From PhysOrg:
New research published today, Wednesday 15 September, in New Journal of Physics, uses a particle model to explain the collective decision making process of flocks of birds landing on foraging flights. Using a simple self-propelled particle (SPP) system, which sees the birds represented by particles with such parameters as position and velocity, the researchers from Budapest, Hungary, find that the collective switching from the flying to the landing state overrides the individual landing intentions of each bird.
In the absence of a decision making leader, the collective shift to land is heavily influenced by perturbations the individual birds are subject to, such as the birds' flying position within the flock. This can be compared to an avalanche of piled up sand, which would occur even for perfectly symmetric and cautiously placed grains, but in reality happens much sooner because of increasing, non-linear fluctuations.
More here.
