... and reproduction in any medium provided that the original work is properly attributed. Summary: Experimentally rubbing isolated feathers together shows that the velvet on owl feathers substantially diminishes the sound of feathers rubbing against neighboring feathers. Aeroacoustics Quiet flight...

... and confirm that they collide over the back of the bird at the moment (±1 ms) the wingsnap is produced. Using aeroacoustic theory, we quantitatively estimate the acoustic signatures from several sonation mechanisms. We conclude that only the physical contact hypothesis, wherein the wing collisions create...