Display Dive of Anna's Hummingbird (image) University of California - Berkeley Caption A male Anna's hummingbird caught during a display dive, compiled from high speed video. At the bottom of the dive, the bird flares its tail for 60 milliseconds. The inner vanes of the bird's two outer tail feathers vibrate in the 50 mph airstream to produce a brief chirp. Credit Christopher J. Clark and Teresa Feo/UC Berkeley Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.