One cold morning last week, as I was out to pick up our newspapers, a group of perhaps 250 starlings took off from a neighbor's trees, rose as a mass, wheeled a couple of circles in the air over the trees and settled in other trees nearby. There were no predators in evidence, so iIt was not clear what made them fly or how they decided when and where to land. Lots of what we understand about this cooperative behavior has resulted from the fact that an astonishingly simple computer model does a very good job of mimicking it. The computer routine called "boids" can be run in Java within your browser (see http://www.red3d.com/cwr/boids/) . Brian Hayes' current "Computing Science" column in American Scientist updates the status of this aspect of avian behavior, including the work of Ballerini et al. (what an appropriate name for this work!), who has been analyzing the flights of bird flocks using computer analysis of 3-D photographs. Some of the original ideas seem to be holding up - that flocks are held together by local interactions - but the shapes of the assemblages is not as globular as they appear to the observer, who has a kind of 2-D view. There is a lot more to learn, and amateur scientists may be able to contribute to this field.