Songbirds sing with superfast muscles
Vocal muscles which can contract 100 times in the blink of an eye are the key to the songbirds dawn chorus, researchers have found.
Biologists measured vocal muscle activity in freely singing birds and made laboratory measurements of isolated muscles.
They found songbirds can contract and relax their vocal muscles in 3 to 4 milliseconds, which is 100 times faster than the 300 milliseconds to 400 milliseconds it takes for humans to blink an eye.
The birds’ vocal muscles change the position and stiffness of these folds to alter the volume and frequency of the sound.
“We discovered that the European starling and the zebrafinch control their songs with the fastest-contracting muscle type yet described,” says Dr Coen Elemans, a postdoctoral researcher in biology at the University of Utah.
“By having these extraordinary muscles, birds have a more precise control of their voice and can actively change the volume and frequency of their song faster than previously thought physically possible,” Elemans added.
“Superfast muscles were previously known only from the sound-producing organs of rattlesnakes, several fish and the ringdove.
“We now have shown that songbirds also evolved this extreme performance muscle type, suggesting these muscles – once thought extraordinary – are more common than previously believed.”
The findings are published in the Public Library of Science’s online journal PLoS ONE.
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