How do flocking birds move in unison?

Flocking birds – a starling murmuration – swooping in unison. Predators, such as peregrine falcons, have a hard time targeting one bird in an undulating flock of thousands.

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Flocking birds move together

We’ve all seen flocks of birds wheeling and swooping in unison, as if choreographed. How do they do this? Zoologists say they aren’t simply following a leader or their neighbors. If they were, the reaction time of each bird would need to be very fast. In fact, it would have to be faster than birds can react, according to scientists who’ve studied the reaction times of individual birds in laboratory settings. In 1984, zoologist Wayne Potts published what’s now the classic research on how flocking birds move in unison. His paper appeared in the journal Nature and showed that birds in flocks don’t just follow a leader or their neighbors. Instead, they anticipate sudden changes in the flock’s direction of motion.

And, he said, once a change in direction begins in the flock, it then spreads through the flock in a wave.

The propagation of this maneuver wave, as he called it, begins relatively slowly but can reach speeds three times faster than would be possible if birds were simply reacting to their immediate neighbors. Potts called this ability among flocking birds the chorus line hypothesis. That is, birds are like dancers who see an approaching leg kick when it’s still down the line, and anticipate what to do. He said:

These propagation speeds appear to be achieved in much the same way as they are in a human chorus line: individuals observe the approaching maneuver wave and time their own execution to coincide with its arrival.

Crowd watches starling murmuration in Tewkesbury, England

The gif below is from Giphy, via Storyful. Giphy wrote:

People gathered in a town in Gloucestershire, England, to watch starling murmurations … Tewkesbury became a hotspot for murmurations in January, according to the BBC. Local media said residents reported several large murmurations, which prompted people to travel to the area. Wendy Turbull, who captured this video, said she traveled from Birmingham with the hope of seeing the starlings take flight. Image via Wendy Turbull via Storyful.

Photographing the flock

Potts used high-speed film – and a frame-by-frame analysis – of flocks of red-backed sandpipers (Calidris alpina) to conduct his study. He found that the flock typically responded only to birds that banked into the flock, rather than away from it.

That makes sense, since flocking among birds serves the purpose of protecting birds from predators. (Although there are other purposes as well; for example, when one bird finds food, others in a flock eat, too.) Individual birds, those who are separated from the flock, are more likely to be picked off by predators.

Photos from our community

View larger. | Conor Ledwith Photography captured this flock of starlings - otherwise known as a murmuration - in December 2013. The bright object in the sky is Venus. Visit Conor Ledwith on Facebook.
View larger. | Conor Ledwith Photography captured this starling murmuration, with bright Venus, in the day’s last light on December 13, 2013. The bright object in the sky is the planet Venus. Visit Conor Ledwith on Facebook.
Long, nearly vertical line of about 40 flocking birds in blue sky with moon visible.
View at EarthSky Community Photos. | Kat Goldwarg in Niagara Falls, Ontario, Canada, captured this image on April 22, 2021. Kat wrote: “I was taking pictures of the moon at sunset after days of cold weather and cloudy skies. The sky was clearing and as the sunset glow was kissing the clouds, 3 flocks of birds passed. Here’s a look at one of them.” Thank you, Kat!
Flock of birds at sunset.
View at EarthSky Community Photos. | Patrice Sanders in Sequim, Washington caught this peaceful photo on June 27, 2023, and wrote: “Starling murmuration at sunset, taken off my front deck.” Thanks, Patrice!

Bottom line: According to Wayne Potts, a zoologist who published in the journal Nature in 1984, birds in flocks are able to change direction quickly not because they are following a leader or their neighbors. They can maneuver quickly because they see a movement far down the line and anticipate what to do next. Potts called this the chorus-line hypothesis for bird movement.

Want more about flocking birds? Read this article from

April 30, 2023

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Deborah Byrd

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