The seventh starling

Last November, a series of Contrarian posts depicted the mesmerizing spectacle of starling murmuration: the undulating patterns made by starling flocks in flight (here, here, and here). Beyond their intrinsic beauty, these scenes provoke a sense of wonder: how do they do it? How do the hundreds of individuals who make up a flock of birds (or a school of sardines, or a swarm of midges) know how to execute their particular roles in the collective ballet. The standard explanation, recounted by a pair of Italian physicists who have studied the question [PDF], runs like this: [T]his collective behaviour stems from some simple rules...