In a clip from their new series Super Powered Owls, a BBC Earth team set up a fascinating experiment to show the silent graceful flight of a barn owl. The team also gauged the noise and turbulence level of a pigeon and a peregrine falcon in comparison.
When air moves, it creates sound. The more movement, the greater the sound. The pigeon’s large body and small wings mean it can’t stay airborne without a lot of fast flapping. This creates turbulence in the feathers below. The peregrine has much larger wings, which it uses to build up speed to chase down its prey. The barn owl is far more graceful. …large wings and small body make it easy for her to generate lift. So one gentle wing beat sees her gliding effortlessly through the air.