Why do flocks of birds in flight seem to turn simultaneously?

Question

This phenomenon is similar in schools of fish. How do fish and birds "know" when to turn? Who to follow (if in fact they follow anyone)?

Answer 1

The highly coordinated movements of flocks of birds or schools of fish are among the most fascinating phenomena to be found in nature. The group seems to turn and maneuver as a single unit, changing direction almost instantaneously, leading some researchers to hypothesize that electromagnetic communication or even "thought transference" must be involved. In reality this behavior results from far less mysterious causes. Such movements are a prime example of emergent behavior: the behavior is not a property of any individual bird, but rather emerges as a property of the group itself. There is no leader, no overall control; instead the flock's movements are determined by the moment-by-moment decisions of individual birds, following simple rules in response to interactions with their neighbors in the flock.

Answer 2

The schooling of fish and the flocking of birds can be simulated on a computer with two very easy rules and that is what the birds/fish are doing.
1. Fly or swim away from a predator
2. If the animal next to you turns, turn the same way.

They will have a general direction of travel which is maintained but the sudden changes are from following the two rules.

Answer 3

Latest research shows that flocks of birds and schools of fish fly in peculiar formations by imitating their immediate neighbours. Thus the movement of one organism influences that of the entire group. This has been studied using mathematics biology.

Answer 4

I always laugh when people think up elaborate explanations to explain this sort of thing. I always thought it was because they were all experiencing the same stimulus.
Think about it... they are all quite close together so they would be experiencing similar wind currents. They all react in the same way to the same type of stimuli. That and the fact that they can see their neighbour start to turn, and that just acts as an additional stimulus.