Organized flight in birds

The organized flight of birds is one of the most easily observed, yet challenging to study, phenomena in biology. Birds that fly in organized groups generally do so in one of two fashions: Line formations and Cluster formations. The former groups are typical of large birds such as waterfowl, where birds fly arranged in single lines, often joined together. The scientific questions about these groups usually involve potential adaptive functions, such as why geese fly in a V. Cluster formations are typically made up of large numbers of smaller birds such as pigeons or starlings flying in more irregular arrangements that have a strong three-dimensional character. The groups are defined by synchronized and apparently simultaneous rapid changes in direction. Scientific questions about these groups are usually concerned with mechanism such as how synchrony is achieved. Although field observations about the phenomenon date to the origins of natural history, experimental studies did not begin until the 1970s. Early experimenters and theoreticians were primarily biologists, but more recently aeronautical engineers, mathematicians, computer scientists and, currently, physicists have been attracted to the study of organized flight. Computer modelling has recently generated striking visual representations of organized flight and a number of hypotheses about its functions and mechanisms, but the ability to test these hypotheses lags behind the capacity to generate them. We suggest that a multi disciplinary approach to the phenomenon will be necessary to resolve apparently conflicting current hypotheses.