lizard, however, has been caught by a shrike -
0:36:15 > 0:36:19a much smaller bird and too small to swallow such prey,
0:36:19 > 0:36:26but neither its beak nor its claws are powerful enough to tear its victim's body apart.
0:36:31 > 0:36:36The acacias of Africa provide all the hooks and spikes
0:36:36 > 0:36:40that such a bird could need for butchery.
0:37:08 > 0:37:14Prey as small as beetles and as big as stoats are treated this way.
0:37:14 > 0:37:19Some of the larger animals are left on their skewers, like hung game,
0:37:19 > 0:37:21so that decay loosens their flesh.
0:37:21 > 0:37:24Stocks are sometimes built up
0:37:24 > 0:37:27to last a shrike through hard times.
0:37:27 > 0:37:32But often the temptation of fresh meat is irresistible.
0:37:39 > 0:37:42The lammergeier actually eats bones,
0:37:42 > 0:37:48but breaking up a large skeleton is an even bigger problem.
0:37:49 > 0:37:52A lammergeier, hefty though it is,
0:37:52 > 0:37:56has not got the beak or claws to do that job.
0:37:56 > 0:38:01But, like the shrike, it knows a trick or two.
0:38:20 > 0:38:23It doesn't just drop a bone anywhere.
0:38:23 > 0:38:27It has its favourite patches of bare rock -
0:38:27 > 0:38:32though sometimes its aim is not as good as it might be.
0:38:42 > 0:38:46It's getting a few splinters off this bone.
0:38:46 > 0:38:49It can swallow even the sharpest fragment,
0:38:49 > 0:38:55for its powerfully acid digestive juices dissolve the bone rapidly.
0:39:12 > 0:39:15The greatest prize is the marrow,
0:39:15 > 0:39:19so the big bones have to be well and truly split,
0:39:19 > 0:39:21and that takes perseverance.
0:39:21 > 0:39:29A lammergeier may have to drop a bone up to 50 times before it hits rock at the right angle to split it.
0:39:37 > 0:39:41The bodies of other animals provide such rich food
0:39:41 > 0:39:43that a bird doesn't need much of it.
0:39:43 > 0:39:47But getting it demands not only skill,
0:39:47 > 0:39:49but often a great deal of effort.
0:39:51 > 0:39:54An English wood is full of such food,
0:39:54 > 0:39:58but the dense cover makes things difficult.
0:39:58 > 0:40:03But there is one bird that specialises in hunting here.
0:40:03 > 0:40:06It flies very fast, very low,
0:40:06 > 0:40:09and takes its victims by surprise.
0:40:11 > 0:40:17This is one of its favourite hunting places - an old overgrown orchard
0:40:18 > 0:40:23where woodland birds feed on rotting apples, and the grubs they attract.
0:40:33 > 0:40:36A sparrowhawk visits the wood every day
0:40:37 > 0:40:40and waits for just the right moment.
0:40:58 > 0:41:03It knows every twist and turn in its approach flight -
0:41:03 > 0:41:08it has flown it often enough before, sometimes two or three times a day.
0:41:10 > 0:41:13Its short rounded wings and long tail
0:41:13 > 0:41:18enable it to fly at speed through really narrow gaps.
0:41:45 > 0:41:49Warning calls alert the whole woodland.
0:41:49 > 0:41:53ASSORTED BIRD CRIES
0:41:56 > 0:42:02This time, it wasn't quick enough to catch the bird community by surprise.
0:42:04 > 0:42:08This hunter is six times heavier than a sparrowhawk.
0:42:08 > 0:42:13It's a goshawk and it hunts not only birds, but mammals.
0:42:13 > 0:42:16A brown rat.
0:42:16 > 0:42:21The goshawk, like the sparrowhawk, can manoeuvre through narrow gaps,
0:42:21 > 0:42:27but it also has another way of hunting in the woodlands.
0:42:33 > 0:42:36It will pursue the rat on foot.
0:43:15 > 0:43:20Even though hunters have a formidable armoury and great skill,
0:43:20 > 0:43:25most of their hunting trips, like this one, end in failure.
0:43:26 > 0:43:29The coast of Cornwall -
0:43:29 > 0:43:34territory of one of the most highly specialised of all hunting birds.
0:43:34 > 0:43:39These are one of its favourite prey - pigeons.
0:43:39 > 0:43:45High in the sky, so high it's almost invisible, a peregrine is watching.
0:43:56 > 0:43:59Pigeons fly fast.
0:44:02 > 0:44:05The peregrine starts its attack.
0:44:12 > 0:44:16Wings drawn back, it's travelling at 200mph.
0:44:29 > 0:44:34Striking its victim with its talons at this speed brings instant death.
0:44:41 > 0:44:44The peregrine returns to its nest.
0:44:58 > 0:45:02It has two eager customers for the meat.
0:45:05 > 0:45:09An adult peregrine must kill several times a day
0:45:09 > 0:45:13if its chicks are to be kept adequately fed.
0:45:25 > 0:45:32Five weeks will pass before the chicks are fully fledged and ready for their first flight.
0:45:32 > 0:45:35They start with experimental outings,
0:45:35 > 0:45:39getting used to the feel of the air.
0:45:40 > 0:45:43Another youngster watches.
0:45:49 > 0:45:56Ten days later and the young birds are feeling confident enough to tease a passing seagull.
0:46:05 > 0:46:11The high-speed aerial pounce - the peregrine's special killing tactic -
0:46:11 > 0:46:14takes a lot of learning.
0:46:19 > 0:46:25In mid-air, you must throw your legs forwards with talons outstretched...
0:46:25 > 0:46:30and your sibling's tail makes a good practice target.
0:46:34 > 0:46:38Now three youngsters join together in the game.
0:46:43 > 0:46:47They perfect the manoeuvre that launches a dive -
0:46:47 > 0:46:54the roll and the pumping of the wings with which the peregrine generates its unique speed.
0:47:01 > 0:47:06Tumbling and rolling, diving and striking, it may seem like play,
0:47:06 > 0:47:13but like so much play, it's practice for the serious business of adult life.
0:47:24 > 0:47:28And now, a lesson for advanced students only.
0:47:28 > 0:47:35An adult joins the youngsters carrying in its talons a pigeon - wounded but still alive.
0:47:35 > 0:47:41And the youngster takes it to make its very first kill.
0:47:41 > 0:47:46In a month, it will become the swiftest of all the world's hunters.
0:47:48 > 0:47:53But only about a third of the earth is covered by land,
0:47:53 > 0:47:58the rest is covered by water. There is plenty of food there, too,
0:47:58 > 0:48:02but you have to learn different techniques to go fishing -
0:48:02 > 0:48:07as we'll see in the next programme in The Life Of Birds.
0:48:43 > 0:48:47Subtitles by Gillian Frazer BBC Scotland 1998