Chorus Line in the Sky

BirdNote^®

Chorus Line in the Sky

Written by Dennis Paulson

This is BirdNote!
[Chattering of Dunlin flock]
What is that cloud low in the autumn sky, shape-shifting as you watch from a beach or mudflat, suddenly flashing from dark to light? It’s a cloud of small sandpipers called Dunlins. [Chattering of Dunlin flock] When threatened by a falcon, for instance, Dunlins take to the air, flying so close together that it’s hard for a predator to capture one. The Dunlins’ synchronous twisting-and-turning is a marvel of aerial acrobatics, with the birds alternately flashing brown backs and white bellies. The speed of change is breathtaking, with hundreds of birds turning simultaneously.
[Chattering of Dunlin flock] A researcher, curious about the lack of midair collisions – and speculating about extrasensory communication – filmed a few of these flocks. He found that a bird at one edge turns toward the middle, and a wave sweeps across the entire flock in less than a second. Like a member of a chorus-line, each bird sees the movement beginning to happen and makes the appropriate response.
[Chattering of Dunlin flock]
To see that chorus-line of Dunlin, begin at our website, BirdNote.org. Also sign up for the podcast or weekly preview email. That’s BirdNote.org. I’m Mary McCann.
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Bird sounds provided by The Macaulay Library at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by W.W. H. Gunn.
Western Sandpiper in flight recorded and provided by Martyn Stewart, Naturesound.org.
Producer: John Kessler
Executive Producer: Chris Peterson
© 2014 Tune In to Nature.org      October 2016     Narrator: Mary McCann
ID# 102706DUNLKPLU      flight-05b    

http://www.youtube.com/watch?v=j7YZ3XzQ3pk
Wayne Potts, now at U. of Utah.  Potts, W.K. 1984. The chorus line hypothesis of maneuver coordination in avian flocks. Nature 309:344-345.