Finding Partners The Life of Birds

This lava gull in the Galapagos,

like all the rest of those birds, it is sending a very clear message.

It's saying, "I'm ready to mate and I've got a great place for a nest."

Their visual signal is normally an inconspicuous patch of shrivelled skin on the throat.

It takes about 20 minutes to blow one up.

The females, who don't have a throat pouch, cruise by, assessing what is on offer.

The size of the balloon gives an indication of a male's vigour and thus his desirability as a father.

The female leaves

and one of the homeless males decides to make a challenge.

The throat pouch is an obvious target -

tear that and its owner can't attract anyone.

A new proprietor takes over the nest site and pumps up HIS balloon.

Success is swift.

She's found what she was looking for.

he cements their relationship with a few judicious gifts.

A little fruit.

Males worldwide ingratiate themselves with females in this way.

Wattled guans do in the tropics of Amazonia.

And so do great tits in the suburban gardens of Europe.

Sea birds, of course, like fish,

though it's still the prerogative of the female to decline a gift the first time it's offered.

Grebes like fish too - these are on a lake in North America.

But for grebes in particular,

Once they've got to know each other really well, however,

they perform their pas-de-deux

with immaculate timing.

but the dancers make up for that with impressive footwork.

After the dancing,

A male swallow-tailed gull also declares his intentions

with a down payment on the nest.

As a pair get to know one another better,

they become sufficiently trustful to indulge in mutual preening.

Albatross behave in the same way.

These bills are quite strong enough to injure anything or anyone that dares to interfere with them,

but now, as the pair sit together on their nest site, they are used to deliver the most tender of caresses.

What follows may seem like duelling,

but actually, it is, once again, a kind of dancing.

The sequence of movements

is long and complicated.

If both partners perform without mistakes and in harmony,

So pairs are formed,

and the union is consummated.

For most birds, the pair will stay together for several weeks, if not for years.

These waved albatross in the Galapagos will stay together for the rest of their lives,

and that is very unusual.

Insects don't stay together, frogs and toads don't, lizards and snakes don't. Why should birds?

The answer is there.

No female bird can manage to fly around with an egg inside her, let alone several,

for the days or weeks it needs to develop.

The evidence doesn't support that.

It's not so much the mutual affection

as the concern it has for its own genes which are in the egg.

If, without jeopardising those,

either bird could find a way of spreading its genes more widely,

the evidence suggests

they would take it.

Here in Jamaica,

some male birds are far from faithful.

Flame trees, when in flower, produce delicious, sweet nectar.

It is the staple diet for hummingbirds

and Jamaica has many different species of them.

The male streamer-tailed hummer is a vigorous and aggressive creature

and a strong individual will take control of an entire tree.

for everyone.

But he's not fighting just because he wants to drink all the nectar.

He is more devious than that.

The tree is the most prolific source of nectar around.

There are female streamer-tails in the neighbourhood,

and they're busy building nests.

They're relatively plain creatures, lacking the long streamer-like tails of the male.

There's so much nectar that they'll be able to feed their chicks alone.

He erects little tufts like ears on either side of his head.

She accepts him.

He goes back to wait for the next diner...

..while she pulls herself together and prepares for life as a single parent.

A good, secure home can also be a very effective lure

with which to attract a female.

Red-headed weavers nest in colonies,

and the yellow-headed females keep an eye on what they are building

before committing themselves.

A lot of work goes into each nest.

It's important the weaves be tight - too loose and the eggs might drop through.

When one is finished and ready for judging,

the male perches hopefully beside it.

She clearly doesn't think much of this one.

This, however, is good enough to warrant an internal inspection.

each of which holds chicks he has fathered.

Each female, by choosing him as a mate,

has provided her young with the best genes available,

and he has quadrupled the number of his offspring.

But some birds construct even bigger buildings to impress females,

and to see the most spectacular you have to come to the forests of the islands north of Australia.

Some females can be persuaded to mate for rewards that are more abstract than mere food and lodging.

There's a kind of bird here in New Guinea whose females select a male not for a meal ticket,

He has a passion for interior decoration.

His hut - almost big enough for me - is neither a home nor a nursery.

It's a gallery for displaying his artistic creations

to visiting females.

These flowers come from a creeper that's only just started to bloom - great if you like colour.

And he loves it!

The iridescent wing-cases of beetles

also appeal to him and he has amassed an impressive collection.

But they're always in need of rearrangement to show them off

with a slightly different artistic sense.

If a female decides these are the best jewels, then she'll mate with the owner.

So here, where living is easy,

a female is not bowled over by food or accommodation, but by beauty.

And beauty can be found not only in jewels, but in costumes.

This is Bulwer's pheasant,

and he has got spectacular wattles.

He's impressive enough normally,

but when she is around he gets very excited indeed!

Impressive though he is, she is very critical.

He's not good enough, it seems.

Another pheasant - Temminck's tragopan.

His costume jewellery is even more elaborate.

And if you've got it, why not flaunt it?

than is possessed by any other bird.

The argus pheasant has the largest of all tail feathers,

and wing feathers that are certainly as spectacular.

And what can rival the train of a peacock?

The costume put on specially for courtship dances by the African widowbird

It's hazardous exposing yourself like this, even if you can fly.

You're making yourself an easy target for a hawk and there are many around here in Kenya.

Evidently the matings a male gets from displaying in this fashion

make the risk worthwhile.

Up in the frozen north, on the Arctic tundra,

life is too rigorous to allow such extravagance.

Here, males display in a more modest way.

The buff-breasted sandpiper - no spectacular plumes for him.

Flashes like these can be seen a good 200 yards away.

A female has got the message.

She's definitely interested.

Now there are three females.

It's time to reveal all!

He reinforces his appeal with quiet clicking calls.

Now there are four females with male number one. This hardly seems fair.

Number two's wings don't appeal!

So he comes over to where the action is.

The females don't know which way to turn.

But number one won't allow anyone else on his pitch for long.

There's not room on this part of the tundra for two.

only too often leads to physical violence.

Scotland.

Here in the pine forests of the Highlands, fights between males are among the most violent of all.

The capercaillie is the biggest of grouse.

The arenas where the males display

are vigorously contested, and the best, in the end,

is claimed by the most powerful male who will defend it against anyone.

But here's a really serious rival.

He is being very reckless indeed.

Birds can get very badly injured in battles like these, and even die from their wounds.

But the rewards they're fighting for are very great.

This is the most important moment of their year.

And they seem to agree on who the champion is.

Runners-up are almost always rejected,

while the winner attracts almost more mates than he can deal with.

Some males make the job of the females in choosing them easier

by gathering together and displaying in groups.

And there's one bird in the Brazilian rainforest

who has the oddest way of impressing a female.

It's called the calf bird.

They compete with calls.

The sound is greatly amplified by air sacs on their throats.

This assembly is 100 feet above the ground, high in the canopy,

so high that very few people have seen the birds performing this incredible chorus, let alone film it.

The females look exactly the same as the males - as you might expect as costumes aren't used to compete.

When a female flies down to the best branch,

all the males call with renewed intensity.

More females arrive.

She tells the male she has chosen him by giving him a peck on the neck.

That's the idea!

And then he notices a second female.

Call as they might,

none of the other males get a look in.

The calf bird has a cousin whose males also display in groups. They compete not with sound, but colour.

The cock-of-the-rock.

The males assemble in groups of a dozen or so,

perching low down on lianas, watching out for females

The female is dull-coloured. She has no use for bright feathers.

Her arrival at the display ground has an immediate effect.

The males flop down.

Each one owns a particular patch of ground - his court -

on which he, and he alone, displays.

Each now has the problem of how to persuade her to land beside him,

and a cock-of-the-rock's idea for doing that is to bounce... competitively.

Once again, a peck on the neck says, "I'm yours".

And, once again, the male is not very quick on the uptake.

But he gets there eventually.

After this is over, she will go off and rear her chicks by herself.

Another female.

She makes exactly the same selection.

By gathering together, the males make sure that the females know where the marriage market is,

but the price of doing so

is that only one or two males will make a sale.

He is captain of this team and he whistles to summon other members.

The team is complete

and the show begins.

They want to prove that they are the best team of acrobats in the area.

A female arrives to get a close-up view of the performance from the actual dancing perch.

If she is sufficiently impressed,

she will mate with the captain.

But why should he be helped? Because if something happens to the captain,

one of them might inherit his title. Maybe not a large chance,

but it's better than performing solo and having no chance at all.

If the lady decides to accept him, she will mate with him nearby.

She will fly away and he will keep on dancing, hoping for more success.

He will never knowingly see his offspring.

But not all polygamous birds are so neglectful of their duties.

Here on the pampas of Argentina

lives another male with many wives

who takes his nursery duties very seriously indeed.

These eggs are all looked after by one single male,

and even now

he is trying to entice another female to come here to add to this huge clutch.

He settles down to continue incubating.

And one of the females with whom he mated yesterday is now ready to lay.

She settles down within a yard or so of the nest.

An egg is on its way.

Because the male has taken total charge of the nest, the females can be just as promiscuous as he is.

And that female having laid here, will now be going away to find another male with another nest

to see if he'll accept another egg.

That's unusual behaviour for a male -

taking total responsibility for incubation and chick rearing.

On the tundra of the Arctic, however,

another species has taken this reversal of roles further still.

These are red phalaropes.

that's typical male behaviour.

But the truth becomes apparent when you see them mating.

It's the duller one who mounts on the other's back who is the male.

THAT is the female.

HE now goes back to the nest that HE has already built.

The brighter coloured female comes back to him several days thereafter

to mate again and add more eggs to the nest.

While SHE sits, HE stands aside.

But mating openly with multiple partners is the exception.

In most species, both parents are needed to bring up the young,

so most birds remain as a pair at least during the breeding season.

An indication that this is the basis of their relationship is that the sexes are broadly similar.

But even so, living as a pair doesn't preclude

a little infidelity now and then.

Perhaps the most bizarre behaviour of all takes place in the gardens of England -

and it seems that until recently, nobody even noticed.

A young female hedge sparrow, a dunnock, ready to lay.

The pair often feed together -

a devoted couple if ever you saw one.

He seldom lets her out of his sight

for she is not as faithful as she might be.

There's a third bird around, Beta,

another, younger male.

He's not popular with Alpha and they're continually squabbling.

Sometimes the fights can get quite vicious and feathers fly.

But, in spite of that, Beta stays around,

calling quietly to her.

She joins him

and now, while Alpha is preoccupied with feeding,

she and Beta get together.

Twirling her tail invitingly, in a split second they mate.

Beta flies away.

But now, out in the open,

she is courting Alpha with that same old tail twirling.

He takes precautions to ensure his paternity.

He pecks her genital opening...

And now he mates with her,

and it will be his sperm that will fertilise her eggs.

She has kept two males happy, who will help feed the young when they hatch.

Alpha has made sure that he will be the father of the eggs she will lay,

or, at any rate, most of them.

But it's here in the southeast woodlands of Australia

that infidelity reaches its most astounding, indeed you might say, its ultimate height.

And it occurs among the families of this dazzling little bird -

the superb fairy wren.

He is an attentive male, courting his female with little gifts of food.

One of them dances for her, flaring the blue fans on his cheeks.

Yet another male is also flirting with her.

And here's another.

And she selects one of them.

But her first established male is not around to see all this.

He is visiting a female neighbour, and he's carrying a bouquet,

pays off too.

Now he's back at his own nest with his first mate,

looking after the chicks the nest now contains.

So the female fairy wren chooses the flashiest males to father her chicks,

and allows her partner only just enough matings to ensure he helps to feed the family.

And while the males may have chicks in as many as six nests,

they may not have a single one in the nest they tend.

They say it's a wise child that knows its own father, but that's never truer than in the bird world.

But extreme infidelity, like polygamy, is not widespread among birds.

Males and females conduct their courtship on equal terms,

and when they are convinced they are compatible

they work together to build a nest.

Protected by water, and with a strong mate to see off intruders,

these swans will probably hatch their egg successfully. But for many,

they are entering the most difficult part of their lives.

They will have to be extremely ingenious to raise a family,

as we'll see in the next programme in The Life Of Birds.

Subtitles by BBC - 1998