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00:01:13,407 --> 00:01:16,001
An Indian florican. He's got a problem.

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00:01:16,167 --> 00:01:18,556
He wants to attract females and mate,

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but in tall grass it's not easy
to tell them where he is.

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He's so anxious to impress females
with his strength and fitness as a mate

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that he may do this 400 times a day.

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There are, of course,
other ways of broadcasting such messages

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00:02:11,487 --> 00:02:13,603
in places where it's difficult to be seen.

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00:02:22,887 --> 00:02:26,277
A nightingale in an English woodland in spring.

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He's recently arrived
from his winter quarters in Africa.

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(SINGS)

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He continues singing into the night,

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perhaps because the females who arrive after him

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usually travel under cover of darkness
and may be passing overhead.

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Whales sing, too.

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The song of the female right whale
travels great distances through the water

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and can be heard by other whales
at least five miles away.

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Her calls also announce that she's ready to mate,

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and the males who have gathered around her
push and butt one another to get alongside her.

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The act of coupling lasts only a few seconds,

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so the males have to be ready
to seize the chance.

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Teasingly, she rolls over,

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preventing the jostling males
from mating with her just yet.

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She is encouraging competition
between her suitors.

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Males who are bigger and stronger
will push rivals out of the way

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to lie beside her and mate when she allows it.

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That way she achieves
the objective of her courtship -

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to secure the best father for her calf.

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0n the open grasslands
of central Asia, the steppes,

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lives an animal that issues invitations
to prospective partners with a perfume.

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The dwarf Siberian hamster.

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This little female is about to give birth,

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but before she does
there is something else she must do.

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She marks the vegetation around her burrow
with a secretion from beneath her tail.

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As the day begins to dawn,
she retires below ground to her nest chamber

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and there gives birth.

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Her half-dozen babies are still
very underdeveloped, naked and blind,

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for they've only spent 28 days in her womb.

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But she's unlikely to live for much longer
than a year, and she has no time to waste.

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Now she must supply her babies with some milk.

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But because this may be
her only breeding season,

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she's also in a great hurry to mate again.

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and supplying them with milk.

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The effectiveness of that message of perfume
that she posted up last night is now crucial.

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The wind has spread it all over the steppes,

45
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and males within half a mile
in any direction will have detected it.

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Here they come, full of excitement.

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So once again she couples.

48
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But hamster mating is quite a long business.

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0ne copulation is not enough.

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The male follows her down into her burrow
to make sure none of his rivals outside

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manages to displace him.

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An hour or so later, he's still with her.

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The other males have missed their chance.

54
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While all this has been going on during the night,

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other hamsters have been wandering around,

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seemingly unaffected by all this excitement.

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But why should this little male, within two or
three feet of that female's perfumed message,

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ignore it when that same message
will bring another male from half a mile away?

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The fact is that this male, although he looks
very like the female, is a different species.

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He feeds mainly on insects,
she on seeds and grass.

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Her message contained two statements:

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not only, ''Hurry, I want a mate,''
but also, ''This is who I am.''

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And this little male knew
that she was not for him.

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00:08:14,287 --> 00:08:18,360
And that second part of the message
is very important.

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It prevents animals from trying to achieve
matings that can never be successful.

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The more crowded the environment,
the plainer these statements must be.

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The coral reef has the densest and most varied
population of fish of any part of the sea.

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Butterfly and angel fish
are among the commonest.

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There are many closely related species,
all with very similar-shaped bodies -

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roughly rectangular.

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But the colour patterns on these rectangles
are as varied as the designs on national flags.

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With such clear declarations of identity
emblazoned on their bodies,

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no one is likely to court an unsuitable partner.

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When courtship begins,

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individuals must make sure that their
identity badges are prominently displayed.

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Boobies are ocean-going birds,
common throughout the tropics.

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There are half a dozen species of them.

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Since several kinds may nest on the same island,
there could be some confusion.

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But this is a blue-footed booby,

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and when a male starts to court a female,

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he leaves her in no doubt about that.

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(H0NKING CALLS)

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Bluefoots don't make a proper nest,
just a scrape,

84
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but a relic of this nest-making urge
remains in their courtship.

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How better to indicate your willingness to mate
than with a little token nest material

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deposited on your partner's attractive blue feet?

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The bluefoot's identity badge is permanent -
its feet are blue throughout the year -

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but other birds only wear their badges
during the breeding season.

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Male ducks - this is a wood duck -
grow new feathers each spring.

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00:11:02,807 --> 00:11:06,516
During the winter they,
like their females, were a plain brown.

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00:11:06,687 --> 00:11:10,282
A male merganser. His female is also drab.

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The female ducks incubate
the eggs by themselves,

93
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and a sitting duck needs camouflage.

94
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The males reinforce their costumes with displays.

95
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The smew bobs his head
and his female responds invitingly

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by vibrating her tail
and swimming low in the water.

97
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The golden-eye favours
a rather more restrained head-bob,

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but that is all his female needs to be convinced
that he is the right partner for her.

99
00:11:55,047 --> 00:11:59,325
But how does a duck know
what its appropriate mate should look like?

100
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Females know innately,
but the males have to learn.

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The first moving thing ducklings normally see

102
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as they emerge from the shell is their mother.

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This image becomes imprinted
in the brain of the ducklings,

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and for the next few weeks
they will follow it unwaveringly.

105
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The male duckling never forgets
the appearance of his mother,

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and when a little mallard starts looking
for a mate, it's her that he seeks to match.

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But this male duckling is not a mallard.
He's a young golden-eye.

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He hatched from an abandoned egg
given to a mallard foster mother.

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Though he looks different from the mallards,

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he's completely accepted into her family
and he follows her wherever she goes.

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Next year, if he survives,

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he will be in the same predicament
as this adult golden-eye.

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He, too, was brought up
by a mallard foster mother.

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The female golden-eye, impressed by his
plumage, makes the right signals of acceptance.

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Another joins her.

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He ignores them both.
They're not what he's seeking.

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His displays are directed to a female
like his foster mother, a female mallard,

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and she, alas, finds his signals
totally incomprehensible.

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But being the right species
is not necessarily enough.

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An individual male may have to have
some extra attraction to offer.

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This tree stump, here in the forests
of Central America, contains a pool of water,

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and that's just what a female damselfly needs,
because she can only lay her eggs in water.

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So any male that can claim this
and drive off rivals

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really has something to offer.

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This is the biggest of all damselflies,

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and the distinctive flight with which
the male proclaims his ownership of a pool

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has given it the name of helicopter damselfly.

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Rival males are chased away.

129
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But a female will be attracted
by his display and lay eggs in his pond.

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He remains on guard after she's gone
and will readily welcome other females,

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so that eventually his precious pond,
if it's large enough, may contain several larvae.

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He is father of them all.

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0ther male insects offer
other enticements to their females.

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Hanging flies in North America. They are hunters.

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Flies are their favourite food, if they can get them.

136
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But beetles may have to do.

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00:15:11,087 --> 00:15:14,443
This male has caught a fly,
but he doesn't eat it all.

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00:15:14,607 --> 00:15:17,201
He uses it as a bait for a female.

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To advertise it, he fans his wings
and disperses a perfume

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released from the tip of his abdomen.

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00:15:24,367 --> 00:15:26,756
A female approaches.

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00:15:33,447 --> 00:15:37,565
Had this been a small fly or a beetle,
she wouldn't have stayed,

143
00:15:37,727 --> 00:15:44,121
but she approves of this large, juicy one and,
as she feasts on it, she allows the male to mate.

144
00:15:51,407 --> 00:15:53,443
But he won't let go of his gift.

145
00:15:53,607 --> 00:15:57,282
Transferring sperm for a hanging fly
is a lengthy business,

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and it may take him 20 minutes to complete it.

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He grips her securely
while she continues to feed.

148
00:16:06,007 --> 00:16:08,396
Mating completed, he releases her.

149
00:16:08,567 --> 00:16:12,765
She wants to take the remains of the fly
with her, but he wants to keep it,

150
00:16:12,927 --> 00:16:15,316
and a wrestling match starts.

151
00:16:20,567 --> 00:16:25,357
He wins. Even a second-hand meal
may attract another female.

152
00:16:32,567 --> 00:16:36,355
And within a minute or so,
another female is interested.

153
00:16:40,047 --> 00:16:43,278
Aerobatic skills are what impress tropic birds.

154
00:16:43,447 --> 00:16:47,520
Both male and female will have to
catch food at sea for their nesting,

155
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and when adults select partners,
both sexes assess each other's merits

156
00:16:51,687 --> 00:16:54,076
as a likely future parent.

157
00:17:00,607 --> 00:17:04,805
At the beginning of the season,
large groups display together.

158
00:17:07,007 --> 00:17:10,477
Soon the birds pair off
and then, for minutes on end,

159
00:17:10,647 --> 00:17:14,925
again and again, they perform
the most elegant pas de deux.

160
00:17:29,927 --> 00:17:33,158
A marsh harrier, seeking to impress his mate,

161
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provides absolute proof
of his prowess as a hunter.

162
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She takes his catch from him in mid-air.

163
00:17:47,607 --> 00:17:53,557
He gives an exhibition of slow-speed flying,
with legs lowered, over a likely nest site.

164
00:18:07,567 --> 00:18:10,081
The female alone will construct the nest,

165
00:18:10,247 --> 00:18:16,641
but he will collect a great deal of the building
material, and he demonstrates his ability to do so.

166
00:18:25,767 --> 00:18:31,717
The pair also display by clasping as they fly
not only building material and prey,

167
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but one another.

168
00:18:40,047 --> 00:18:45,041
He will continue to feed her in this way
throughout the nesting period.

169
00:18:57,327 --> 00:19:01,445
Termites. The favourite food
of the red-backed salamander.

170
00:19:10,087 --> 00:19:15,844
This male has a territory that contains lots of
termites, and his droppings provide the evidence.

171
00:19:16,007 --> 00:19:19,602
They are smooth and even compared with these,

172
00:19:19,767 --> 00:19:23,157
deposited by a salamander
who's been feeding on ants.

173
00:19:24,927 --> 00:19:26,918
Ants are not nice to eat.

174
00:19:27,087 --> 00:19:29,885
They have indigestible
horny coverings to their bodies

175
00:19:30,047 --> 00:19:33,835
and stings loaded with formic acid -
not nice at all.

176
00:19:34,007 --> 00:19:39,400
But if that's all there is in your territory,
well, they're better than nothing.

177
00:19:48,247 --> 00:19:50,238
A female looking for a mate.

178
00:19:50,407 --> 00:19:57,119
She wants a male with a territory rich in termites,
where her young can get a good start in life.

179
00:19:57,287 --> 00:20:00,040
This place is clearly no good.

180
00:20:05,207 --> 00:20:08,199
This, on the other hand, might be better.

181
00:20:17,487 --> 00:20:19,876
She makes quite sure.

182
00:20:23,407 --> 00:20:29,801
Having convinced herself of the quality of this
male's territory, she traces him to his burrow.

183
00:20:38,967 --> 00:20:42,277
Here she will mate and leave her eggs.

184
00:20:45,407 --> 00:20:51,039
Moose, in the rutting season,
also develop a fixation on excrement.

185
00:20:51,207 --> 00:20:55,644
A bull moose establishes a territory
in areas favoured by females.

186
00:21:09,527 --> 00:21:11,916
0ther males have to be kept away.

187
00:21:23,527 --> 00:21:28,078
The male has a special way
of encouraging females to mate with him.

188
00:21:28,247 --> 00:21:31,603
Every day, he urinates in special pits.

189
00:21:39,687 --> 00:21:43,839
His urine has a smell that the females find
both pleasurable and exciting.

190
00:21:44,007 --> 00:21:47,079
That brings them into sexual receptivity.

191
00:22:11,287 --> 00:22:16,281
They wallow in the pits,
drenching themselves in his perfume.

192
00:22:18,087 --> 00:22:20,476
All of the females in the group want a turn,

193
00:22:20,647 --> 00:22:25,004
but the one in occupation
is frequently very possessive.

194
00:22:27,287 --> 00:22:32,236
Perfume is also used by this bat
to attract and keep a harem.

195
00:22:32,407 --> 00:22:34,796
He is a sac-winged bat in Trinidad

196
00:22:34,967 --> 00:22:40,166
and he establishes a roost for his females
on the side of a silk cotton tree.

197
00:22:41,287 --> 00:22:43,676
When a female returns at dawn,

198
00:22:43,847 --> 00:22:48,841
he stretches out his wing
to expose a perfumed gland on his elbow.

199
00:22:49,927 --> 00:22:52,839
The females find this smell highly attractive.

200
00:22:53,927 --> 00:22:56,316
He wafts his scent towards them...

201
00:23:00,247 --> 00:23:04,684
..and then hovers in front of the female
so that his perfume surrounds her,

202
00:23:04,847 --> 00:23:09,079
a perfume that stimulates her
and binds her to him socially.

203
00:23:19,287 --> 00:23:23,883
These bright flashes and calls
are made by another bat.

204
00:23:26,087 --> 00:23:28,078
(CHIRPING CALL)

205
00:23:30,687 --> 00:23:33,724
A male epauletted bat.

206
00:23:33,887 --> 00:23:38,039
The females of this species
assess these invitations with care.

207
00:23:38,207 --> 00:23:42,439
Their relationship with a male will be
no more than a visit of a few seconds

208
00:23:42,607 --> 00:23:46,361
during which they mate,
but which male is it to be?

209
00:23:46,527 --> 00:23:49,485
The males have no extra inducements on offer,

210
00:23:49,647 --> 00:23:54,038
such as rich territories,
nest-making skills or even bribes of food,

211
00:23:54,207 --> 00:23:58,200
only their qualities as a father
for the female's baby.

212
00:24:01,047 --> 00:24:04,960
The female must select
the healthiest and most attractive male

213
00:24:05,127 --> 00:24:08,756
so that her baby has a good chance
of inheriting such qualities.

214
00:24:08,927 --> 00:24:13,921
Choosing which he is to be demands
a close inspection of the candidates.

215
00:24:18,687 --> 00:24:24,876
The male supports the entreaties proclaimed
by his bristling epaulettes with energetic honks,

216
00:24:25,047 --> 00:24:28,801
but serenades can be more beguiling than his.

217
00:24:35,807 --> 00:24:38,196
(RHYTHMIC, MUSICAL CALL)

218
00:24:53,087 --> 00:24:57,478
The lyre bird of Australia produces
one of the most varied and glorious

219
00:24:57,647 --> 00:25:00,036
of all animal songs.

220
00:25:07,647 --> 00:25:11,003
Each male maintains several courts
in his territory in the bush

221
00:25:11,167 --> 00:25:13,237
on which he sings and dances.

222
00:25:13,407 --> 00:25:16,479
He tours from one to the other
and cleans them meticulously

223
00:25:16,647 --> 00:25:19,605
before he starts his performance.

224
00:25:28,327 --> 00:25:30,921
(CHIRPING S0NG)

225
00:25:43,007 --> 00:25:44,998
He's a superb mimic.

226
00:25:45,167 --> 00:25:50,195
An experienced male can sing the songs
of nearly all the other birds in his territory.

227
00:25:54,847 --> 00:25:57,725
(SQUAWKING)

228
00:25:57,887 --> 00:26:02,722
That's a very accurate imitation
of the laugh of the kookaburra.

229
00:26:19,207 --> 00:26:24,361
The males, like the male epauletted bats,
take on no parental duties.

230
00:26:24,527 --> 00:26:29,203
They leave nest-building, incubation and
feeding the young entirely to the female,

231
00:26:29,367 --> 00:26:33,758
so they're able to devote
all their time and energy to these displays.

232
00:26:39,727 --> 00:26:44,084
Females travel from one territory to another
assessing the rival males

233
00:26:44,247 --> 00:26:48,206
for the complexity of their song
and splendour of their plumes.

234
00:26:48,367 --> 00:26:52,758
A particularly successful male
may mate with many females.

235
00:26:59,087 --> 00:27:04,525
The lyre bird is unusual in having both
an elaborate song and magnificent plumes.

236
00:27:04,687 --> 00:27:07,076
Most birds invest in one or the other.

237
00:27:07,247 --> 00:27:09,920
Those that rely primarily on visual displays

238
00:27:10,087 --> 00:27:13,079
have developed the most ravishing costumes.

239
00:27:14,447 --> 00:27:16,836
The tragapan from Western China.

240
00:27:17,007 --> 00:27:20,886
He only reveals
the full beauty of the wattles on his throat

241
00:27:21,047 --> 00:27:23,436
when a female approaches.

242
00:28:25,927 --> 00:28:29,317
The Palawan peacock pheasant
from the Philippines.

243
00:28:47,167 --> 00:28:51,160
The standard-winged bird of paradise
from the Molucca Islands,

244
00:28:51,327 --> 00:28:54,319
with some of the oddest of all plumes.

245
00:29:14,887 --> 00:29:17,799
The rifle bird of Australia.

246
00:30:00,287 --> 00:30:04,758
It's this appetite of females
for increasingly dramatic spectacles

247
00:30:04,927 --> 00:30:09,523
that has forced the males to dance to their tune
in ever more extreme ways.

248
00:30:09,687 --> 00:30:14,477
And surely the most spectacular of all
is the display of the peacock.

249
00:30:34,727 --> 00:30:37,560
Elaborate plumes are something of a handicap.

250
00:30:37,727 --> 00:30:40,195
They make it more difficult for the bird to fly

251
00:30:40,367 --> 00:30:44,121
and they also make it
more conspicuous for any predator to find.

252
00:30:44,287 --> 00:30:49,315
So it's not surprising that most birds,
at the end of the breeding season, shed them.

253
00:30:49,487 --> 00:30:51,682
But that is a considerable waste.

254
00:30:51,847 --> 00:30:56,363
0ne family of birds, the bowerbirds,
have found a very ingenious way

255
00:30:56,527 --> 00:30:59,246
of avoiding these two disadvantages.

256
00:30:59,407 --> 00:31:01,443
This is not a nest.

257
00:31:01,607 --> 00:31:04,997
It's a display case built by the male bowerbird

258
00:31:05,167 --> 00:31:09,797
in order to show off the objects
he collects to impress the female.

259
00:31:09,967 --> 00:31:13,846
He gathers together flowers,
feathers from other birds,

260
00:31:14,007 --> 00:31:16,885
anything as long as it's brightly coloured.

261
00:31:17,047 --> 00:31:20,960
The satin bowerbird that built this bower
prefers blue objects.

262
00:31:21,127 --> 00:31:25,120
He's fussy not only about their colour
but their arrangement.

263
00:31:25,287 --> 00:31:29,519
So if I take this blue parrot feather
and put it just there,

264
00:31:29,687 --> 00:31:32,042
he won't like it at all.

265
00:32:01,287 --> 00:32:06,077
The male alone is responsible
for building these showcases.

266
00:32:08,087 --> 00:32:12,877
Females regularly tour the bowers,
assessing their riches.

267
00:32:14,047 --> 00:32:18,916
The arrival of one
stimulates the male to posture and strut.

268
00:32:20,047 --> 00:32:25,644
But she's not yet made up her mind. There may
be a more impressive bower elsewhere.

269
00:32:27,727 --> 00:32:30,719
A rival and more dominant male appears.

270
00:32:35,287 --> 00:32:39,883
He steals the treasures
while the proprietor of the bower is away.

271
00:32:57,447 --> 00:33:01,838
He does more. He's not only a thief but a vandal.

272
00:33:25,847 --> 00:33:30,637
And he uses the remains
of the demolished bower to reinforce his own.

273
00:33:32,687 --> 00:33:38,683
He now has the most spectacular collection
of decorations in the whole neighbourhood.

274
00:33:43,767 --> 00:33:47,840
And this individual embellishes
his treasury in yet another way.

275
00:33:48,007 --> 00:33:52,205
He paints its walls with a blue paste
made from mashed berries.

276
00:33:52,367 --> 00:33:55,165
It's all done to impress the female.

277
00:34:07,887 --> 00:34:14,884
If she is going to mate, it will be here between
the walls of the bower that she will receive him.

278
00:34:31,287 --> 00:34:34,085
There are 18 different species of bowerbird,

279
00:34:34,247 --> 00:34:39,685
each with its own architectural design
for a bower and its own taste in ornaments.

280
00:34:39,847 --> 00:34:42,839
This is the bower of the golden bowerbird.

281
00:34:43,007 --> 00:34:45,999
Up here in the forests, which are rather wetter,

282
00:34:46,167 --> 00:34:50,797
there's a kind of fungus which grows on twigs
binding them together.

283
00:34:50,967 --> 00:34:54,516
So this bower is a much more solid structure

284
00:34:54,687 --> 00:34:57,759
and much less easily destroyed
than that of the satin.

285
00:34:57,927 --> 00:35:02,443
Indeed, this particular bower
may be as much as 40 or 50 years old.

286
00:35:02,607 --> 00:35:04,996
This is the perch on which the bird displays.

287
00:35:05,167 --> 00:35:09,604
And here are its treasures,
which are not blue, but pale green,

288
00:35:09,767 --> 00:35:12,406
with white flowers with black seeds in them.

289
00:35:12,567 --> 00:35:15,639
And there's one further difference
with the satin bird.

290
00:35:15,807 --> 00:35:18,640
The golden bowerbird is a much shyer creature.

291
00:35:18,807 --> 00:35:23,881
If I'm going to be lucky enough to see it,
I'm going to have to retreat some distance.

292
00:35:32,887 --> 00:35:35,685
He's got another of those white flowers.

293
00:35:48,247 --> 00:35:51,205
A female having a critical look.

294
00:36:15,767 --> 00:36:19,680
The male sneaks onto a neighbouring bower
while the owner is away.

295
00:36:19,847 --> 00:36:24,682
The tower of twigs may be a fixture,
but the treasures can be filched.

296
00:36:36,527 --> 00:36:41,078
The rivalry between black grouse
is rather more obvious.

297
00:36:41,247 --> 00:36:43,363
The males, here displaying in Scotland,

298
00:36:43,527 --> 00:36:47,406
have their dancing courts
alongside one another on the open moors.

299
00:36:47,567 --> 00:36:50,718
Such closeness inevitably leads to quarrels.

300
00:36:50,887 --> 00:36:53,276
(C00ING)

301
00:37:11,727 --> 00:37:14,639
Such an arrangement, however,
allows the females

302
00:37:14,807 --> 00:37:19,198
to make their assessments and comparisons
much more easily.

303
00:37:53,487 --> 00:37:58,277
Their decision seems to be based
not only on the splendour of the males' displays

304
00:37:58,447 --> 00:38:01,962
and the vigour of their dances,
but also where they dance.

305
00:38:02,127 --> 00:38:06,120
The females prefer to mate
in the centre of the whole gathering,

306
00:38:06,287 --> 00:38:10,280
and the male who has battled for and won that
will get the majority of females.

307
00:38:23,887 --> 00:38:28,119
You might think that such mass displays
would be impossible

308
00:38:28,287 --> 00:38:31,324
in such thick undergrowth as this in Trinidad,

309
00:38:31,487 --> 00:38:34,047
but that's exactly what's going on here.

310
00:38:34,207 --> 00:38:38,758
These little black and white birds
are mannequins.

311
00:38:38,927 --> 00:38:45,446
Each male has industriously cleared
for himself a little dancing court.

312
00:38:45,607 --> 00:38:48,724
What's more,
they're all so obsessed with dancing

313
00:38:48,887 --> 00:38:53,881
that they don't just do so for a few weeks
in the year but for nine whole months,

314
00:38:54,047 --> 00:38:58,837
and, what is more,
for 90% of daylight hours within those months.

315
00:39:01,447 --> 00:39:06,123
The males keep their courts
meticulously clean and tidy.

316
00:39:06,287 --> 00:39:09,597
They perch together amiably enough
above their courts,

317
00:39:09,767 --> 00:39:13,157
but when a female appears, their mood changes.

318
00:39:18,527 --> 00:39:23,078
Now each does his best
to impress her with his dancing skill.

319
00:39:28,967 --> 00:39:31,606
The strange noises are produced by the males

320
00:39:31,767 --> 00:39:37,080
snapping their wings together behind their backs
and clicking the quills of flight feathers.

321
00:39:37,247 --> 00:39:40,444
It seems as if they are flying backwards,

322
00:39:40,607 --> 00:39:45,203
because they manage to make
a mid-air turn just before they land.

323
00:39:48,167 --> 00:39:51,762
Mannequin dances vary greatly
from species to species.

324
00:39:51,927 --> 00:39:54,395
The club-winged snaps as he jumps

325
00:39:54,567 --> 00:39:59,038
and adopts a posture
that draws attention to his scarlet cap.

326
00:40:11,047 --> 00:40:15,996
Blue-crowned mannequins fly
in circles around their display perches.

327
00:40:36,527 --> 00:40:39,917
The golden-headed favours a backward shuffle.

328
00:40:46,647 --> 00:40:50,356
That movement is elaborated further
by the wire-tailed,

329
00:40:50,527 --> 00:40:55,999
who flicks the female across her chin
with long filaments projecting from his tail.

330
00:41:03,687 --> 00:41:09,284
But these long-tailed mannequins
are even more extraordinary, for both are males.

331
00:41:09,447 --> 00:41:12,245
The female has just landed on the right.

332
00:41:15,327 --> 00:41:20,720
This is a double act. The female will only
respond if two males perform together.

333
00:41:25,207 --> 00:41:28,483
But why should apparent rivals help each other?

334
00:41:28,647 --> 00:41:33,323
0ne is senior.
He is the one who owns the dancing perch.

335
00:41:33,487 --> 00:41:35,682
0nly he will mate with the female.

336
00:41:35,847 --> 00:41:39,601
The other is his apprentice
who's learning the form.

337
00:41:48,407 --> 00:41:51,399
And, indeed, this dance does take some learning.

338
00:41:52,847 --> 00:41:56,396
Young males start practising
in their second or third year.

339
00:41:56,567 --> 00:41:59,081
They get their adult plumage when they're four,

340
00:41:59,247 --> 00:42:03,206
but they still continue to dance
with younger birds as this one is doing.

341
00:42:03,367 --> 00:42:08,805
0nly when he's eight is he likely to be taken on
as an apprentice by a male who owns a court.

342
00:42:08,967 --> 00:42:11,356
If and when his senior partner dies,

343
00:42:11,527 --> 00:42:15,122
he may inherit the court
and take on an apprentice of his own.

344
00:42:15,287 --> 00:42:17,755
But even then he will only succeed in mating

345
00:42:17,927 --> 00:42:22,717
if the females are impressed
by the virtuosity of his team performance.

346
00:42:31,487 --> 00:42:37,437
This male antelope, a topi,
is also defending a court.

347
00:42:38,527 --> 00:42:42,315
It wasn't until just recently that we realised

348
00:42:42,487 --> 00:42:45,285
that any mammals displayed like this.

349
00:42:47,007 --> 00:42:51,285
And that's just what's going on
here in the plains of Kenya.

350
00:42:51,447 --> 00:42:56,043
I'm sitting on the edge
of just such a display ground.

351
00:42:57,647 --> 00:43:01,196
Immediately behind me are the two best courts.

352
00:43:01,367 --> 00:43:04,120
Each is held by a male who's trotting around,

353
00:43:04,287 --> 00:43:08,803
inspecting the half-dozen or so females,
who also have horns,

354
00:43:08,967 --> 00:43:11,356
who've come to visit him today.

355
00:43:11,527 --> 00:43:15,520
He sniffs one to discover
whether she's ready to mate.

356
00:43:18,487 --> 00:43:23,322
Within a few yards of these central courts
stands a less successful male.

357
00:43:23,487 --> 00:43:28,083
He has a court, but it's not the best,
and no females have joined him.

358
00:43:30,087 --> 00:43:32,078
The courts are so closely packed

359
00:43:32,247 --> 00:43:37,241
that rivals frequently come face to face
on the frontier between them.

360
00:43:38,447 --> 00:43:43,237
As long as they don't cross the line,
their disputes are no more than symbolic.

361
00:44:00,927 --> 00:44:05,000
As the day warms up, more and more females
thread their way through the courts

362
00:44:05,167 --> 00:44:09,763
to the central ones
held by the most successful males.

363
00:44:10,927 --> 00:44:14,044
This young calf is accompanied by its mother.

364
00:44:14,207 --> 00:44:19,201
She's ready to breed again, but not
with this male, who's a low-ranking one.

365
00:44:23,167 --> 00:44:25,283
He nonetheless tries his luck.

366
00:44:25,447 --> 00:44:28,086
In doing so, he crosses the frontier of his court

367
00:44:28,247 --> 00:44:32,798
and immediately his neighbour
gallops across to repel the invasion.

368
00:44:44,847 --> 00:44:47,077
The successful males in the centre courts

369
00:44:47,247 --> 00:44:51,320
have now acquired
almost more females than they can manage.

370
00:44:54,287 --> 00:44:58,883
There are so many
that squabbles are breaking out between them.

371
00:45:24,007 --> 00:45:28,922
The least successful bulls hold courts
around the edges of the display ground.

372
00:45:29,087 --> 00:45:32,477
It's now hot and they're very tired,
but they won't leave.

373
00:45:32,647 --> 00:45:38,643
0nly by competing do they stand a chance
of eventually graduating to a premier position.

374
00:45:40,607 --> 00:45:45,601
But these marginal courts, being close
to tall grass, are dangerous places.

375
00:45:47,047 --> 00:45:49,038
A hyena.

376
00:46:52,887 --> 00:46:55,117
Not all get away.

377
00:47:11,687 --> 00:47:16,477
For a topi, the cost of courtship
can indeed be high.

378
00:47:22,447 --> 00:47:27,441
The rewards for all these displays,
persuasions and entreaties, however,

379
00:47:27,607 --> 00:47:29,996
can certainly be great.

380
00:47:31,007 --> 00:47:36,035
Yet even coupling may not be
the ultimate achievement it might seem to be.

381
00:47:36,207 --> 00:47:38,721
An animal may have to do even more than this

382
00:47:38,887 --> 00:47:42,960
if it's to ensure that its genes
will pass on to the next generation

383
00:47:43,127 --> 00:47:45,960
and so transcend its mortality.

384
00:47:46,127 --> 00:47:48,721
That will be the final trial.

385
00:47:48,771 --> 00:47:53,321
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