Fishing for a Living The Life of Birds

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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 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 under this pebble I 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.

With two-thirds of the world 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.

Hot volcanic springs keep streams ice-free,

so 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 them warm.

The disadvantage of that coat of air

is that it makes its wearer very buoyant,

and a 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. They are living harpoons.

This is one of the bigger members of the family, the belted kingfisher.

The size of a small crow, it lives beside rivers and lakes all over North America.

Understandably, it prefers places where the water is clear

so it has a good view of its targets.

It must now stun the fish, which has to be head outwards.

But to swallow it without the spiny fins sticking in its throat, it must turn the fish round again.

Most kingfishers dive from perches, so they are tied to the shore.

Only 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 totally 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 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 worked out all kinds of bizarre solutions

to the problem of extracting little fish from shallow pools.

In the Florida swamps, the reddish egret performs an improbable dance.

The idea seems to be to frighten the 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 that they can't be easily seen from above.

So perhaps they deliberately shelter under the heron's wings -

which, of course, could be a mistake.

The spoonbill isn't really after fish.

This scything action enables it to gather tadpoles, beetles and 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.

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.

Or, 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 makes it snap shut.

That sounds fine,

but suppose 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 successful one.

The chicks have to be fed for six weeks.

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.

CHICK TRILLS

Ah, 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 familar birds in the world, and so perhaps we take ducks for granted.

But they are a very varied family. Different species are adapted to different ways of life on water.

Mallard, for example, are specialist dabblers.

They find all the food they need

by doing no more than dipping their heads and necks beneath the surface.

And there's lots to be found -

duckweed and tadpoles, leaves and seeds

and bits of bread thrown in by friendly humans.

If the food is really deep down, they will up-end totally.

If that doesn't get it,

then 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 all just 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.

It's the best place for a propeller and they swim 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 hatch.

But they are still covered in down and that makes swimming under water very difficult indeed,

and they use up far more energy than their streamlined parents do.

The most skilful swimmer of all freshwater birds, is the diver.

This young one has not yet got its spectacular black and white plumage.

Its feet are 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.

Diver chicks are covered with down.

That's very useful for keeping warm

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 are regularly given lifts

and, while one of their parents ferries them around, the other goes to find 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.

Lakes have a tendency to shrink.

They get shallower as rivers dump sediment and, in the tropics, may even dry up every year.

Then all sorts of delicious things come within reach, as in this African pool.

The openbill stork has a special liking for mussels

and a special way of opening them.

A sharp squeeze to make the shell open slightly,

then the lower mandible is slipped in to cut the body 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 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 fish withdrew to the main river.

Those that didn't are now doomed.

The yellow-bills have a labour-saving technique

for fishing in these overcrowded pools -

they open their beaks and wait for a fish to blunder into them.

Only one kind of fish is likely to survive the coming drought.

The lungfish will soon cocoon itself in the mud

and remain there, dormant but 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.

One bite crushes the lungfish's skull.

But it still wriggles - and takes quite a bit of swallowing.

On 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 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 judgment.

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, the waves are less violent.

Here birds of several 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 molluscs.

Dowitchers, with shorter beaks, collect much the same sort of thing

but from nearer the surface.

Sanderlings pick up bits and pieces that have just been washed ashore.

In the shallow water, avocets are after shrimps and other creatures

that don't allow themselves to get stranded on the beach.

The avocet holds its bill just slightly parted

and, as it sweeps it through the water and the mud,

small invertebrates are carried into it.

The avocet can feel when something good has arrived

and can quickly swallow it.

Fish come into the shallows for the same reason.

And when they do, THEY become the target of pelicans.

With a bill the size of a pelican's you don't need pin-point accuracy.

It does help, however, to feed in groups.

Fish fleeing from one lunging bill

may blunder into another.

The brown pelican also dives.

But rather clumsily.

It is so big and buoyant that it only goes a few feet down.

Noddy terns often accompany it.

They know the pelican will have to open its bill to empty the water

before it can swallow any fish.

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 bill just 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

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 go on until 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 with their wings

and they have paid a considerable price to be able to do so.

The wings of a booby or gull are too long and insufficiently robust to be beaten underwater.

So auks have had to evolve shorter, stubbier wings.

It gives them a rather clumsy flight

but it does enable them to "fly" underwater so well

that they can outpace small fish.

One family of birds has taken this development even farther

and one of them lives here in 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 right on the equator seem odd to us.

But these are probably much more like the original ancestral penguin than their giant Antarctic cousins.

Because those ancestral penguins certainly flew as well as dived.

And if you were much bigger, with a wing shaped like a flipper,

which all penguins use 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, penguins from air-breathing flying animals.

Both took to swimming for their food,

becoming beautifully adapted and streamlined.

And now both are superlative swimmers and highly accomplished fishermen.

Some members of the penguin family can dive for five or six minutes without taking breath

and descend to depths of 1,000 feet in search of food.

Indeed, the only thing that limits penguins as swimmers is their need to breathe air.

But there is one link that still ties them - and 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.

BIRD CALLS

HE CALLS AGAIN

BIRD REPLIES

Nobody knows why it happens,

but when you make strange noises here, sea birds fall from the sky.

I am on Lord Howe Island, a tiny speck of land 300 miles off the east coast of Australia.

Human beings only got here about 200 years ago

and the birds that nest here still seem curious to see what is going on.

And these birds which are coming to these calls

are Providence petrels.

BIRDS SHRIEK

Skilled in the air they may be,

but they are certainly clumsy and ungainly on land.

And when they do come down, they squabble and wrestle furiously with one another.

Perhaps they are arguing about which patch to have 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.

It gives me a chance to look at this structure at the base of his beak.

He has a tube-nose

and that structure, which he 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, 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 have got a particularly attractive liquid.

HE SNIFFS

It's fish oil, it's very nutritious.

Being oil, it will float on the sea

and, above all, it smells very powerfully.

At the moment, there's not a bird in sight.

But watch what happens when I put it overboard.

BIRD CALLS

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're sensitive.

It's been discovered that when small shrimps and other floating creatures feed on floating plants,

those plants release a gas that smells a little like rotting seaweed.

The petrels can sense even the faintest whiff of this

and so can find places to collect the shrimps.

Now, very much bigger ocean-going birds arrive.

BIRDS CLUCK AND CAW

These magnificent birds are albatrosses.

They too are members of the tube-nose family, but the tube on their beaks is comparatively small

and in fact THEY find their food more by sight than by smell.

But they have enormous wingspans.

The royal albatross and the wandering albatross have the biggest wingspan of any living bird.

And they circle the globe in search of food.

This is a yellow-nosed albatross.

It is not quite as big as a wanderer but it is still a very large bird with a seven-foot wingspan.

No bird exploits the ocean winds with greater skill than an albatross.

Reading its force with peerless sensitivity,

they are able to adjust their immense wings

to exploit every tiny updraught 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.

SHRILL CRIES

CHICK CRIES AGAIN

It takes 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.

One bird has managed to break this long obligation

to return repeatedly to land to feed its chick.

It is called the ancient murrelet

and it doesn't feed its chick on land at all.

It only nests on islands around the northern rim of the Pacific,

like Canada's Queen Charlotte Islands, where I am now.

And you're only likely to see it at night.

This is one of their nest holes.

The chicks, when they are only two DAYS old, make one of the most amazing journeys made by any chicks.

The parents come back from the sea at night and, crouching, call to their newly hatched young.

The chicks come out of their holes running.

Large, aggressive mice 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 fast.

Their parents have gone ahead and are now calling from the sea.

By midnight, there are young chicks swarming all over the forest floor.

Most of them manage to get to the beach within ten minutes of leaving their holes.

But their parents are not here.

They have gone farther out

and they're still calling.

The chicks don't stop. They pedal on, like little clockwork toys

and the movements that propelled them across the ground now take them out to sea.

In some miraculous way,

each chick recognises the sound of its parent's voice.

United, the little families leave the land and its dangers

and sail 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 is not a single little chick to be seen.

By now they are all at least four miles out to sea, called there by their parents.

Sound, of course, is important in the life of ALL birds. It's how they communicate.

And what they say, and the various ways in which they say it,

is what we will look at in the next programme about the life of birds.

Subtitles by Mairi Macleod BBC Scotland - 1998