The Humming of the Hummingbird

A Physics study at Stanford University has solved why Hummingbirds hum (https://www.theguardian.com/science/2021/mar/16/scientists-unlock-secret-of-why-hummingbirds-hum). Somewhat predictably, the hum is produced by the bird's unusual hovering, flight pattern. Unlike other birds, hummingbirds generate lift on both the up- and the down-strokes of their wings. Hummingbirds also beat their wings much faster than other species. It's the pressure changes produced by the wing movements, generating the distinctive hum!