Club-winged manakin
The manakins are a family of some sixty small passerine bird species of subtropical and tropical Central and South America.
The Club-winged Manakin, Machaeropterus deliciosus, Family: Pipridae, produces a unique mechanical sound with their extremely modified secondary feathers. "Scientists have discovered that a colourful, South American sparrow-like bird uses a [...] technique to woo its potential partners" similar to "romantically inclined males [serenading] loved ones with the strains of a violin" Telegraph. Its wings produce tones at a frequency of around 1,400 cycles a second - about 14 times faster than it shakes its wings (faster wing movement than hummingbirds) according to a Cornell University ornithologist in the July 29 issue of Science. "[E]ach time a manakin shook its wings, its tip rakes across the ridges of the neighboring feather like a spoon moving across a washboard. Each time it hit a ridge, the tip produced a sound. The tip would strike each ridge twice - once as the feathers collided and once as they moved apart again. Dr. Bostwick realized that this raking movement allowed a wing to produce 14 sounds during each shake. As a result, a bird could shaking its wings 100 times a second could produce a sound with a frequency of 1,400 cycles a second." New York times
"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." Biology News