If you are a bird lover, you may have marveled at how great flocks of starlings move in unison. There are several excellent examples on YouTube, like this one: https://www.youtube.com/watch?v=eakKfY5aHmY . So how do they do it?
Science has been wondering the same thing. It’s only been recently that we’ve had the tools to observe what exactly is going on. Basically, each bird is reacting to the birds nearest it. Any change in movement is copied by a bird’s seven closed neighbors, then by their seven closest neighbors, and so on until the flock is following along. The maneuver scales up beautifully, so huge flocks end up moving virtually as one.
Why seven? It’s the number that seems to work best, striking a good balance between group cohesiveness and the individual.
How does this cohesive movement help the flock? There is safety in numbers. If a predator, such as a peregrine falcon, dives on the flock and everyone moves in unison, it becomes much tougher to pick off one bird. Conversely, if the predator is successful, that eliminates one member of the species who hasn’t figured out the system from the gene pool. In this case, it’s win-win.
The phenomenon is called mumuration, and if you’re a scientist, you can wax poetic about “scale-free correlation” and “synchronized orientation.” The rest of us can simply enjoy the videos.
To know more, read “The Incredible Science Behind Starling Mumurations” by Jaymi Heimbuch at https://www.mnn.com/earth-matters/animals/stories/the-incredible-science-behind-starling-murmurations .