The Life of Birds (1998) s01e05 Episode Script

Birds are masters of the air and can gather food from anywhere on the land.
But most of the earth is covered with water and so some birds, early in their history, became extremely competent there too, both in it and on it.
These shallow gravelly streams here, in the New Zealand Alps seem desolate places devoid of any food.
But look at the underside of this pebble I've just picked up; Several succulent insect larvae.
And in fact, these streams, like waters fresh or salt all over the world, are full of food.
When you consider that two thirds of the world is covered with water, that's a huge resource.
No group of animals living out of water have developed a wider range of techniques, and indeed tools for, collecting that food than the birds.
This one is unique.
The only beak in the entire bird world that is bent to one side.
This is the wrybill, which only lives here in New Zealand.
Its extraordinary beak enables it to probe beneath large heavy boulders that it couldn't possibly turn over or even shift.
And just in case you're wondering, the bend is always to the right.
Dippers plunge right into the streams.
This one is in Yellowstone, in the American West, where hot volcanic springs keep the streams clear of ice in winter, so that the dippers can walk underwater throughout the year.
Their dense, oily plumage retains air to such a degree that it forms a silvery cloak around their body and so keeps the birds warm.
The disadvantage of that coat of air is that it makes its wearer very buoyant, and the dipper has to struggle hard to remain below the surface.
They seldom manage to stay underwater for much more than a quarter of a minute at a time.
Kingfishers are only underwater for a second or so.
They are living harpoons.
This is one of the bigger members of the family, the belted kingfisher.
It's the size of a small crow, and lives beside rivers and lakes all over North America.
Understandably, it prefers places where the water is clear so it can get a good view of its targets.
Having caught the fish, it must now stun it, and to do that the fish has to be head outwards.
But if the kingfisher is to swallow it without the spiny fins sticking in its throat, it has to turn the fish around again.
Most kingfishers dive from perches.
That means that they are more or less tied to the shore.
0nly one of them is able to break that link.
This is the African pied kingfisher, and it can launch its dive from high in the sky because, even in completely still air, it can hover.
It's the biggest bird in the world to be able to do this.
It's not only a diver, sometimes it's a juggler.
The darter does its harpooning underwater.
It's so at home there, that it can actually creep up on its prey.
Missed.
It always has to juggle to get its catch off its harpoon.
The darter doesn't have the dipper's problem with buoyancy because its feathers actually absorb water.
But that means that it gets soaked to the skin, and after a swim, like anyone in a wet bathing costume, it has to dry itself quickly and thoroughly if it's not to get a chill.
Some fish are incurably inquisitive.
The little egret can attract them by doing no more than waggle its yellow feet.
It seems a simple enough trick, but it works nonetheless.
Birds all over the world have devised all kinds of bizarre solutions to the problem of extracting little fish from shallow pools.
In the swamps of Florida, the reddish egret performs an improbable kind of dance.
The idea seems to be to frighten the little fish out of their hiding places.
Shading your eyes can help you see what's down there, beneath the reflections.
And there was something.
In Africa, the black heron takes the business of shading its eyes very seriously indeed.
Maybe cutting out reflections is not the only reason for doing this.
Many fish prefer to swim beneath an overhanging bank or a tree, so they can't be easily seen from above.
So perhaps they deliberately take shelter under the heron's wings, which, of course, could be a mistake.
The spoonbill isn't really after fish.
This scything action of its beak enables it to gather tadpoles, beetles and insect larvae, but it must also scare little fish, which then dash off to seek safety.
So it's worthwhile for the black heron to follow the spoonbill around, just in case.
The pygmy cormorant certainly is after fish, and therefore thinks it's a good idea to follow the heron.
Maybe the heron is having better luck.
All in all, a little fish doesn't stand much of a chance in a shallow pool like this.
These too are fishermen, but they don't wade, they skim.
And to do that they need not long legs, but a long beak.
0r to be more accurate, a long, lower mandible.
The upper one is more or less normal in size.
This is the skimmer, a highly specialised relation of the gulls.
Their chicks, in fact, look very like gull chicks.
They don't develop that extraordinary beak until they are some three months old.
Skimming, although it demands flying of the greatest precision, is straightforward enough in principle.
As soon as the lower mandible, ploughing through the surface of the water, touches anything solid, a reflex action will make it snap shut.
That sounds fine, but supposing the beak hits something really big, like a floating twig or, worse, a submerged rock, what then? Well, the fact is, that quite a lot of skimmers have broken mandibles.
Whatever the hazards, overall, the technique is a very succesful one.
The chicks have to be fed for six weeks and skimmers are faithful, hardworking parents, bringing food every ten minutes or so, for hours on end when the fishing is good.
But while they are certainly devoted to their young, they are sometimes just a little optimistic.
0h well, if baby doesn't want it.
Skimmers and egrets and kingfishers live beside the water.
Some birds live actually on it.
Mallards must be one of the most familiar birds in the world.
Because of that, perhaps we tend to take ducks for granted.
But in fact, they are a very varied family.
Different species are adapted to different ways of life on water.
Mallards, for example, are specialist dabblers.
They find all the food they need by doing no more than dipping their heads beneath the surface.
And there's lots of food to be found that way; duckweed, tadpoles, weeds and seeds, and bits of bread thrown in by friendly humans.
If the food they have spotted is really deep down, they will up-end totally.
If that doesn't get it, it's beyond their reach and that's that.
Ducks keep their plumage water-resistant by anointing it with oil from a gland on their rump.
They also keep their feathers clean, soft and pliant by frequent and enthusiastic bathing.
Ducks don't alljust dabble.
Some dive deeper.
The merganser has webbed feet, like the mallard and all other ducks, but they are placed very far back on the body.
That's the best place to have a propeller from a mechanical point of view, and as a result they can swim quite fast enough to catch small fish.
Their bills are notched like a fine saw, which helps when you have to grapple with a slippery fish.
The young start diving almost as soon as they've hatched.
But they're still covered in down, and that makes swimming underwater very difficult indeed.
They use up far more energy than their streamlined parents do.
The most skilful underwater swimmer of all freshwater birds, however, is the diver.
This is an immature one, that has not yet got its spectacular black and white plumage.
Its feet are placed so far back on its body, that out of water it can hardly walk, but underwater it's superbly manoeuvrable.
Small fish have little chance.
That's very useful for keeping warm, it can be very windy out there on the lake.
But as the mergansers demonstrated, it causes problems when diving.
And young divers don't even try.
Diver chicks, it has to be said, are rather pampered.
They're regularly given lifts.
And while one of their parents ferries them around, the other finds food for them.
The male finds a fish, but decides to eat that himself.
He's been away a long time and the family is getting hungry.
But now he's found a crayfish.
That will do for them.
The crayfish is carefully broken up, and passed over to the chicks a little piece at a time, with great delicacy, and quite a lot of patience.
They get shallower as rivers dump sediment in them, and in the tropics, they may even dry up every year.
As a result, all sorts of delicious things come within reach, as they have in this African pool The openbill stork has a special liking for mussels, and a special way of opening them.
First, a sharp squeeze to make the shell open slightly.
Then the lower mandible is slipped in, to cut the body away from the shell.
After that, it's easy.
Snails require a slightly different treatment.
To start with, they have to be taken on to solid ground.
Now the little disc, with which the snail can seal its shell, has to be removed.
That's done by delicately squeezing it in just the right place.
There! Then, once again, the muscle that attaches the snail to its shell has got to be severed.
And out it comes.
As the dry season progresses, yellow-billed storks travel in flocks, from one drying river bed to another.
When the water started to shallow, many of the fish retreated to the main river.
Those that didn't are now trapped and doomed.
The yellow-bills have a labour-saving technique for fishing in these overcrowded pools.
They just hold their beaks open and wait for a fish to blunder into them.
0nly one kind of fish is likely to survive the coming drought.
The lungfish will soon cocoon itself in the mud at the bottom, and remain there, dormant but still alive, even when the river bed is bone dry, because it can breathe air.
But before it cocoons, it has to survive another peril The shoebill stork has a massive and murderous beak.
It also has keen eyes.
And infinite patience.
0ne bite crushes the lungfish's skull.
But it still wriggles and takes quite a bit of swallowing.
0n the margins of the land, the water retreats not just once a year, but twice every day.
That exposes a completely different menu, and birds compete in order to be the first to collect it.
Here in California, there are some that take almost suicidal risks in order to do so.
The surf bird is the clear winner.
No bird gets to an edible morsel cast up by the waves quicker than it does.
It has split-second judgement.
It may also be that it gets so close to the waves because that gives it the chance of catching a barnacle or a mussel, before it has fully reacted to its exposure to the air, and closed its shell.
Where the coast is less rocky and the beaches are sandier, the waves are less violent.
Here birds of several different kinds will assemble, but they are not always in competition.
Each collects from a particular place with a particular kind of implement.
The godwits have long beaks with which to probe deeply into the sand for worms, crustaceans and little molluscs.
Dowitchers, with shorter beaks, collect the same sort of thing but from nearer the surface.
Sanderlings pick up bits and pieces that have just been washed ashore.
0ut in the shallow water, avocets are after shrimps, and other swimming creatures that don't allow themselves to get stranded on the beach.
The avocet holds its bill with the curved section just slightly parted, and as it sweeps it through the water and the mud, small invertebrates are carried into it.
The bill is so sensitive that the avocet feels when something good has arrived, and swallows it.
Fish also come into the coastal shallows, seeking the same sort of thing.
And when they do, they become the target of pelicans.
With a bill the size of a pelican's, you don't have to have pin-point accuracy.
It does help, however, for pelicans to feed in groups, for then fish fleeing from one lunging bill may blunder into another.
The brown pelican also dives.
But rather clumsily.
It's so big and buoyant, that it only goes a few feet down.
It's very often accompanied by noddy terns.
They know that the pelican has to open its bill and get rid of all that water before it can swallow any fish it might have caught.
And when it does, they might get a chance to steal part of its catch.
So now it's a question of who loses patience first.
The pelican cautiously opens its billjust slightly, and the water begins to seep from its pouch.
Done it, this time.
Boobies live on the coast, but their fishing grounds are way out in the open ocean.
Every morning they leave their roosts and set off in small parties to scour the surface of the sea.
They are searching for a pale greenish patch in the blue of the ocean that betrays the presence of a dense shoal of fish.
The fish have been driven to the surface by a shark that is still lunging into the shoal And now they are subject to an aerial bombardment.
As the boobies dive, they draw their wings half back so that they can still aim, and only fully retract them just before they hit the water.
The bombardment will continue until either the shoal manages to escape downwards, or the fading light of the evening forces the boobies to return to their roost on the coast.
Boobies don't actively swim underwater, but members of the auk family, such as these guillemots and puffins, do.
They propel themselves, not with their feet, like ducks, but with their wings, and they have paid a considerable price to be able to do so.
The wings of a booby or a gull are far too long and insufficiently robust to be beaten underwater.
So auks have had to evolve shorter, stubbier wings.
That gives them a rather clumsy, whirring flight in the air but it does enable them to fly underwater so well that they can outpace small fish.
0ne family of birds has taken this development even farther, and one of them lives herein the Galapagos.
We tend to think of penguins as sitting around on ice floes in the freezing waters of the Antarctic, so maybe these little penguins sitting right on the equator seem odd to us.
But in fact, these little ones are probably much more like the original ancestral penguin than their giant Antarctic cousins.
Because those first ancestral penguins certainly flew, as well as dived, as guillemots do today.
And if you were much bigger than this and had a wing shaped like a flipper, which is what all penguins need to swim, you would never get into the air.
So maybe these little ones are more like the first of the penguins.
Penguins underwater look somewhat like dolphins and indeed the two families have similar evolutionary histories.
Dolphins are descended from air-breathing land animals, just as penguins are descended from air-breathing flying animals.
Both subsequently took to swimming for their food.
They became beautifully adapted and streamlined.
And now, both are superlative swimmers and highly accomplished fishermen.
Some members of the penguin family can dive for 5-6 minutes without taking breath and descend to depths of a thousand feet in search of food.
Indeed, the only thing that limits penguins as swimmers, is their need to breathe air.
There is, however, one link that still ties them, and indeed all birds, to the land.
They all have to return there in order to lay their eggs.
For sea birds, the ideal place to do that is a remote island which has very few, or preferably no land-living predators.
(IMITATES BIRD CALLS) Nobody knows why it happens, but when you make strange noises here, sea birds fall from the sky.
I'm on Lord Howe Island, a tiny speck of land 300 miles off the east coast of Australia.
Human beings only got here little over 200 years ago, and it seems that the birds that nest here are still quite curious to see what's going on.
And these birds which are coming to these calls are Providence petrels.
Skilled in the air they may be, but they are certainly clumsy and ungainly on land.
When they do come down, they squabble and wrestle furiously with one another.
Perhaps they're arguing about who shall have which patch for a nest hole.
But they are still extraordinarily friendly towards human beings.
And, amazingly and very touchingly, it will stay here on my hand in a very trusting way and it gives me a chance to look at the structure at the base of its beak.
It has a tube-nose, and that structure, which it shares with a number of other ocean-going birds, is absolutely crucial to their survival out on the open ocean.
And that is where he is going to go right now.
That tube channels air to a sense organ at the base of the beak which can detect very faint odours.
That's a rare ability among birds, and it enables the tube-noses to find floating food from great distances away.
I'm at sea, 20 miles out from the east coast of Australia, and in this bucket I've got a particularly attractive liquid.
It's, eh, fish oil, it's very nutritious.
Being oil, it'll float on the surface of the sea, and above all, it smells very powerfully.
And at the moment there's not a bird in sight.
But watch what happens when I put it overboard.
The first to arrive are sooty shearwaters and Cape petrels, closely related to those Providence petrels on Lord Howe Island.
It's not only the smell of fish oil and offal to which they are sensitive.
It's recently been discovered that when small shrimps and other floating creatures feed on floating plants, algae, those plants release a gas, that in strong concentrations smells a little like rotting seaweed.
The petrels can sense even a faintest whiff of this, and so can find places where they can collect the shrimps.
Now very much bigger ocean-going birds arrive.
These magnificent birds are albatrosses.
They, too, belong to the tube-nose family, but the tube on their beaks is comparatively small.
In fact, they find their food more by sight than by smell.
They have enormous wing spans.
Two of them, the royal albatross and the wandering albatross, have the biggest wing span of any living bird.
And they circle the globe in search of food.
This is a yellow-nosed albatross.
It's not quite as big as a wanderer but it's still a very large bird, with a seven foot wing span.
No birds exploit the ocean winds with greater skill than the albatrosses.
Reading its force with peerless sensitivity, they're able to adjust their immense wings to exploit every tiny updraft deflected from the waves beneath.
So they can glide for long periods without expending any energy at all on flapping.
The wandering albatross rides the violent gales of the southern ocean, and will travel a thousand miles to bring back a cropful of food for its chick.
The chick takes nearly ten months to grow strong enough for an ocean-going life.
So although the albatross, when young, may roam the oceans for several years without touching land, eventually the need to breed brings it down to earth.
0ne bird has managed to break this long obligation to return repeatedly to land to feed its chick.
It's called the ancient murrelet, and it doesn't feed its chick on land at all.
The only place it nests are on islands around the northern rim of the Pacific, like Canada's Queen Charlotte Islands, where I am now.
And the only time you are likely to see it, is at night.
This is one of their nest holes.
The chicks, when they're only two days old, make one of the most astonishing journeys made by any chicks.
The parents come back from the sea at night and, crouching on the ground, call to their newly hatched young.
In response, the chicks come out of their holes, running.
There are large aggressive mice that will catch them if they get the chance.
Ravens and eagles are also active during these light nights.
The chicks are in real danger.
So they run, and run fast.
Their parents have gone ahead of them, and are now calling from the sea.
By midnight there are young chicks swarming all over the forest floor.
Most of them managed to get to the beach within ten minutes of leaving their holes.
But their parents are not here.
They've gone farther out, just beyond the breakers, and they're still calling.
The chicks don't stop.
They keep pedalling, like little clockwork toys, and the same movements that propelled them across the ground now take them out to sea.
In some miraculous way, each chick recognises the sound of its parents' voice.
United, the little families leave the land and its dangers and sail away into the relative safety of the open ocean.
The chicks are still only a few hours old.
The ancient murrelet must be the most truly oceanic of all birds.
Dawn, and there's not a single one of those little chicks to be seen.
By now they are all at least four miles out to sea, called there by their parents.
Sound, of course, is very important in the life of all birds.
It's the way they communicate.
And what they say, and the various ways in which they say it, is what we'll be looking at in the next programme about The Life 0f Birds.