Birds in a flock, like the Starlings above, sometimes move together as if connected by invisible threads. Scientists have found that a few simple rules can explain apparently complex flocking behavior.
The most famous flocking model, shown diagrammatically below, is known as Boids.
This model requires each member of the flock to act based on visual cues as follows:
1) Separation : Give neighbors enough space to fly
2) Alignment: Steer in the same average direction as surrounding neighbors
3) Cohesion: Fly towards the average position of surrounding neighbors as long as rule 1 has been satisfied.
These rules have been used to generate life-like bird flocks in animated movies such as Batman Returns. Flocking does not need one overall leader — in contrast to the leader of a line of birds who are using upwash to save energy (see “Formation Flying”).
LEARN MORE ABOUT FLOCKING
KIDS QUESTION: In the museum exhibit, we asked: Why do birds flock together?
The answer is: For safety from predators
Birds form flocks for a number of reasons. They are always on the lookout for predators (such as raptors or coyotes) and a predator is much more likely to be spotted by many birds than by a solitary bird. Flying in a flock can also confuse an airborne attacker. On the ground, birds flock together where there is a source of food and sometimes to keep each other warm.