Flash steering simulation, which includes character movement behaviors from Craig Reynold's Steering Behaviors paper. This includes Unaligned Collision Avoidance between bird flocks. and Obstacle Avoidance and Containment with the fish. I also added a touch where when the fish jump out of the water, a flock of birds dives down at them.
If you hit space while "playing" the video, you can see the vector's I drew using Flash's Drawing API to debug the forward vectors, a circle around the individual flocks, and a line that shows when flocks are going to collide.