1
00:00:02,066 --> 00:00:05,266
♪♪

2
00:00:05,266 --> 00:00:08,033
ATTENBOROUGH: I've recorded
many songs of the natural world

3
00:00:08,033 --> 00:00:09,566
over the years.

4
00:00:09,566 --> 00:00:12,066
Just listen to this.

5
00:00:12,066 --> 00:00:15,033
And I've learned that there is,
perhaps surprisingly,

6
00:00:15,033 --> 00:00:17,366
no scientific definition
of song.

7
00:00:17,366 --> 00:00:19,300
[ Bird singing ]

8
00:00:19,300 --> 00:00:22,333
And there are some songs
that it's impossible for me

9
00:00:22,333 --> 00:00:24,266
to imagine life without.

10
00:00:24,266 --> 00:00:28,466
But this avian choir
does not sing for us.

11
00:00:28,466 --> 00:00:32,433
What we hear is not
what the bird hears.

12
00:00:32,433 --> 00:00:35,566
Birds live on
a different timescale,

13
00:00:35,566 --> 00:00:38,766
and they can hear details
in their song

14
00:00:38,766 --> 00:00:41,966
that are impossible
for us to hear.

15
00:00:41,966 --> 00:00:45,100
It was the ability
to take recorded sound

16
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and then turn it
into a visual picture

17
00:00:47,833 --> 00:00:50,533
that enabled us
to analyze that sound

18
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and reveal its full complexity.

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DALZIELL:
It's extremely exciting.

20
00:00:54,833 --> 00:00:57,200
And it really forces us
to reconsider

21
00:00:57,200 --> 00:00:59,466
what we think of as song.

22
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KREBS: Our understanding of song
is continually developing.

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ATTENBOROUGH: How exciting it is
to think of the discoveries

24
00:01:06,466 --> 00:01:08,066
that are about to be made.

25
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[ Bird singing ]

26
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♪♪

27
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[ Birds singing ]

28
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[ Singing continues ]

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ATTENBOROUGH: On a clear
spring morning like this,

30
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the dawn chorus is at its peak.

31
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[ Singing continues ]

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There are surely few more
enchanting natural soundscapes

33
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than this.

34
00:02:25,633 --> 00:02:27,600
[ Singing continues ]

35
00:02:27,600 --> 00:02:32,333
But this avian choir
does not sing for us.

36
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[ Singing continues ]

37
00:02:36,666 --> 00:02:39,633
These are songs of seduction...

38
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and weapons of war.

39
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Males are defending territories
and attracting mates.

40
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[ Birds singing ]

41
00:02:50,300 --> 00:02:52,566
Singing is dangerous.

42
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[ Singing continues ]

43
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It reveals the bird's location
to predators.

44
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But it also offers
a huge reward --

45
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the chance to attract a female

46
00:03:04,033 --> 00:03:07,500
and pass on genes
to the next generation.

47
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That, Charles Darwin said,
is why song evolved.

48
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[ Singing continues ]

49
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It was an example of what
he called sexual selection.

50
00:03:16,866 --> 00:03:20,033
[ Singing continues ]

51
00:03:20,033 --> 00:03:22,833
But today, new discoveries
are transforming

52
00:03:22,833 --> 00:03:27,200
those long-held ideas.

53
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For this program, I have chosen
some of my favorite recordings

54
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from the natural world

55
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that have revolutionized
our understanding of song.

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♪♪

57
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There are seven recordings of it

58
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that have particular
interest for me.

59
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Some are lovely,
some are surprising,

60
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and one almost broke my heart.

61
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But all of them
broke new ground.

62
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[ Birds singing ]

63
00:03:57,500 --> 00:04:02,733
I've recorded many sounds of the
natural world over the years,

64
00:04:02,733 --> 00:04:05,733
and I've learnt that there is,
perhaps surprisingly,

65
00:04:05,733 --> 00:04:08,066
no scientific
definition of song.

66
00:04:08,066 --> 00:04:10,800
♪♪

67
00:04:10,800 --> 00:04:13,866
We tend to use the word
to describe sounds that seem,

68
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to our ears, beautiful.

69
00:04:16,133 --> 00:04:21,000
[ Birds singing ]

70
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It is, in truth,
a somewhat whimsical label.

71
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But it has been attached to some
of nature's greatest marvels.

72
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Just listen to this.

73
00:04:31,833 --> 00:04:34,866
[ Whales singing ]

74
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♪♪

75
00:04:38,666 --> 00:04:41,166
[ Singing continues ]

76
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♪♪

77
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Each of my seven chosen songs

78
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was recorded in my lifetime.

79
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[ Bird singing ]

80
00:04:54,800 --> 00:04:57,900
The oldest was made
when I was 5,

81
00:04:57,900 --> 00:05:00,766
the most recent,
just a few years ago.

82
00:05:00,766 --> 00:05:04,366
[ Birds singing ]

83
00:05:04,366 --> 00:05:08,733
None is closer to my heart
than the first one,

84
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which I made back in 1960.

85
00:05:11,800 --> 00:05:13,700
[ Laughs ]

86
00:05:13,700 --> 00:05:18,633
[ Indris singing ]

87
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♪♪

88
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Recording audio in the field
in remote parts of the world

89
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was almost unheard of.

90
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There was certainly no money
in the BBC budget

91
00:05:34,866 --> 00:05:37,400
for a sound recordist.

92
00:05:37,400 --> 00:05:40,866
But I did manage to get hold
of a very rare thing indeed,

93
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a battery-driven portable
tape recorder,

94
00:05:44,200 --> 00:05:46,500
so that
I could record sounds myself.

95
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♪♪

96
00:05:49,133 --> 00:05:51,166
It was a cumbersome
piece of kit,

97
00:05:51,166 --> 00:05:53,266
but cutting-edge at the time,

98
00:05:53,266 --> 00:05:56,333
and I was determined to use it
to record a singer

99
00:05:56,333 --> 00:06:00,033
that no one
had ever recorded before --

100
00:06:00,033 --> 00:06:03,400
Madagascar's largest lemur,
the indri.

101
00:06:03,400 --> 00:06:06,100
[ Birds chirping ]

102
00:06:06,100 --> 00:06:08,933
[ Indris singing ]

103
00:06:08,933 --> 00:06:11,366
This noise was no bird call.

104
00:06:11,366 --> 00:06:13,733
I had never heard
anything like it before.

105
00:06:13,733 --> 00:06:16,133
It must be the voice
of the indris.

106
00:06:16,133 --> 00:06:20,766
[ Singing continues ]

107
00:06:20,766 --> 00:06:22,400
Using my new equipment,

108
00:06:22,400 --> 00:06:26,366
I made the first-ever audio
recording of the indri.

109
00:06:26,366 --> 00:06:29,066
[ Singing continues ]

110
00:06:32,833 --> 00:06:37,866
But could we also capture them
on camera, as well?

111
00:06:37,866 --> 00:06:40,833
The song was so loud
that it seemed impossible

112
00:06:40,833 --> 00:06:44,400
that the animals could be more
than 20 or 30 yards away.

113
00:06:44,400 --> 00:06:46,066
But where were they?

114
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[ Singing continues ]

115
00:06:48,466 --> 00:06:50,033
Until now,

116
00:06:50,033 --> 00:06:53,200
no one had even managed
to photograph a living one.

117
00:06:53,200 --> 00:06:55,300
let alone film it.

118
00:06:55,300 --> 00:06:58,100
Infuriatingly,
the bush was so thick

119
00:06:58,100 --> 00:07:00,266
that I could see no sign
of them whatever.

120
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[ Singing continues ]

121
00:07:03,266 --> 00:07:06,866
So, the question was,
how could we get close enough

122
00:07:06,866 --> 00:07:10,933
to get a clear view of them
without frightening them?

123
00:07:10,933 --> 00:07:14,266
Well, I thought, "What about
doing it the other way around

124
00:07:14,266 --> 00:07:16,300
and trying to persuade them

125
00:07:16,300 --> 00:07:21,000
to get closer to us
by playing their calls?"

126
00:07:21,000 --> 00:07:25,666
[ Birds chirping ]

127
00:07:25,666 --> 00:07:29,400
[ Indris singing ]

128
00:07:29,400 --> 00:07:32,366
And they did exactly
what I hoped they would do.

129
00:07:32,366 --> 00:07:35,500
[ Indris singing ]

130
00:07:41,966 --> 00:07:45,000
They called in return,
came down close to us,

131
00:07:45,000 --> 00:07:47,433
stared at us, still calling.

132
00:07:47,433 --> 00:07:49,933
[ Singing continues ]

133
00:07:53,466 --> 00:07:56,100
I was thrilled.

134
00:07:56,100 --> 00:07:59,966
We had recorded their song 
and 

135
00:07:56,100 --> 00:07:59,966
filmed them singing.

136
00:07:59,966 --> 00:08:02,766
[ Singing continues ]

137
00:08:02,766 --> 00:08:06,100
But why had this trick worked?

138
00:08:06,100 --> 00:08:11,033
[ Singing continues ]

139
00:08:11,033 --> 00:08:13,866
Well, because they thought
that the song I was playing

140
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meant a competitor was close by.

141
00:08:17,166 --> 00:08:19,433
And their response was to sing.

142
00:08:19,433 --> 00:08:22,233
[ Indris singing ]

143
00:08:22,233 --> 00:08:25,800
And this suggested one thing --

144
00:08:25,800 --> 00:08:29,933
there are such things
as battle songs...

145
00:08:29,933 --> 00:08:33,000
[ Singing continues ]

146
00:08:33,000 --> 00:08:37,066
...songs that say, "Get out,
this is my territory."

147
00:08:37,066 --> 00:08:40,400
[ Singing continues ]

148
00:08:40,400 --> 00:08:43,966
♪♪

149
00:08:43,966 --> 00:08:46,033
It seemed to be a clear example

150
00:08:46,033 --> 00:08:51,200
of Darwin's theory
of sexual selection --

151
00:08:51,200 --> 00:08:56,033
a male singing to defend
his breeding patch.

152
00:08:56,033 --> 00:09:00,466
But this was still
just guesswork.

153
00:09:00,466 --> 00:09:04,800
We suspected that songs
could be weapons of war.

154
00:09:04,800 --> 00:09:07,866
But it was the next recording
that proved it.

155
00:09:07,866 --> 00:09:11,933
♪♪

156
00:09:11,933 --> 00:09:15,433
[ Great tit singing ]

157
00:09:19,800 --> 00:09:21,833
[ Great tit singing ]

158
00:09:21,833 --> 00:09:25,633
This is the song
of a male great tit,

159
00:09:25,633 --> 00:09:27,933
a call, a very simple song.

160
00:09:27,933 --> 00:09:30,566
[ Singing continues ]

161
00:09:30,566 --> 00:09:32,700
It was recorded by a scientist

162
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who's been a pioneer
in understanding animal song --

163
00:09:37,800 --> 00:09:41,000
Professor John Krebs.

164
00:09:41,000 --> 00:09:43,500
He was the one who proved
for the first time

165
00:09:43,500 --> 00:09:47,633
exactly why my playback trick
in Madagascar had worked.

166
00:09:47,633 --> 00:09:50,433
♪♪

167
00:09:50,433 --> 00:09:54,966
[ Birds chirping ]

168
00:09:54,966 --> 00:09:57,900
Spring 1975.

169
00:09:57,900 --> 00:10:00,100
[ Chirping continues ]

170
00:10:00,100 --> 00:10:02,366
Back then,
John was a young lecturer

171
00:10:02,366 --> 00:10:04,200
at the University of Oxford,

172
00:10:04,200 --> 00:10:06,266
researching the birds
in woodland

173
00:10:06,266 --> 00:10:09,666
just outside the city.

174
00:10:09,666 --> 00:10:11,700
First he plotted the territories

175
00:10:11,700 --> 00:10:15,366
of all the pairs
of great tits.

176
00:10:15,366 --> 00:10:19,066
Next, he recorded
the songs of the males.

177
00:10:19,066 --> 00:10:21,800
[ Great tit singing ]

178
00:10:25,866 --> 00:10:28,566
Female great tits do not sing.

179
00:10:30,900 --> 00:10:33,400
KREBS: Then, on a particular
morning in February,

180
00:10:33,400 --> 00:10:37,900
I came out with mist nets
to catch the birds,

181
00:10:37,900 --> 00:10:41,900
and I caught all the pairs
of birds that were in the wood.

182
00:10:41,900 --> 00:10:45,833
ATTENBOROUGH:
Now there were no great tits,

183
00:10:45,833 --> 00:10:49,266
just empty great tit
territories.

184
00:10:49,266 --> 00:10:53,666
In some, John replaced the
great tits with loud speakers

185
00:10:53,666 --> 00:10:55,800
that played the sounds
of the birds

186
00:10:55,800 --> 00:10:58,500
that he'd temporarily removed.

187
00:10:58,500 --> 00:11:01,300
[ Great tit singing ]

188
00:11:01,300 --> 00:11:03,533
If the song
was a "keep out" signal,

189
00:11:03,533 --> 00:11:06,866
then new great tits
would avoid these patches.

190
00:11:06,866 --> 00:11:10,833
[ Singing continues ]

191
00:11:10,833 --> 00:11:13,633
Other territories
were left silent.

192
00:11:13,633 --> 00:11:18,266
No speakers,
no great tit song.

193
00:11:18,266 --> 00:11:20,166
New great tits should realize

194
00:11:20,166 --> 00:11:22,633
these spaces were empty
and available

195
00:11:22,633 --> 00:11:24,566
and settle there quickly.

196
00:11:24,566 --> 00:11:27,033
[ Great tit singing ]

197
00:11:27,033 --> 00:11:30,833
But how would John know that
it was due to a great tit song

198
00:11:30,833 --> 00:11:34,933
that newcomers
had been deterred?

199
00:11:34,933 --> 00:11:39,233
Perhaps any sound would
have had the same effect.

200
00:11:39,233 --> 00:11:41,666
So in some territories he played

201
00:11:41,666 --> 00:11:44,333
a recording of a tin whistle.

202
00:11:44,333 --> 00:11:47,400
[ Tin whistle playing ]

203
00:11:47,400 --> 00:11:49,033
He could have chosen anything,

204
00:11:49,033 --> 00:11:52,466
as long as it sounded nothing
like a great tit.

205
00:11:52,466 --> 00:11:54,633
KREBS: And then I watched
to see what happened.

206
00:11:54,633 --> 00:11:56,866
And new birds came into the wood

207
00:11:56,866 --> 00:11:58,933
because this is
a prime breeding area,

208
00:11:58,933 --> 00:12:00,966
so birds love
to come here to breed.

209
00:12:00,966 --> 00:12:04,633
♪♪

210
00:12:04,633 --> 00:12:07,066
ATTENBOROUGH: John discovered
that the first territories

211
00:12:07,066 --> 00:12:10,300
that were taken
were the silent territories

212
00:12:10,300 --> 00:12:14,066
and the ones
with the tin whistle.

213
00:12:14,066 --> 00:12:16,800
Crucially, the territories
in which the great tit song

214
00:12:16,800 --> 00:12:21,233
was played remained empty
of new great tits.

215
00:12:21,233 --> 00:12:24,600
KREBS: By looking at the detail
of that pattern of settling,

216
00:12:24,600 --> 00:12:27,666
I was able to show,
experimentally,

217
00:12:27,666 --> 00:12:31,000
that song
isan effective
"keep out" signal.

218
00:12:31,000 --> 00:12:35,666
[ Great tit singing ]

219
00:12:35,666 --> 00:12:39,366
ATTENBOROUGH: Professor Krebs'
predictions were exactly right.

220
00:12:39,366 --> 00:12:43,733
The song was a "keep out" signal
to other great tits.

221
00:12:43,733 --> 00:12:47,400
[ Great tit singing ]

222
00:12:47,400 --> 00:12:50,600
For the very first time,
there was scientific evidence

223
00:12:50,600 --> 00:12:55,866
that song was being used
to intimidate rivals,

224
00:12:55,866 --> 00:12:58,066
just as I had seen
with the indris

225
00:12:58,066 --> 00:13:02,300
in Madagascar in the '60s.

226
00:13:02,300 --> 00:13:05,933
How astonishing that
it was only in 1975

227
00:13:05,933 --> 00:13:09,966
that this was proved
for the first time.

228
00:13:09,966 --> 00:13:13,666
The song of the great tit
had made history.

229
00:13:13,666 --> 00:13:16,433
♪♪

230
00:13:16,433 --> 00:13:18,766
[ Great tit singing ]

231
00:13:18,766 --> 00:13:23,400
[ Birds singing ]

232
00:13:23,400 --> 00:13:25,633
Open a window in spring,

233
00:13:25,633 --> 00:13:28,133
and these are the singers
that serenade us...

234
00:13:28,133 --> 00:13:30,700
[ Singing continues ]

235
00:13:30,700 --> 00:13:34,333
...songbirds.

236
00:13:34,333 --> 00:13:37,900
They make up about half
of the 10,000 species of birds

237
00:13:37,900 --> 00:13:41,133
in the world.

238
00:13:41,133 --> 00:13:44,666
Five of my seven songs
are sung by them.

239
00:13:44,666 --> 00:13:47,700
[ Singing continues ]

240
00:13:47,700 --> 00:13:50,300
Birds have the most advanced
vocal organs

241
00:13:50,300 --> 00:13:54,200
in the entire natural world.

242
00:13:54,200 --> 00:13:58,200
We have our voice box
at the top of our windpipe.

243
00:13:58,200 --> 00:14:01,633
But their equivalent
is at the base of theirs.

244
00:14:01,633 --> 00:14:04,600
It's an organ called a syrinx.

245
00:14:04,600 --> 00:14:08,033
They're the only creatures
on Earth to have one of these.

246
00:14:08,033 --> 00:14:13,300
And the syrinx of the songbird
is the most complex of them all.

247
00:14:13,300 --> 00:14:17,200
As breath passes through it,
muscles contract and vibrate,

248
00:14:17,200 --> 00:14:19,800
creating
the sounds we call song.

249
00:14:19,800 --> 00:14:21,566
It can produce different notes

250
00:14:21,566 --> 00:14:24,066
from the left and the right
sides simultaneously.

251
00:14:24,066 --> 00:14:26,233
[ Bird singing ]

252
00:14:26,233 --> 00:14:28,533
It's like having two voice boxes

253
00:14:28,533 --> 00:14:30,566
that can operate
at the same time.

254
00:14:30,566 --> 00:14:32,566
[ Birds singing ]

255
00:14:32,566 --> 00:14:34,366
So this is how songbirds

256
00:14:34,366 --> 00:14:39,166
can perform such unparalleled
feats of vocal gymnastics.

257
00:14:39,166 --> 00:14:43,300
But working out why they do,
is far more complex.

258
00:14:43,300 --> 00:14:45,500
[ Singing continues ]

259
00:14:48,933 --> 00:14:54,566
Each note lasts just a tiny
moment and then disappears.

260
00:14:54,566 --> 00:14:58,066
[ Singing continues ]

261
00:14:58,066 --> 00:15:02,766
That presents anyone who wants
to study it with a problem.

262
00:15:02,766 --> 00:15:04,866
[ Birds singing ]

263
00:15:04,866 --> 00:15:07,966
But there are two relatively
recent inventions

264
00:15:07,966 --> 00:15:12,533
that have helped us
to capture songs.

265
00:15:12,533 --> 00:15:15,166
It was with a gun mic
like this --

266
00:15:15,166 --> 00:15:17,300
inside its windshield --

267
00:15:17,300 --> 00:15:21,200
that John Krebs
caught the fleeting sound

268
00:15:21,200 --> 00:15:23,633
of the great tit.

269
00:15:23,633 --> 00:15:27,600
But it was the ability to take
that recorded sound

270
00:15:27,600 --> 00:15:30,933
and then turn it into
a visual picture

271
00:15:30,933 --> 00:15:33,900
that enabled us
to analyze that sound

272
00:15:33,900 --> 00:15:38,033
and reveal its full complexity.

273
00:15:38,033 --> 00:15:39,366
[ Great tit singing ]

274
00:15:39,366 --> 00:15:42,900
This is an animation of the male
great tit's song,

275
00:15:42,900 --> 00:15:47,000
generated by a machine
called a spectrograph.

276
00:15:47,000 --> 00:15:48,200
[ Great tit singing ]

277
00:15:48,200 --> 00:15:50,166
It changes the song
into an image

278
00:15:50,166 --> 00:15:53,200
that's possible to read.

279
00:15:53,200 --> 00:15:56,266
Slowed down, we can see
that the great tit's song

280
00:15:56,266 --> 00:15:57,533
is relatively simple.

281
00:15:57,533 --> 00:15:59,133
[ Great tit singing ]

282
00:15:59,133 --> 00:16:01,100
It's composed of two notes,

283
00:16:01,100 --> 00:16:05,300
one high and one low, repeated.

284
00:16:05,300 --> 00:16:07,100
[ Great tit singing ]

285
00:16:07,100 --> 00:16:08,866
What we hear is very similar

286
00:16:08,866 --> 00:16:12,466
to what we can see
on the spectrograph.

287
00:16:12,466 --> 00:16:15,333
But compare that to the song
of the male wren.

288
00:16:15,333 --> 00:16:19,566
[ Wren singing ]

289
00:16:19,566 --> 00:16:24,166
What we hear is not
what the bird hears.

290
00:16:24,166 --> 00:16:28,066
Birds live on a different
timescale,

291
00:16:28,066 --> 00:16:31,333
at a different pace from us.

292
00:16:31,333 --> 00:16:35,500
And they can hear details
in their song

293
00:16:35,500 --> 00:16:40,966
that are impossible
for us to hear.

294
00:16:40,966 --> 00:16:43,166
It's only when we use
a spectrogram

295
00:16:43,166 --> 00:16:45,100
that these details are revealed.

296
00:16:47,700 --> 00:16:48,733
A trill...

297
00:16:48,733 --> 00:16:50,000
[ Trill plays ]

298
00:16:50,000 --> 00:16:51,200
...a connecting note...

299
00:16:51,200 --> 00:16:52,566
[ Note plays ]

300
00:16:52,566 --> 00:16:53,533
...another trill...

301
00:16:53,533 --> 00:16:54,900
[ Trill plays ]

302
00:16:54,900 --> 00:16:57,600
...and then a rapid burst
of trills at the end.

303
00:16:57,600 --> 00:16:59,166
[ Trills playing ]

304
00:16:59,166 --> 00:17:02,966
Now we can see that there are,
perhaps, a hundred notes or more

305
00:17:02,966 --> 00:17:06,133
in a song that may last
only a few seconds.

306
00:17:06,133 --> 00:17:09,233
[ Wren singing ]

307
00:17:09,233 --> 00:17:11,666
[ Bird singing ]

308
00:17:15,566 --> 00:17:17,833
[ Singing continues ]

309
00:17:22,133 --> 00:17:25,600
What the spectrograms show
are these songs

310
00:17:25,600 --> 00:17:29,066
are far more complicated
and complex

311
00:17:29,066 --> 00:17:32,200
than we could possibly
have imagined.

312
00:17:32,200 --> 00:17:35,366
But why complicate things so?

313
00:17:35,366 --> 00:17:38,666
The calls of the indri
and the great tit

314
00:17:38,666 --> 00:17:41,566
work perfectly well.

315
00:17:41,566 --> 00:17:44,600
The answer, of course, is sex.

316
00:17:44,600 --> 00:17:46,633
♪♪

317
00:17:46,633 --> 00:17:49,866
[ Birds singing ]

318
00:17:49,866 --> 00:17:52,700
♪♪

319
00:17:52,700 --> 00:17:55,200
That is the reason
why so many birds

320
00:17:55,200 --> 00:17:58,166
have such complex mating songs.

321
00:17:58,166 --> 00:18:02,566
[ Singing continues ]

322
00:18:02,566 --> 00:18:05,766
Females seem to prefer them.

323
00:18:05,766 --> 00:18:08,300
The more intricate and detailed
the song is,

324
00:18:08,300 --> 00:18:10,666
the better the male's chances.

325
00:18:10,666 --> 00:18:15,333
[ Singing continues ]

326
00:18:15,333 --> 00:18:18,700
And my third song
helps to explain why.

327
00:18:18,700 --> 00:18:21,500
♪♪

328
00:18:21,500 --> 00:18:27,233
[ Nightingale singing ]

329
00:18:27,233 --> 00:18:29,266
It's a recording
of a nightingale

330
00:18:29,266 --> 00:18:31,766
that is my next chosen song.

331
00:18:31,766 --> 00:18:35,200
[ Nightingale singing ]

332
00:18:35,200 --> 00:18:38,633
This is a male singing
for a mate.

333
00:18:38,633 --> 00:18:40,033
[ Singing continues ]

334
00:18:40,033 --> 00:18:41,933
Just as with the great tit,

335
00:18:41,933 --> 00:18:45,100
the females do not sing.

336
00:18:45,100 --> 00:18:48,500
But they are the ones
the males are singing for.

337
00:18:48,500 --> 00:18:52,333
So, why do they prefer
more complex songs?

338
00:18:52,333 --> 00:18:55,433
[ Nightingale singing ]

339
00:18:55,433 --> 00:18:58,533
♪♪

340
00:18:58,533 --> 00:19:02,333
It's a question that has puzzled
scientists for centuries.

341
00:19:02,333 --> 00:19:04,866
♪♪

342
00:19:04,866 --> 00:19:07,933
Charles Darwin's answer
was that the females

343
00:19:07,933 --> 00:19:10,766
have an aesthetic sense.

344
00:19:10,766 --> 00:19:13,833
After all, human beings
appreciate beauty.

345
00:19:13,833 --> 00:19:16,566
Why shouldn't other animals
do so, too?

346
00:19:16,566 --> 00:19:18,933
♪♪

347
00:19:18,933 --> 00:19:22,133
But the question Darwin
didn't answer was,

348
00:19:22,133 --> 00:19:25,100
why
should the females
have an aesthetic sense?

349
00:19:28,400 --> 00:19:30,500
Here on the streets of Berlin,

350
00:19:30,500 --> 00:19:33,266
we might just find the answer.

351
00:19:33,266 --> 00:19:35,633
[ Birds singing ]

352
00:19:35,633 --> 00:19:38,733
Spring attracts over
2,000 nightingales

353
00:19:38,733 --> 00:19:41,466
to this city each year.

354
00:19:41,466 --> 00:19:45,100
They flock to Berlin because
it's filled with green space,

355
00:19:45,100 --> 00:19:48,600
much of which
has been left untamed.

356
00:19:48,600 --> 00:19:51,500
And it's these wild places
that they love.

357
00:19:51,500 --> 00:19:55,866
[ Nightingales singing ]

358
00:19:55,866 --> 00:20:00,700
In one of its most popular
parks -- a male nightingale.

359
00:20:00,700 --> 00:20:03,733
[ Nightingale singing ]

360
00:20:03,733 --> 00:20:05,266
He, like the other males,

361
00:20:05,266 --> 00:20:07,666
arrived from Africa
a few weeks ago

362
00:20:07,666 --> 00:20:11,800
and has spent his time singing
to defend a breeding patch.

363
00:20:11,800 --> 00:20:13,800
[ Nightingale singing ]

364
00:20:13,800 --> 00:20:19,400
But tonight, when the lights go
out, he will change his tune...

365
00:20:19,400 --> 00:20:22,633
because the females
have arrived.

366
00:20:22,633 --> 00:20:26,900
[ Nightingale singing ]

367
00:20:26,900 --> 00:20:30,066
Nightingales migrate at night.

368
00:20:30,066 --> 00:20:33,333
And when the females fly in
under cover of dark,

369
00:20:33,333 --> 00:20:36,333
they are met
with songs of seduction.

370
00:20:36,333 --> 00:20:39,233
[ Nightingales singing ]

371
00:20:43,400 --> 00:20:46,733
Dr. Conny Landgraf
made our recording

372
00:20:46,733 --> 00:20:48,333
of the nightingale's song.

373
00:20:48,333 --> 00:20:50,800
[ Nightingale singing ]

374
00:20:53,866 --> 00:20:56,400
LANDGRAF:
So, right now there's one male.

375
00:20:56,400 --> 00:20:57,733
No. There is a second male

376
00:20:57,733 --> 00:21:01,433
So, it's already two males
in a vocal contest.

377
00:21:01,433 --> 00:21:03,333
[ Singing continues ]

378
00:21:03,333 --> 00:21:07,566
What the females do is that they
do not take the first male

379
00:21:07,566 --> 00:21:09,000
that comes their way,

380
00:21:09,000 --> 00:21:13,366
but they prospect and inspect
different male territories.

381
00:21:13,366 --> 00:21:15,200
And this is like a speed-dating

382
00:21:15,200 --> 00:21:18,300
that is actually going on
in the middle of the night.

383
00:21:18,300 --> 00:21:20,933
[ Singing continues ]

384
00:21:20,933 --> 00:21:23,700
ATTENBOROUGH:
Each male sings his heart out.

385
00:21:23,700 --> 00:21:26,666
And the females listen.

386
00:21:26,666 --> 00:21:28,566
[ Ding! ]
Time's up.

387
00:21:28,566 --> 00:21:31,666
What does the next
potential mate sound like?

388
00:21:31,666 --> 00:21:33,800
[ Ding! ]
Time's up again.

389
00:21:33,800 --> 00:21:35,733
Does the next one
have a better song?

390
00:21:35,733 --> 00:21:37,500
[ Nightingale singing ]

391
00:21:37,500 --> 00:21:39,533
[ Ding! ]

392
00:21:39,533 --> 00:21:42,000
[ Nightingale singing ]

393
00:21:42,000 --> 00:21:44,366
[ Ding! ]
Nightingales have extremely

394
00:21:44,366 --> 00:21:49,666
large song repertoires,
up to 250 songs.

395
00:21:49,666 --> 00:21:53,233
LANDGRAF: And also
they are able to produce

396
00:21:53,233 --> 00:21:57,200
really challenging syllables
and phrases,

397
00:21:57,200 --> 00:22:00,033
thinking of trill
or buzz elements.

398
00:22:00,033 --> 00:22:03,766
So, these are very fast,
repeated single notes.

399
00:22:03,766 --> 00:22:06,533
So, this is remarkable.

400
00:22:06,533 --> 00:22:10,033
ATTENBOROUGH:
The more complex his song,

401
00:22:10,033 --> 00:22:13,800
the more beautiful
it seems to the female.

402
00:22:13,800 --> 00:22:15,066
But why?

403
00:22:15,066 --> 00:22:17,166
Does the female have
an aesthetic sense,

404
00:22:17,166 --> 00:22:20,100
as Darwin suggested?

405
00:22:20,100 --> 00:22:24,666
Conny and her team set up
an experiment to find out.

406
00:22:24,666 --> 00:22:27,100
First, they recorded
males singing

407
00:22:27,100 --> 00:22:30,266
at the beginning of spring.

408
00:22:30,266 --> 00:22:34,033
Then they set up cameras
to record nightingale nests

409
00:22:34,033 --> 00:22:36,066
later in the season.

410
00:22:36,066 --> 00:22:38,133
♪♪

411
00:22:38,133 --> 00:22:42,900
Male nightingales play a crucial
role in feeding chicks.

412
00:22:42,900 --> 00:22:46,766
♪♪

413
00:22:46,766 --> 00:22:48,733
[ Nightingale singing ]

414
00:22:48,733 --> 00:22:50,233
LANDGRAF:
What we found in the end

415
00:22:50,233 --> 00:22:53,400
was that there was indeed
a very strong correlation

416
00:22:53,400 --> 00:22:57,300
between the song
and feeding rates at the nest.

417
00:22:57,300 --> 00:23:01,266
So, it's like a promise that
the males give to the females

418
00:23:01,266 --> 00:23:05,400
to be good fathers.

419
00:23:05,400 --> 00:23:08,433
So, for example,
a male could be saying,

420
00:23:08,433 --> 00:23:11,300
"Hey, there.
I'm a healthy, strong man.

421
00:23:11,300 --> 00:23:15,433
"I know this area and all the
best feeding places very well,

422
00:23:15,433 --> 00:23:19,666
so come settle down
and mate with me."

423
00:23:19,666 --> 00:23:22,600
[ Nightingale singing ]

424
00:23:22,600 --> 00:23:24,633
ATTENBOROUGH:
Females, Darwin said,

425
00:23:24,633 --> 00:23:28,466
chose the males
with the most beautiful songs.

426
00:23:28,466 --> 00:23:32,066
And my third recording
has demonstrated why --

427
00:23:32,066 --> 00:23:34,033
better singers
are better fathers.

428
00:23:34,033 --> 00:23:36,000
[ Nightingale singing ]

429
00:23:36,000 --> 00:23:39,966
Song can be a promise
of devoted parenthood.

430
00:23:39,966 --> 00:23:42,333
[ Nightingales singing ]

431
00:23:45,066 --> 00:23:52,800
♪♪

432
00:23:52,800 --> 00:23:54,533
There are some songs

433
00:23:54,533 --> 00:23:59,066
that it's impossible for me
to imagine life without...

434
00:23:59,066 --> 00:24:01,233
[ Bird singing ]

435
00:24:01,233 --> 00:24:05,633
...songs that accompany
our daily lives.

436
00:24:05,633 --> 00:24:08,166
It's one of the most
characteristic sounds

437
00:24:08,166 --> 00:24:10,466
and, to my ears,
one of the most delightful

438
00:24:10,466 --> 00:24:12,766
of the English winter --

439
00:24:12,766 --> 00:24:15,200
the song of the robin.

440
00:24:15,200 --> 00:24:18,700
[ Robins singing ]

441
00:24:18,700 --> 00:24:20,900
These are the songs
that Charles Darwin

442
00:24:20,900 --> 00:24:23,766
would have listened to as a boy.

443
00:24:23,766 --> 00:24:25,800
And much of our research
into song

444
00:24:25,800 --> 00:24:30,466
has centered on British species.

445
00:24:30,466 --> 00:24:32,866
Indeed, for much
of the last century,

446
00:24:32,866 --> 00:24:37,133
we thought birdsong originated
here, in northern latitudes.

447
00:24:37,133 --> 00:24:39,866
[ Birds singing ]

448
00:24:39,866 --> 00:24:41,533
But what if Darwin
had been raised

449
00:24:41,533 --> 00:24:44,500
on the other side of the world?

450
00:24:44,500 --> 00:24:48,866
Would his theories about song
have been different?

451
00:24:48,866 --> 00:24:52,300
[ Birds singing ]

452
00:24:52,300 --> 00:24:54,900
The forests of Australia.

453
00:24:54,900 --> 00:24:57,533
[ Singing continues ]

454
00:24:57,533 --> 00:25:02,233
♪♪

455
00:25:02,233 --> 00:25:04,433
Here, scientists are
in the process

456
00:25:04,433 --> 00:25:08,233
of changing many
of our old ideas about song.

457
00:25:08,233 --> 00:25:12,966
[ Singing continues ]

458
00:25:12,966 --> 00:25:17,166
They've found fossil and DNA
evidence of early songbirds

459
00:25:17,166 --> 00:25:21,366
which show that
this, 
in fact,
is where song began.

460
00:25:21,366 --> 00:25:25,766
[ Birds singing ]

461
00:25:25,766 --> 00:25:27,566
It was here in Australia

462
00:25:27,566 --> 00:25:31,933
that the ancestors
of all songbirds first evolved.

463
00:25:31,933 --> 00:25:34,700
[ Birds singing ]

464
00:25:34,700 --> 00:25:40,400
♪♪

465
00:25:40,400 --> 00:25:44,366
Song number four is from
one of the original songbird's

466
00:25:44,366 --> 00:25:48,200
most remarkable descendants.

467
00:25:48,200 --> 00:25:51,966
And it's one that amazes me
every time I hear it.

468
00:25:51,966 --> 00:25:56,733
[ Superb lyrebird singing ]

469
00:25:58,400 --> 00:26:02,866
It was recorded in the forests
just outside Melbourne.

470
00:26:02,866 --> 00:26:05,433
And was the first time
that wild birdsong

471
00:26:05,433 --> 00:26:08,266
had ever been broadcast
in Australia.

472
00:26:08,266 --> 00:26:10,633
[ Superb lyrebirds singing ]

473
00:26:14,500 --> 00:26:16,900
The song of the lyrebird,
in my view,

474
00:26:16,900 --> 00:26:20,466
is one of the most complex
and beautiful

475
00:26:20,466 --> 00:26:23,500
in the whole
of the natural world.

476
00:26:23,500 --> 00:26:26,600
And what gives it
its complexity,

477
00:26:26,600 --> 00:26:30,466
is the talent that the lyrebird
has for mimicry.

478
00:26:32,200 --> 00:26:34,566
Crimson parrot.

479
00:26:34,566 --> 00:26:38,100
[ Superb lyrebird singing ]

480
00:26:38,100 --> 00:26:40,000
The kookaburra.

481
00:26:40,000 --> 00:26:44,033
[ Superb lyrebird singing ]

482
00:26:44,033 --> 00:26:47,300
The descendants of that
lyrebird, I'm happy to say,

483
00:26:47,300 --> 00:26:50,533
are still singing
in those forests.

484
00:26:50,533 --> 00:26:55,833
And I have been lucky enough
to listen to one of them myself.

485
00:26:55,833 --> 00:27:00,433
It was the 1990s when
the BBC series "Life of Birds"

486
00:27:00,433 --> 00:27:02,633
took me to Australia.

487
00:27:02,633 --> 00:27:05,066
♪♪

488
00:27:05,066 --> 00:27:07,300
I wanted to film a lyrebird

489
00:27:07,300 --> 00:27:09,966
who was
the most astounding mimic.

490
00:27:09,966 --> 00:27:13,366
[ Superb lyrebird singing ]

491
00:27:13,366 --> 00:27:16,466
To persuade females to come
close and admire his plumes,

492
00:27:16,466 --> 00:27:19,333
he sings the most complex song
he can manage,

493
00:27:19,333 --> 00:27:22,966
and he does that by copying
the songs of all the other birds

494
00:27:22,966 --> 00:27:26,700
he hears around him,
such as the kookaburra.

495
00:27:26,700 --> 00:27:30,766
[ Superb lyrebird singing ]

496
00:27:30,766 --> 00:27:34,466
He can imitate the calls of
at least 20 different species.

497
00:27:34,466 --> 00:27:38,500
[ Singing continues ]

498
00:27:38,500 --> 00:27:41,533
He also, in his attempt
to out-sing his rivals,

499
00:27:41,533 --> 00:27:45,400
incorporates other sounds
that he hears in the forest.

500
00:27:45,400 --> 00:27:46,633
[ Superb lyrebird
mimicking clicking ]

501
00:27:46,633 --> 00:27:48,933
That was a camera shutter.

502
00:27:48,933 --> 00:27:53,400
[ Superb lyrebird singing ]

503
00:27:53,400 --> 00:27:54,933
[ Superb lyrebird
mimicking clicking ]

504
00:27:54,933 --> 00:27:56,033
And again.

505
00:27:56,033 --> 00:27:58,666
[ Superb lyrebird singing ]

506
00:27:58,666 --> 00:28:00,000
[ Superb lyrebird
mimicking clicking ]

507
00:28:00,000 --> 00:28:03,466
And now a camera
with a motor drive.

508
00:28:03,466 --> 00:28:05,466
[ Superb lyrebird
mimicking clicking, whirring ]

509
00:28:05,466 --> 00:28:09,333
[ Superb lyrebird singing
rhythmically ]

510
00:28:09,333 --> 00:28:11,366
And that's a car alarm.

511
00:28:11,366 --> 00:28:14,433
[ Singing continues ]

512
00:28:19,966 --> 00:28:22,166
And now the sounds of foresters

513
00:28:22,166 --> 00:28:24,766
and their chainsaws
working nearby.

514
00:28:24,766 --> 00:28:28,933
[ Superb lyrebird
mimicking buzzing, clacking ]

515
00:28:33,033 --> 00:28:35,733
Since this remarkable clip
was broadcast,

516
00:28:35,733 --> 00:28:38,300
millions of people
have watched it online.

517
00:28:40,433 --> 00:28:44,466
But scientists have discovered
a lot more about lyrebird song

518
00:28:44,466 --> 00:28:46,633
since that recording was made.

519
00:28:46,633 --> 00:28:49,200
That particular bird
was accustomed

520
00:28:49,200 --> 00:28:52,633
to the presence
of human beings nearby.

521
00:28:52,633 --> 00:28:57,733
But much wilder birds produce
something even more fascinating.

522
00:28:57,733 --> 00:28:59,500
♪♪

523
00:28:59,500 --> 00:29:03,000
Sunrise,
Sherbrooke Forest today.

524
00:29:03,000 --> 00:29:05,333
[ Birds singing ]

525
00:29:05,333 --> 00:29:10,166
One voice in the dawn chorus
is louder than any other --

526
00:29:10,166 --> 00:29:12,266
the male lyrebird.

527
00:29:12,266 --> 00:29:14,866
[ Superb lyrebird singing ]

528
00:29:14,866 --> 00:29:19,500
♪♪

529
00:29:19,500 --> 00:29:21,166
It's the breeding season,

530
00:29:21,166 --> 00:29:24,166
and they're busy
trying to attract mates.

531
00:29:24,166 --> 00:29:27,866
♪♪

532
00:29:27,866 --> 00:29:30,833
[ Superb lyrebird singing ]

533
00:29:30,833 --> 00:29:33,266
Clearing undergrowth
from the forest floor

534
00:29:33,266 --> 00:29:37,200
creates an arena
for his mating display.

535
00:29:37,200 --> 00:29:40,333
[ Singing continues ]

536
00:29:44,066 --> 00:29:47,833
Once the stage is set,
the show can begin.

537
00:29:47,833 --> 00:29:52,166
[ Singing continues ]

538
00:29:52,166 --> 00:29:55,233
It's unlike any other
in the natural world.

539
00:29:55,233 --> 00:29:58,633
[ Singing continues ]

540
00:29:58,633 --> 00:30:02,033
Since I heard this song,
scientists have analyzed it

541
00:30:02,033 --> 00:30:04,566
and broken it down into parts.

542
00:30:04,566 --> 00:30:08,400
[ Superb lyrebird singing ]

543
00:30:08,400 --> 00:30:11,033
Song A comes first.

544
00:30:11,033 --> 00:30:13,366
[ Singing continues ]

545
00:30:16,633 --> 00:30:20,300
Now, Song B,
a loud, low shriek

546
00:30:20,300 --> 00:30:22,466
which alternates with Song C,

547
00:30:22,466 --> 00:30:25,233
a quiet, very soft
clicking sound.

548
00:30:25,233 --> 00:30:28,033
[ Singing continues ]

549
00:30:32,866 --> 00:30:34,833
A female arrives.

550
00:30:34,833 --> 00:30:36,866
♪♪

551
00:30:36,866 --> 00:30:39,233
But, no, she loses interest.

552
00:30:39,233 --> 00:30:42,200
♪♪

553
00:30:42,200 --> 00:30:46,766
What he does next will need
to be even more impressive.

554
00:30:46,766 --> 00:30:50,033
[ Birds singing ]

555
00:30:50,033 --> 00:30:56,700
♪♪

556
00:30:56,700 --> 00:31:00,600
Few have analyzed the grand
finale of the male lyrebird song

557
00:31:00,600 --> 00:31:05,633
more intensively
than Dr. Anastasia Dalziell.

558
00:31:05,633 --> 00:31:10,466
She and her team were the
first ones to film it properly.

559
00:31:10,466 --> 00:31:12,933
DALZIELL: We thought,
"No one's gonna believe us

560
00:31:12,933 --> 00:31:14,366
until we've actually filmed it."

561
00:31:14,366 --> 00:31:17,900
It's really not like anything
else that has been described

562
00:31:17,900 --> 00:31:20,966
previously in birds
or any other animals.

563
00:31:20,966 --> 00:31:24,933
♪♪

564
00:31:24,933 --> 00:31:26,600
ATTENBOROUGH: It was
by studying the recordings

565
00:31:26,600 --> 00:31:28,200
from their remote camera

566
00:31:28,200 --> 00:31:29,966
that the team
were able to understand

567
00:31:29,966 --> 00:31:34,700
the real secret
of the male lyrebird song.

568
00:31:34,700 --> 00:31:37,500
And it is this footage,
together with our own,

569
00:31:37,500 --> 00:31:40,166
that enables us to show
this remarkable behavior

570
00:31:40,166 --> 00:31:44,800
on television
for the first time.

571
00:31:44,800 --> 00:31:48,400
Having sung Song A, B and C --
and been rejected --

572
00:31:48,400 --> 00:31:51,133
the male now begins Song D.

573
00:31:51,133 --> 00:31:53,366
DALZIELL:
So, this final song --

574
00:31:53,366 --> 00:31:56,300
it's a sound of a flock
of small birds...

575
00:31:56,300 --> 00:31:57,900
[ Superb lyrebird singing ]

576
00:31:57,900 --> 00:32:01,000
...mobbing reacting to a
stationary or a hidden predator

577
00:32:01,000 --> 00:32:02,633
like a snake.

578
00:32:02,633 --> 00:32:05,233
And this was totally bizarre.

579
00:32:05,233 --> 00:32:08,900
ATTENBOROUGH: So, why is he
imitating a flock of birds?

580
00:32:08,900 --> 00:32:10,300
[ Singing continues ]

581
00:32:10,300 --> 00:32:12,566
Well, a predator means danger,

582
00:32:12,566 --> 00:32:16,600
so at the sound of an
alarm call, the female freezes.

583
00:32:16,600 --> 00:32:20,900
[ Singing continues ]

584
00:32:20,900 --> 00:32:23,566
The forest is no longer
a safe place.

585
00:32:23,566 --> 00:32:27,366
[ Singing continues ]

586
00:32:27,366 --> 00:32:31,100
Now the male takes advantage
of her panic.

587
00:32:31,100 --> 00:32:33,833
He jumps on top of her to mate.

588
00:32:33,833 --> 00:32:36,000
♪♪

589
00:32:36,000 --> 00:32:38,800
It's hard for us to see her
under his feathers.

590
00:32:38,800 --> 00:32:43,400
And it's hard for her to see out
from under them.

591
00:32:43,400 --> 00:32:47,666
He is doing everything he can
to disorientate and confuse her.

592
00:32:47,666 --> 00:32:52,333
♪♪

593
00:32:52,333 --> 00:32:55,400
DALZIELL: The male is actually
telling her a big fib --

594
00:32:55,400 --> 00:32:58,300
"Don't leave me because out
there there's a hidden predator

595
00:32:58,300 --> 00:32:59,800
that you haven't seen."

596
00:32:59,800 --> 00:33:02,566
To put it another way,
it's like saying,

597
00:33:02,566 --> 00:33:04,266
"Baby, it's dangerous outside.

598
00:33:04,266 --> 00:33:07,833
Come back here with me,
where it's nice and safe."

599
00:33:07,833 --> 00:33:11,533
♪♪

600
00:33:11,533 --> 00:33:17,466
ATTENBOROUGH: The lyrebird is,
in fact, a bird that tells lies.

601
00:33:17,466 --> 00:33:21,966
His song is
an acoustic illusion.

602
00:33:21,966 --> 00:33:24,500
Up to now,
scientists had thought that song

603
00:33:24,500 --> 00:33:27,833
was an honest signal
from the male.

604
00:33:27,833 --> 00:33:33,733
But it seems song can also be
manipulative and false.

605
00:33:33,733 --> 00:33:40,633
♪♪

606
00:33:40,633 --> 00:33:43,400
[ Birds singing ]

607
00:33:43,400 --> 00:33:47,333
Not far away, in the
Blue Mountains near Sydney,

608
00:33:47,333 --> 00:33:52,333
scientist Victoria Austin
is studying the female lyrebird.

609
00:33:52,333 --> 00:33:55,133
♪♪

610
00:33:55,133 --> 00:33:56,566
What she's listening for

611
00:33:56,566 --> 00:34:00,400
is something very few
people have heard.

612
00:34:00,400 --> 00:34:04,000
AUSTIN: So, what I'm doing now
is just preparing my recorder

613
00:34:04,000 --> 00:34:06,966
because we're about
to head to a nest

614
00:34:06,966 --> 00:34:09,566
and we're hoping to be able
to record the female lyrebird

615
00:34:09,566 --> 00:34:13,166
that resides in that area.

616
00:34:13,166 --> 00:34:14,866
ATTENBOROUGH:
The female lyrebird

617
00:34:14,866 --> 00:34:17,533
is the opposite
of her flashy mate.

618
00:34:17,533 --> 00:34:19,566
She's secretive.

619
00:34:21,700 --> 00:34:25,466
When she
isseen, she's often
mistaken for a juvenile male.

620
00:34:27,600 --> 00:34:31,133
To most people, she's invisible.

621
00:34:31,133 --> 00:34:36,100
But Victoria knows
how to find her.

622
00:34:36,100 --> 00:34:41,333
This old nest suggests
that she may be nearby.

623
00:34:41,333 --> 00:34:42,533
And there she is.

624
00:34:42,533 --> 00:34:44,333
[ Superb lyrebird singing ]

625
00:34:44,333 --> 00:34:48,433
This rarely heard sound
is her whistle song.

626
00:34:48,433 --> 00:34:51,166
[ Singing continues ]

627
00:34:54,066 --> 00:34:56,533
In Darwin's theory
of sexual selection,

628
00:34:56,533 --> 00:34:59,566
males sing to attract females

629
00:34:59,566 --> 00:35:02,433
and females drive
the evolution of song

630
00:35:02,433 --> 00:35:06,666
by preferring
ever more complex songs.

631
00:35:06,666 --> 00:35:10,100
The females themselves
do not sing.

632
00:35:10,100 --> 00:35:13,266
Yet here we are listening
to a female lyrebird singing.

633
00:35:13,266 --> 00:35:16,533
[ Singing continues ]

634
00:35:16,533 --> 00:35:19,733
So, what is the function
of her song?

635
00:35:19,733 --> 00:35:22,866
[ Singing continues ]

636
00:35:22,866 --> 00:35:25,333
Well, the female raises
her chicks alone.

637
00:35:28,933 --> 00:35:31,800
The male plays no part.

638
00:35:31,800 --> 00:35:35,766
So it's extremely important for
her to maintain her territory

639
00:35:35,766 --> 00:35:38,466
and the food within it.

640
00:35:38,466 --> 00:35:42,733
She uses song to let everyone
know that it's her patch.

641
00:35:42,733 --> 00:35:45,066
[ Singing continues ]

642
00:35:48,200 --> 00:35:50,400
And Victoria is also researching

643
00:35:50,400 --> 00:35:54,033
whether song helps her
in other ways.

644
00:35:54,033 --> 00:35:55,800
In the last few years,

645
00:35:55,800 --> 00:35:59,566
she's been recording their songs
across the Blue Mountains.

646
00:35:59,566 --> 00:36:03,800
♪♪

647
00:36:03,800 --> 00:36:09,066
This is one of them --
a female mimicking a goshawk.

648
00:36:09,066 --> 00:36:11,566
[ Superb lyrebird
mimicking goshawk ]

649
00:36:15,433 --> 00:36:16,900
AUSTIN: It's very accurate.

650
00:36:16,900 --> 00:36:20,000
If you were play this call
alongside an actual goshawk,

651
00:36:20,000 --> 00:36:21,733
it would be very difficult
to tell the difference,

652
00:36:21,733 --> 00:36:24,166
if you were able
to tell the difference at all.

653
00:36:24,166 --> 00:36:26,366
ATTENBOROUGH:
So, what is the purpose

654
00:36:26,366 --> 00:36:30,700
of this perfect impersonation?

655
00:36:30,700 --> 00:36:33,866
She is using it to deceive
predators into thinking

656
00:36:33,866 --> 00:36:36,933
she's more dangerous
than she actually is.

657
00:36:36,933 --> 00:36:41,033
♪♪

658
00:36:41,033 --> 00:36:44,633
She is just as talented
as the more famous male.

659
00:36:44,633 --> 00:36:47,500
[ Superb lyrebird singing ]

660
00:36:47,500 --> 00:36:50,400
AUSTIN: So, the biggest purpose
of what we're doing

661
00:36:50,400 --> 00:36:52,266
working with
these female lyrebirds

662
00:36:52,266 --> 00:36:55,600
is to dispel this long-held myth

663
00:36:55,600 --> 00:36:57,766
that only recently was shown
not to be true,

664
00:36:57,766 --> 00:37:01,200
and that is the idea
that female birds don't sing

665
00:37:01,200 --> 00:37:02,833
or that it's very rare.

666
00:37:02,833 --> 00:37:04,700
And that's just simply
not the case.

667
00:37:04,700 --> 00:37:07,633
[ Birds singing ]

668
00:37:07,633 --> 00:37:12,800
ATTENBOROUGH: This surely
challenges Darwin's theory...

669
00:37:12,800 --> 00:37:15,900
as does my next,
revolutionary song.

670
00:37:15,900 --> 00:37:20,100
♪♪

671
00:37:20,100 --> 00:37:22,133
[ Superb fairy-wren singing ]

672
00:37:24,233 --> 00:37:29,400
My fifth song was also recorded
in Australia.

673
00:37:29,400 --> 00:37:32,900
It, too, like the song
of the female lyrebird,

674
00:37:32,900 --> 00:37:34,500
has rarely been heard.

675
00:37:34,500 --> 00:37:37,066
[ Superb fairy-wren singing ]

676
00:37:37,066 --> 00:37:39,600
It's important because
its existence

677
00:37:39,600 --> 00:37:43,866
changes our idea
of what song actually is.

678
00:37:43,866 --> 00:37:49,233
[ Superb fairy-wren singing ]

679
00:37:49,233 --> 00:37:51,600
This is a fairly common
Australian bird

680
00:37:51,600 --> 00:37:53,633
called a fairy-wren.

681
00:37:53,633 --> 00:37:58,000
[ Singing continues ]

682
00:37:58,000 --> 00:38:02,666
We filmed these birds for a BBC
series back in the 1990s.

683
00:38:02,666 --> 00:38:04,766
[ Superb fairy-wren singing ]

684
00:38:04,766 --> 00:38:06,666
♪♪

685
00:38:06,666 --> 00:38:11,600
We went there to film it because
it's extremely promiscuous.

686
00:38:11,600 --> 00:38:13,166
Both the male and female

687
00:38:13,166 --> 00:38:16,966
will mate
with many different partners.

688
00:38:16,966 --> 00:38:19,766
But what few people realized
at the time --

689
00:38:19,766 --> 00:38:21,633
and I certainly didn't --

690
00:38:21,633 --> 00:38:25,733
was that it's not just
the male that sings.

691
00:38:25,733 --> 00:38:27,833
♪♪

692
00:38:27,833 --> 00:38:29,900
The female does, too.

693
00:38:29,900 --> 00:38:33,966
[ Superb fairy-wren singing ]

694
00:38:33,966 --> 00:38:35,766
♪♪

695
00:38:35,766 --> 00:38:38,800
This is Canberra
Botanical Gardens.

696
00:38:38,800 --> 00:38:41,000
♪♪

697
00:38:41,000 --> 00:38:43,766
Professor Naomi Langmore
was the scientist

698
00:38:43,766 --> 00:38:47,533
who made
our fairy-wren recording.

699
00:38:47,533 --> 00:38:48,633
She was one of the first

700
00:38:48,633 --> 00:38:52,300
to realize
the significance of female song.

701
00:38:52,300 --> 00:38:56,066
[ Birds singing ]

702
00:38:56,066 --> 00:38:59,133
A male fairy-wren
with glorious iridescent blue

703
00:38:59,133 --> 00:39:02,100
and striking black plumage.

704
00:39:02,100 --> 00:39:03,966
Rather difficult to miss.

705
00:39:03,966 --> 00:39:06,500
[ Superb fairy-wren singing ]

706
00:39:06,500 --> 00:39:09,266
So, where is the female?

707
00:39:09,266 --> 00:39:12,233
Well, not at the top of a perch
like the male,

708
00:39:12,233 --> 00:39:15,533
but instead here,
hiding in the bushes.

709
00:39:15,533 --> 00:39:17,766
♪♪

710
00:39:17,766 --> 00:39:23,266
She is, comparatively,
rather dull -- a drab brown.

711
00:39:23,266 --> 00:39:25,500
LANGMORE: Because females
are often less flashy

712
00:39:25,500 --> 00:39:27,566
and eye-catching than males,

713
00:39:27,566 --> 00:39:30,100
it's very easy
to miss female song.

714
00:39:30,100 --> 00:39:32,400
[ Superb fairy-wren singing ]

715
00:39:32,400 --> 00:39:34,600
ATTENBOROUGH:
But sing she does.

716
00:39:34,600 --> 00:39:37,966
[ Singing continues ]

717
00:39:37,966 --> 00:39:41,466
Just as male song is used
in competition with other males,

718
00:39:41,466 --> 00:39:46,800
female song seems to be in
competition with other females.

719
00:39:46,800 --> 00:39:50,133
But why didn't we hear her
before now?

720
00:39:50,133 --> 00:39:54,433
Is it really just because she is
less noticeable than the male?

721
00:39:54,433 --> 00:39:56,700
LANGMORE: In the history
of the study of birdsong,

722
00:39:56,700 --> 00:39:59,166
most research was done
in the northern hemisphere,

723
00:39:59,166 --> 00:40:01,166
in Europe and North America,

724
00:40:01,166 --> 00:40:04,833
and in those regions, female
song is comparatively rare.

725
00:40:04,833 --> 00:40:08,133
And so researchers working
in those regions generalized

726
00:40:08,133 --> 00:40:10,533
from what they were observing
in their local birds

727
00:40:10,533 --> 00:40:14,800
and assumed that male song was
the norm throughout the world.

728
00:40:14,800 --> 00:40:17,266
ATTENBOROUGH:
A male-biased view of birdsong

729
00:40:17,266 --> 00:40:21,533
had, to an extent,
deafened us to female song.

730
00:40:21,533 --> 00:40:23,866
KREBS: So, when I was doing
my research,

731
00:40:23,866 --> 00:40:25,300
it was basically assumed

732
00:40:25,300 --> 00:40:27,533
that it's the male that sings

733
00:40:27,533 --> 00:40:29,233
and the female that doesn't.

734
00:40:29,233 --> 00:40:31,466
Maybe that's because most
of the scientists were males

735
00:40:31,466 --> 00:40:32,866
who were studying birdsong.

736
00:40:32,866 --> 00:40:34,833
LANGMORE: But now
there's a new generation

737
00:40:34,833 --> 00:40:36,900
of female scientists
coming through,

738
00:40:36,900 --> 00:40:39,100
studying birdsong
all around the world,

739
00:40:39,100 --> 00:40:42,800
and discovering that actually
female song is very common

740
00:40:42,800 --> 00:40:46,566
and occurs
in more species than not.

741
00:40:46,566 --> 00:40:48,366
ATTENBOROUGH:
And it's only now

742
00:40:48,366 --> 00:40:51,400
that they're properly
being heard.

743
00:40:51,400 --> 00:40:53,700
Naomi and her colleagues
have discovered

744
00:40:53,700 --> 00:41:00,033
that in 64% of all songbird
species, females sing.

745
00:41:00,033 --> 00:41:02,700
and that, in the distant past,

746
00:41:02,700 --> 00:41:05,200
the ancestors of all songbirds

747
00:41:05,200 --> 00:41:09,000
would have had both male 
and 

748
00:41:05,200 --> 00:41:09,000
female singers.

749
00:41:09,000 --> 00:41:13,000
♪♪

750
00:41:13,000 --> 00:41:18,133
When birdsong began,
perhaps all female birds sang.

751
00:41:18,133 --> 00:41:20,866
[ Birds singing ]

752
00:41:20,866 --> 00:41:25,733
So, why don't all female birds
sing today?

753
00:41:25,733 --> 00:41:29,300
The answer is migration.

754
00:41:29,300 --> 00:41:31,800
Male migrants,
like the nightingale,

755
00:41:31,800 --> 00:41:35,833
arrive in their breeding grounds
before the female.

756
00:41:35,833 --> 00:41:39,100
They set up and defend
the breeding territories,

757
00:41:39,100 --> 00:41:41,233
so the females
don't need to sing.

758
00:41:41,233 --> 00:41:43,866
♪♪

759
00:41:43,866 --> 00:41:45,633
In species that don't migrate,

760
00:41:45,633 --> 00:41:47,833
like the lyrebird
and the fairy-wren,

761
00:41:47,833 --> 00:41:52,466
then often the females
will have their own territory

762
00:41:52,466 --> 00:41:54,633
[ Bird singing ]

763
00:41:54,633 --> 00:41:57,166
And they will sing to defend it.

764
00:41:57,166 --> 00:42:00,366
[ Birds singing ]

765
00:42:00,366 --> 00:42:03,533
This female song
challenges the way scientists

766
00:42:03,533 --> 00:42:05,466
have thought about
sexual selection

767
00:42:05,466 --> 00:42:08,500
for the last hundred years.

768
00:42:08,500 --> 00:42:10,800
DALZIELL: This recent discovery
is a paradigm shift.

769
00:42:10,800 --> 00:42:12,900
It's extremely exciting.

770
00:42:12,900 --> 00:42:16,133
And it really forces us
again to reconsider

771
00:42:16,133 --> 00:42:18,633
what we think of as birdsong.

772
00:42:18,633 --> 00:42:20,500
[ Birds singing ]

773
00:42:20,500 --> 00:42:23,033
LANGMORE: Birdsong was
fundamental to the formulation

774
00:42:23,033 --> 00:42:26,066
of Darwin's theory
of sexual selection.

775
00:42:26,066 --> 00:42:28,400
And the discovery
that females sing as well

776
00:42:28,400 --> 00:42:32,400
makes us challenge that theory.

777
00:42:32,400 --> 00:42:34,833
ATTENBOROUGH: Because
our perception of birdsong

778
00:42:34,833 --> 00:42:38,266
has been biased
towards the northern hemisphere,

779
00:42:38,266 --> 00:42:40,200
we have been unaware

780
00:42:40,200 --> 00:42:44,400
of some of the most thrilling
birdsongs on the planet.

781
00:42:44,400 --> 00:42:46,766
But that view is changing.

782
00:42:46,766 --> 00:42:49,900
♪♪

783
00:42:49,900 --> 00:42:53,633
KREBS: Our understanding of song
is continually developing,

784
00:42:53,633 --> 00:42:56,100
and all the time
we're learning new things.

785
00:42:56,100 --> 00:43:00,600
It's a mystery that needs
real research to unravel it.

786
00:43:00,600 --> 00:43:02,333
And we're still learning.

787
00:43:02,333 --> 00:43:04,600
♪♪

788
00:43:04,600 --> 00:43:08,300
ATTENBOROUGH: How exciting it is
to think of the discoveries

789
00:43:08,300 --> 00:43:11,300
that are about
to be made about birdsong.

790
00:43:11,300 --> 00:43:14,700
♪♪

791
00:43:14,700 --> 00:43:17,900
[ Birds singing ]

792
00:43:17,900 --> 00:43:21,533
♪♪

793
00:43:21,533 --> 00:43:24,833
This next groundbreaking
recording reminds us

794
00:43:24,833 --> 00:43:27,900
just how thrilling those
new discoveries could be...

795
00:43:27,900 --> 00:43:30,333
♪♪

796
00:43:30,333 --> 00:43:31,966
...because it revealed to us

797
00:43:31,966 --> 00:43:34,666
an entirely
different world of song.

798
00:43:34,666 --> 00:43:38,966
♪♪

799
00:43:38,966 --> 00:43:42,266
Few animal songs
are more beautiful

800
00:43:42,266 --> 00:43:46,733
than the ones
that are recorded on this disc.

801
00:43:46,733 --> 00:43:51,100
And yet, had it not been for
recent technological advances,

802
00:43:51,100 --> 00:43:54,700
we would never have known
that such songs existed.

803
00:43:54,700 --> 00:43:57,466
♪♪

804
00:43:57,466 --> 00:44:01,166
The waters off the coast
of Bermuda.

805
00:44:01,166 --> 00:44:05,000
U.S. Navy engineers are using
underwater microphones,

806
00:44:05,000 --> 00:44:10,433
called hydrophones,
to listen for enemy submarines.

807
00:44:10,433 --> 00:44:12,666
This is what they pick up.

808
00:44:12,666 --> 00:44:18,000
[ Low humming ]

809
00:44:18,000 --> 00:44:19,400
It's not a submarine

810
00:44:19,400 --> 00:44:22,466
or, indeed, any kind
of man-made noise.

811
00:44:22,466 --> 00:44:26,200
[ Humming continues ]

812
00:44:26,200 --> 00:44:31,766
I'll always remember the first
time I heard those songs.

813
00:44:31,766 --> 00:44:35,133
It brought back to my mind
the stories of sailors

814
00:44:35,133 --> 00:44:37,066
in the old sailing ship days,

815
00:44:37,066 --> 00:44:40,200
out at sea in their bunks,
hearing these wonderful,

816
00:44:40,200 --> 00:44:44,566
eerie sounds resonating
through the ship.

817
00:44:44,566 --> 00:44:47,133
It didn't come, of course,
from a mermaid,

818
00:44:47,133 --> 00:44:50,300
but something perhaps
even more extraordinary --

819
00:44:50,300 --> 00:44:53,733
a gigantic creature,
weighing many tons --

820
00:44:53,733 --> 00:44:55,533
a whale.

821
00:44:55,533 --> 00:44:58,500
[ Humpback whale singing ]

822
00:45:02,733 --> 00:45:06,033
Almost unbelievably,
this was the first time

823
00:45:06,033 --> 00:45:11,800
that anyone had ever identified
the sound of the whale.

824
00:45:11,800 --> 00:45:17,533
When biologist Dr. Roger Payne
heard it, he was thrilled.

825
00:45:17,533 --> 00:45:20,233
PAYNE:
It was back in 1967, about,

826
00:45:20,233 --> 00:45:22,633
that I met a fellow
named Frank Watlington,

827
00:45:22,633 --> 00:45:24,566
who became a great friend.

828
00:45:24,566 --> 00:45:28,366
And he played a sound
to me of humpback whales.

829
00:45:28,366 --> 00:45:31,433
[ Humpback whale singing ]

830
00:45:31,433 --> 00:45:36,000
It was the most beautiful thing
I had ever heard from nature.

831
00:45:36,000 --> 00:45:39,133
[ Singing continues ]

832
00:45:44,600 --> 00:45:46,266
The first time
I ever went swimming

833
00:45:46,266 --> 00:45:49,033
with a whale that was singing,

834
00:45:49,033 --> 00:45:51,500
it was an incredible experience.

835
00:45:51,500 --> 00:45:54,500
It's completely shattering.

836
00:45:54,500 --> 00:45:57,133
[ Humpback whale singing ]

837
00:45:57,133 --> 00:45:59,600
It feels like,
when you get close to one,

838
00:45:59,600 --> 00:46:02,800
that something has put
its hands on your chest

839
00:46:02,800 --> 00:46:05,566
and is shaking you
until your teeth rattle.

840
00:46:05,566 --> 00:46:08,700
My first thought was,
"I wonder if I can stand this.

841
00:46:08,700 --> 00:46:11,733
I wonder if this is actually
gonna kill me somehow."

842
00:46:11,733 --> 00:46:16,200
[ Humpback whales singing ]

843
00:46:16,200 --> 00:46:18,200
ATTENBOROUGH:
The question was,

844
00:46:18,200 --> 00:46:20,966
would we call these sounds
"songs"?

845
00:46:23,433 --> 00:46:25,933
Some were short,
like bird calls,

846
00:46:25,933 --> 00:46:27,233
but others were longer,

847
00:46:27,233 --> 00:46:29,700
some up to half an hour.

848
00:46:29,700 --> 00:46:35,533
[ Humpback whale singing ]

849
00:46:35,533 --> 00:46:38,700
Speeded up, this is
what they sounded like.

850
00:46:38,700 --> 00:46:44,433
[ Rapid, high-pitched singing ]

851
00:46:44,433 --> 00:46:47,033
They sounded like birdsong.

852
00:46:47,033 --> 00:46:49,800
[ Singing continues ]

853
00:46:49,800 --> 00:46:52,200
Roger called them songs.

854
00:46:58,433 --> 00:47:00,400
In the late 1970s,

855
00:47:00,400 --> 00:47:03,566
I, too, went swimming
with humpback whales.

856
00:47:03,566 --> 00:47:05,900
[ Humpback whale singing ]

857
00:47:05,900 --> 00:47:07,866
I remember seeing this creature
below me

858
00:47:07,866 --> 00:47:10,466
and then hearing its song.

859
00:47:10,466 --> 00:47:15,466
[ Singing continues ]

860
00:47:15,466 --> 00:47:20,466
It was thought they sing
for the same reason as birds --

861
00:47:20,466 --> 00:47:25,766
males singing to rivals
and potential mates.

862
00:47:25,766 --> 00:47:29,400
But no one has ever seen
a female listening.

863
00:47:29,400 --> 00:47:31,733
[ Singing continues ]

864
00:47:31,733 --> 00:47:35,533
In truth, no one really knows
why whales sing.

865
00:47:35,533 --> 00:47:38,200
[ Singing continues ]

866
00:47:38,200 --> 00:47:40,000
But one thing is certain --

867
00:47:40,000 --> 00:47:43,633
the sound of their song
saved them from us.

868
00:47:43,633 --> 00:47:45,633
[ Singing continues ]

869
00:47:45,633 --> 00:47:48,966
In 1970, Roger released
an album called

870
00:47:48,966 --> 00:47:52,166
"Songs of the Humpback Whale."

871
00:47:52,166 --> 00:47:54,700
At the time,
we had been killing whales,

872
00:47:54,700 --> 00:47:57,866
mainly for their oil,
for centuries.

873
00:47:57,866 --> 00:48:01,700
[ Harpoon gun fires ]

874
00:48:01,700 --> 00:48:05,300
We were very close
to exterminating them

875
00:48:05,300 --> 00:48:08,066
out of sheer greed.

876
00:48:08,066 --> 00:48:10,366
Then we heard their song.

877
00:48:10,366 --> 00:48:14,600
[ Humpback whale singing ]

878
00:48:14,600 --> 00:48:17,700
PAYNE: Whole bunches of people
in several countries

879
00:48:17,700 --> 00:48:21,000
began making organizations
to save the whales,

880
00:48:21,000 --> 00:48:24,100
and the Save the Whales
movement was born.

881
00:48:24,100 --> 00:48:26,700
And in many ways, that was
sort of the beginning

882
00:48:26,700 --> 00:48:29,133
of the conservation movement.

883
00:48:29,133 --> 00:48:33,800
[ Singing continues ]

884
00:48:33,800 --> 00:48:36,300
ATTENBOROUGH: The conscience
of the world was awoken

885
00:48:36,300 --> 00:48:39,533
by this song of the whale.

886
00:48:39,533 --> 00:48:42,633
We heard it just in time
to save them.

887
00:48:42,633 --> 00:48:46,833
[ Singing continues ]

888
00:48:46,833 --> 00:48:49,900
But for my next
and final singer,

889
00:48:49,900 --> 00:48:51,833
there was no such reprieve.

890
00:48:53,633 --> 00:48:56,500
[ Kaua'i 'o'o singing ]

891
00:49:00,666 --> 00:49:04,700
There are few songs
more haunting than this.

892
00:49:07,933 --> 00:49:10,533
[ Kaua'i 'o'o singing ]

893
00:49:10,533 --> 00:49:16,066
It's a male Hawaiian 'o'o bird
calling for a mate.

894
00:49:16,066 --> 00:49:18,733
[ Singing continues ]

895
00:49:18,733 --> 00:49:21,166
But is he singing into silence?

896
00:49:21,166 --> 00:49:23,066
[ Singing continues ]

897
00:49:23,066 --> 00:49:27,100
Habitat destruction and the
introduction of invasive species

898
00:49:27,100 --> 00:49:30,333
have decimated
many Hawaiian songbirds,

899
00:49:30,333 --> 00:49:33,933
including the 'o'o.

900
00:49:33,933 --> 00:49:38,533
It may well be that by the time
this recording was made

901
00:49:38,533 --> 00:49:42,266
there were
no females left alive.

902
00:49:42,266 --> 00:49:44,866
It's the sound of a male

903
00:49:44,866 --> 00:49:47,366
singing for a mate

904
00:49:47,366 --> 00:49:50,766
who no longer exists.

905
00:49:50,766 --> 00:49:54,833
The 'o'o has since
been declared extinct.

906
00:49:54,833 --> 00:49:57,833
[ Kaua'i 'o'o singing ]

907
00:49:57,833 --> 00:50:00,633
He was the last
of an entire bird family

908
00:50:00,633 --> 00:50:03,200
found nowhere else on Earth,

909
00:50:03,200 --> 00:50:05,166
now gone.

910
00:50:05,166 --> 00:50:07,233
[ Singing continues ]

911
00:50:07,233 --> 00:50:11,100
There is no more dramatic
reminder of this loss

912
00:50:11,100 --> 00:50:13,433
than this sound.

913
00:50:13,433 --> 00:50:19,600
[ Singing continues ]

914
00:50:19,600 --> 00:50:24,800
♪♪

915
00:50:24,800 --> 00:50:27,333
And how many more songs
have we lost

916
00:50:27,333 --> 00:50:31,233
in other parts of the planet?

917
00:50:31,233 --> 00:50:35,333
Here in Britain, it's estimated
that 38 million birds

918
00:50:35,333 --> 00:50:39,600
have disappeared from our skies
in the last 60 years,

919
00:50:39,600 --> 00:50:42,300
one in five, gone.

920
00:50:42,300 --> 00:50:45,400
♪♪

921
00:50:45,400 --> 00:50:49,100
Climate change,
habitat deterioration,

922
00:50:49,100 --> 00:50:52,666
and the resulting decrease
in food and other resources

923
00:50:52,666 --> 00:50:54,466
are thought to be
the main factors

924
00:50:54,466 --> 00:50:58,766
behind this
catastrophic decline.

925
00:50:58,766 --> 00:51:02,400
It's now up to us to decide
how many more songs

926
00:51:02,400 --> 00:51:06,066
we will allow
to fade into silence.

927
00:51:06,066 --> 00:51:09,233
[ Birds singing ]

928
00:51:09,233 --> 00:51:14,933
♪♪

929
00:51:14,933 --> 00:51:18,466
These songs enrich
our lives, too.

930
00:51:18,466 --> 00:51:22,666
They are surely amongst
the loveliest in the universe,

931
00:51:22,666 --> 00:51:27,266
and without them our lives
would truly be impoverished.

932
00:51:27,266 --> 00:51:28,466
[ Singing continues ]

933
00:51:28,466 --> 00:51:32,033
And what is lost
when the songs fall silent

934
00:51:32,033 --> 00:51:35,566
is more than just
an enchanting operatic backdrop

935
00:51:35,566 --> 00:51:37,966
to our own lives --

936
00:51:37,966 --> 00:51:40,466
because, for the creatures
that sing them,

937
00:51:40,466 --> 00:51:44,800
songs are far more than that.

938
00:51:44,800 --> 00:51:47,400
They are a weapon of war,

939
00:51:47,400 --> 00:51:49,433
a serenade,

940
00:51:49,433 --> 00:51:51,466
a promise of parenthood,

941
00:51:51,466 --> 00:51:54,300
a daring deceit,

942
00:51:54,300 --> 00:51:57,433
or perhaps something even
more astonishing

943
00:51:57,433 --> 00:51:58,966
that we are yet to discover...

944
00:51:58,966 --> 00:52:01,133
[ Animals singing ]

945
00:52:01,133 --> 00:52:03,500
...each one a marvelous example

946
00:52:03,500 --> 00:52:05,966
of the spectacular
survival strategies

947
00:52:05,966 --> 00:52:07,733
that animals have developed

948
00:52:07,733 --> 00:52:09,433
in order to stay alive.

949
00:52:09,433 --> 00:52:11,300
[ Humpback whale singing ]

950
00:52:11,300 --> 00:52:14,066
That is why I'll never cease
to wonder

951
00:52:14,066 --> 00:52:17,500
at the beautiful sounds
we call song.

952
00:52:17,500 --> 00:52:19,500
♪♪

953
00:52:19,500 --> 00:52:23,500
[ Bird singing ]

954
00:52:26,100 --> 00:53:03,200
♪♪

955
00:53:03,200 --> 00:53:06,600
To learn more about what you've
seen on this "Nature" program,

956
00:53:06,600 --> 00:53:09,600
visit PBS.org.

957
00:53:09,600 --> 00:53:14,600
♪♪

958
00:53:16,100 --> 00:53:17,766
♪♪