Recently, researchers used mathematics and technology to discover how knowledge and movement transfer across a starling flock.
Since the 1930s, proposed explanations for how starlings move in unison have ranged from telepathy to copying neighboring birds’ directional changes to maintain a certain distance between them. Recently, researchers from Italy, Argentina and the US used mathematics and technology to discover how knowledge and movement transfer across the flock.
Using high-speed cameras, researchers from Italy's Institute for Complex Systems filmed starlings in Rome, where one flock can contain thousands of birds. Tracking software then enabled them to see when and where each bird turned and how the turns’ sharpness cascades through the flock.
Results showed a group of 400 birds requires only half a second to turn. A leader team of a few birds flying close together initiated turns while other flock members rotated in and out of the group.
According to Science magazine, researchers "derived a mathematical description of how a turn moves through the flock. They assumed each bird had a property called spin, similar to the spins of elementary particles in physics. By matching one another's spin, the birds conserved the total spin of the flock. As a result of that conservation, the equations showed that the information telling birds to change direction travels through the flock at a constant speed."
Team co-lead Andrea Cavagna compares the behavior mathematically to superfluid helium, emphasizing that many physical systems share principles of math and physics.