There’s more subtlety than humans have realized in dropping out of the sky so fast your tail feathers sing.
Male Costa’s hummingbirds in western North America are masters of the tail-screaming courtship plunge. Acoustic cameras recorded these repeated stunts and revealed that, as the male whooshes down, he twists half of his tail sideways, says ornithologist Christopher J. Clark of the University of California, Riverside. That twist aims the prolonged feather whistle toward the female he’s swooping by, Clark and his colleague Emily Mistick of the University of British Colombia in Vancouver report April 12 in Current Biology.
The recordings, which use microphone arrays to localize a sound on video, shed light on another quirk of Calypte costae’s performance. While male hummingbirds of other species swoop over the female during courtship dives, the