Similar to how a cricket chirps by rubbing together sound-making apparatus in its wings, male club-winged manakins (Machaeropterus deliciosus ) use specially adapted feathers in each wing to make a tone, according to a Cornell University ornithologist in the July 29 issue of Science. The sound and how the bird produces it are unique among vertebrates.
"Essentially an instrument has evolved in this species, in this case a refined instrument," said Kimberly Bostwick, the paper's lead author, a curator in the birds and mammals division of Cornell's Museum of Vertebrates and a research associate in the Department of Ecology and Evolutionary Biology.
The club-winged manakin, found only in a strip of threatened cloud forest on the western slopes of the Andes Mountains along the extreme northwest corner of Ecuador extending into Colombia, has adapted its wings in this odd way due to sexual selection -- the sound makes the male more attractive to females of the species.
"In general, if an adaptation is really weird and out there, it is produced by sexual selection," said Bostwick, pointing out that peacock wings are another example of an adaptation due to sexual selection.
Darwin mentions the club-winged manakin in "The Descent of Man," his treatise on sexual selection and how characteristics that attract the opposite sex are passed down to the next generation. Darwin was fascinated that birds have vocal chords and sing, but he was particularly struck that some birds make noise with their bodies, Bostwick said. Although Darwin's book includes illustratio
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