Finch: Beaks Big and Small

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ambience: Finch bird sounds, small tree finch sounds, warbler song, sound of large ground finch

We’re listening to finches recorded on the Galapagos Islands. I’m Jim Metzner, and this is the Pulse of the Planet. Darwin and other scientists studied the variety and the shape of these birds’ beaks. Some have larger beaks for cracking seeds, and others have smaller ones for catching insects. Well now Jeffrey Podos an assistant professor of biology at the University of Massachusetts, in Amherst is asking if the difference in beak size could affect the birds’ songs as well.

“So if we take a look at the tree finches — let’s take a listen to the small tree finch. That bird has a beak that’s really adapted for eating insects, — that’s not having the requirement of crushing seeds at all, it’s not a seed eater, and so its musical instrument, at least the beak part is more freed up to be more versatile and thus it’s able to produce songs that are more rapid. Another very impressive singer among the Darwin’s finches is the warbler finch, which is the smallest beak and again it’s adapted for eating insects. And that song is complex, not so much in rates of repetition, but in the range of frequencies reproduced — and that translates as we listen to it into the richness and complexity of the sound. So it’s sweeping through a wide range of frequencies.”

But unlike the insect eating smaller finches, the ground finches are seed eaters with larger beaks.

“This will be the song of a large ground finch. Now if you can hear that the song is fairly slow, it has a buzzy quality, and fairly slow and it’s not very complex. “

It turns out that female finches may be indirectly favoring certain beak sizes in their mates as they listen and are attracted to the calls of male birds. We’ll hear more about that in future programs. Pulse of the Planet is presented with support provided by the National Science Foundation.

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Finch: Beaks Big and Small

The complexity of a finch's song is determined by the size of its beak.
Air Date:08/12/2002
Scientist:
Transcript:


music
ambience: Finch bird sounds, small tree finch sounds, warbler song, sound of large ground finch

We're listening to finches recorded on the Galapagos Islands. I'm Jim Metzner, and this is the Pulse of the Planet. Darwin and other scientists studied the variety and the shape of these birds' beaks. Some have larger beaks for cracking seeds, and others have smaller ones for catching insects. Well now Jeffrey Podos an assistant professor of biology at the University of Massachusetts, in Amherst is asking if the difference in beak size could affect the birds' songs as well.

"So if we take a look at the tree finches -- let’s take a listen to the small tree finch. That bird has a beak that’s really adapted for eating insects, -- that’s not having the requirement of crushing seeds at all, it’s not a seed eater, and so its musical instrument, at least the beak part is more freed up to be more versatile and thus it's able to produce songs that are more rapid. Another very impressive singer among the Darwin’s finches is the warbler finch, which is the smallest beak and again it’s adapted for eating insects. And that song is complex, not so much in rates of repetition, but in the range of frequencies reproduced -- and that translates as we listen to it into the richness and complexity of the sound. So it’s sweeping through a wide range of frequencies."

But unlike the insect eating smaller finches, the ground finches are seed eaters with larger beaks.

"This will be the song of a large ground finch. Now if you can hear that the song is fairly slow, it has a buzzy quality, and fairly slow and it’s not very complex. "

It turns out that female finches may be indirectly favoring certain beak sizes in their mates as they listen and are attracted to the calls of male birds. We'll hear more about that in future programs. Pulse of the Planet is presented with support provided by the National Science Foundation.

music