Finch: Bird Song Mechanics

music
ambience: Finch call

For years, scientists have been trying to figure out how birds produce there unique sounds. Recent findings have given us some new clues. I’m Jim Metzner, and this is the Pulse of the Planet. Jeff Podos is an assistant professor of biology at the University of Massachusetts, in Amherst. He says that the birds’ musical sound is a result of a number of factors, including the way it uses its beak.

“This is a Darwin’s finch singing from a branch in the field. Let’s listen first to the sound of the song produced by this large tree finch. This bird is repeating two notes. The first note is a low frequency sound. And it follows that with a second sound that’s higher frequency. And we can also play that sound in slow motion at slower speed and it becomes even more obvious that there are two notes, low frequency and high frequency.

“Now during the song, the bird is doing different things with its beak. During the production of the low frequency sound the first note the bird has its beak fairly closed and its head stretched forward. We compare that then to what the bird is doing as it’s producing the second note. As it finishes the first note and it gets into the second note it opens its beak fairly widely and pulls its head back and the effect of that is to shorten the length of the vocal tract. The vocal tract consists of the trachea together with the beak they form a resonance chamber through which the sounds produced will pass. Now the vocal tract we know plays a very important role in song production in birds, acting as anacoustic resonance filter. It filters out harmonic overtones, noise in the signal and it allows birds to produce the sounds that are very characteristic of songbirds, these sweet sounding, very musical sorts of sounds.”

Pulse of the Planet is presented with support provided by the National Science Foundation. I’m Jim Metzner.

music

Finch: Bird Song Mechanics

How do beaks and body movement contribute to the sweet musical notes of a birdsong?
Air Date:08/05/2002
Scientist:
Transcript:


music
ambience: Finch call

For years, scientists have been trying to figure out how birds produce there unique sounds. Recent findings have given us some new clues. I'm Jim Metzner, and this is the Pulse of the Planet. Jeff Podos is an assistant professor of biology at the University of Massachusetts, in Amherst. He says that the birds' musical sound is a result of a number of factors, including the way it uses its beak.

"This is a Darwin’s finch singing from a branch in the field. Let’s listen first to the sound of the song produced by this large tree finch. This bird is repeating two notes. The first note is a low frequency sound. And it follows that with a second sound that’s higher frequency. And we can also play that sound in slow motion at slower speed and it becomes even more obvious that there are two notes, low frequency and high frequency.

"Now during the song, the bird is doing different things with its beak. During the production of the low frequency sound the first note the bird has its beak fairly closed and its head stretched forward. We compare that then to what the bird is doing as it's producing the second note. As it finishes the first note and it gets into the second note it opens its beak fairly widely and pulls its head back and the effect of that is to shorten the length of the vocal tract. The vocal tract consists of the trachea together with the beak they form a resonance chamber through which the sounds produced will pass. Now the vocal tract we know plays a very important role in song production in birds, acting as anacoustic resonance filter. It filters out harmonic overtones, noise in the signal and it allows birds to produce the sounds that are very characteristic of songbirds, these sweet sounding, very musical sorts of sounds."

Pulse of the Planet is presented with support provided by the National Science Foundation. I'm Jim Metzner.

music