a hummingbird who beeps with his feathers

a hummingbird, so small, such a tiny anatomy, how could it send out anything but a soft & quiet sound . . . the exception, the male anna's hummingbird, which researchers have just determined produces a loud chirp with its unusually shaped tail feathers. the sound fills the western american skies during the mating season, as they dive from heights of 100 feet or more spreading their tapered, narrow-tipped outer tail feathers at the swoop's depth. in that moment, the feathers act like a clarinet reed, with the wind singing the single note. the frequency of the sound is nearly four octaves above middle c, the highest key on the piano, and has been expressed by observers to the flight like a beep, chirp, or whistle.