What defensive concept is provided by the pigeons' preference for feeding in flocks of up to 70 individuals?

Answer

Dilution effect

Feeding in flocks provides a dilution effect, which significantly reduces the mathematical probability that any single individual bird will become the target of a successful attack.

What defensive concept is provided by the pigeons' preference for feeding in flocks of up to 70 individuals?
birdPredatorfaunawildlifepigeon