music: Finch song
Anyone who’s ever listened to one of Shakespeare’s plays knows that human language evolves over time. Well, it turns out bird song does too. 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 who studies birdsong.
“There are random changes in songbird songs. So birds learn their songs and sometimes they’re not so good at learning. And so over many generations, slight errors can accumulate, much like the game of telephone where you start with one signal and then over many iterations, it becomes different. Another common explanation is that when birds move to new habitats, they’re actually encountering different acoustic environments. So, for example, an ancestral population might live in an arid area, with a lot of wind noise or a lot of surf noise, but then if they move to an environment that is a forest , that will present a really different acoustic environment through which other strategies for producing sound are going to be more effective.”
Now Jeff Podos is suggesting there is yet another mechanism for changes in bird song: beak size. It’s long been known that birds’ beaks evolve as their feeding habitat changes. But no one is looked at how that affects a bird’s song, or mode of communication. Podos’ work suggests that as birds beaks change in response to new feeding environments, it effects the sound of the song. And even the slightest change in, say a male’s mating call, can cause a female to ignore him.
“They would say, ‘I know the song of my population that will help me identify an appropriate male, now I hear this other song and it sounds kind of different and that’s different. Well maybe because it’s from a different population, so, I’m not going to mate.'”
We’ll hear more about how changing songs effect the evolution of bird species in future programs.
Pulse of the Planet is presented with support provided by the National Science Foundation. I’m Jim Metzner.
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