There’s lots more to bird feathers than just keeping birds warm and waterproof and making them look pretty.
“The Anna’s hummingbird chirps with its tail: a new mechanism of sonation in birds,” was recently published by Christopher Clark and Teresa Feo from UC Berkeley.
Basically, when the male Anna’s hummingbird is in the middle of its dramatic courtship display — in a 100-foot high-speed dive, straight down — it makes a series of chirps to help attract female Anna’s hummingbirds. (As if those amazing dives aren’t enough!)
It was once thought that those sounds were vocal, but this study now appears to show that the sounds are made when wind passes across the edges of certain feathers. It makes them buzz rapidly when the male hummingbird spreads his tail as he pulls up at the bottom of his dive. It’s kind of like when a kid holds a leaf between his fingers and blows across it to produce a loud SQUEAK!
For the whole story see: http://www.berkeley.edu/news/media/releases/2008/01/30_hummingbird.shtml
DOVES DO IT, TOO:
The squeaky sound mourning doves make when they take off is produced the same way when wind passes over special feathers on the doves’ wings. The faster the doves flap their wings, the higher the pitch of the squeaks.
OWLS ARE DIFFERENT:
Interestingly, owls use their feathers for the exact opposite action — to NOT make any sounds.
Since they hunt at night when it’s dark, owls have to be sneaky hunters. To help them, owl feathers have soft, fringed edges, as opposed to daytime birds whose feathers have hard edges. The fringed (fuzzy) owl feathers muffle the sounds of the air as it passes over them when the owl is flying.
Nothing can hear an owl when it’s flying, not even a mouse. Too bad for the mouse.
Mother Nature is one very clever lady, don’t you think? /Gary