ARI SHAPIRO, HOST:
Why do songbirds sing so much? Well, a new study suggests they have to to stay in shape. Here's NPR's Ari Daniel.
ARI DANIEL, BYLINE: A few years ago, I was out at dawn in South Carolina low country, a mix of swamp and trees draped in Spanish moss.
(SOUNDBITE OF BIRDS CHIRPING)
DANIEL: The sound of birdsong filled the air. It's the same in lots of places. Once the light of day switches on, songbirds launch their serenade.
IRIS ADAM: I mean, why birds sing is relatively well-answered.
DANIEL: Iris Adam is a behavioral neuroscientist at the University of Southern Denmark.
ADAM: For many songbirds, males sing to impress a female and attract them as mate. And also, birds sing to defend their territory.
DANIEL: But Adam says these reasons don't explain why songbirds sing so darn much.
ADAM: There's an insane drive to sing.
DANIEL: For some, it's hours every day. That's a lot of energy. Plus, singing can be dangerous.
ADAM: As soon as you sing, you reveal yourself - like, where you are, that you even exist, where your territory is. All of that immediately is out in the open for predators, for everybody.
DANIEL: Why take that risk? Adam wondered whether the answer might lie in the muscles that produce birdsong and if those muscles require regular exercise. So she designed a series of experiments on zebra finches, little Australian songbirds with striped heads and a bloom of orange on their cheeks. One of Adam's first experiments involved taking males and severing the connection between their brains and their singing muscles.
ADAM: Already after two days, they had lost some of their performance. And after three weeks, they were back to the same level when they were juveniles and never had sung before.
DANIEL: Next, she left the finches intact but prevented them from singing for a week by keeping them in the dark almost around the clock.
ADAM: The first two or three days, it's quite easy. But the longer the experiment goes, the more they are like, I need to sing. And so then you need to tell them, like, stop. You can't sing.
DANIEL: After a week, the birds' singing muscles lost half their strength. But does that impact what the resulting song sounds like? Here's a male before the seven days of darkness.
(SOUNDBITE OF BIRD CHIRPING)
DANIEL: And here he is after.
(SOUNDBITE OF BIRD CHIRPING)
ADAM: And I don't hear a difference.
DANIEL: It doesn't matter, though, if we can hear the difference. It matters if the females can because they're the ones the males are trying to impress. And six of the nine females preferred the song that came from a male who'd been using his singing muscles daily. Adam's conclusion...
ADAM: Songbirds need to exercise their vocal muscles to produce top-performance song. If they don't sing, they lose performance. Their vocalizations get less attractive to females, and that's bad.
DANIEL: This may help explain songbirds' incessant singing, a kind of daily vocal calisthenics to keep their instruments in tip-top shape. The research appears in the journal Nature Communications.
ANA AMADOR: It's significant because not many groups are studying in such detail the muscles.
DANIEL: Ana Amador is a neuroscientist at the University of Buenos Aires. She calls the study impressive.
AMADOR: What they are highlighting is that you need a lot of practice to achieve mastery in what you're doing.
DANIEL: And the findings may have something to say about human voices. Iris Adam again.
ADAM: If you apply the bird results to the humans, any time you stop speaking, for whatever reason, you might experience a loss in vocal performance.
DANIEL: Just take a singer who's recovering from a cold or someone who's had vocal surgery and might need a little rehab. Adam says one day, songbirds could help us improve how we train and restore our own voices, too. Ari Daniel, NPR News.
(SOUNDBITE OF MICHAEL JACKSON SONG, "ROCKIN' ROBIN") Transcript provided by NPR, Copyright NPR.
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