While birding along the shore of Whidbey Island this weekend, I watched a flock of perhaps 200 Starlings wheeling nearby in the sky. I understand some of the mechanisms of murmurations, wherein the birds closely track the movements of their neighbors. This time, I also noticed that the whole flock alternates between flapping wings and gliding. There would be several seconds of flying while actively flapping wings, followed by perhaps a one second rest time where ALL the birds would stop flapping their wings and glide, followed by another session of active flapping, then gliding, and so on. They all, virtually instantaneously, would switch between active and gliding modes. It's like an aerial ballet.

Lee Rentz
lee at leerentz.com
Shelton, WA