Change the number of starlings:

Flocking starlings

This model is based on ideas from Wikipedia. The 'starlings' try to move in the same direction as their five nearest neighbours; and they keep a certain distance away from each other. In this model, they also slightly change velocity randomly each iteration; are constrained in an ellipsoidal 3-D space; and attempt to fly at a constant speed, bouncing off the ellipsoidal boundary if they hit it.