Wave theory used to explain bird flocking behavior

New Scientist : Flocks of starlings in flight exhibit properties of sound waves. The resemblance arises through the propagation of information concerning changes in distance between individuals and in flying direction, according to a recent study . To better understand the physics involved, an international team of researchers created a three-dimensional model using data from real starling flocks. As they varied the size of the flock, the researchers found that the birds’ behavior also changed. Starlings appear to settle into either very large flocks of 10 000 or small flocks of 1000 or less. The larger flocks are much more flexible in shape because information about distance between individuals spreads relatively quickly, while information about flying direction does not. Therefore, one part may change direction, while another does not. In smaller flocks, direction information disseminates quickly across the entire group, which is then able to maintain a more rigid shape. Such collective behavior may exist in other animals as well and depends on the specific characteristics of the individuals involved.