Many animals are at risk of being eaten by other animals. Such an animal must balance food intake with predation risk. These models simulate Pulliam's (1973) vigilance model, which suggests that feeding in flocks is advantageous.

Collective - Foraging juncos can be attacked by a Cooper's Hawk. Foraging rate and duration can be adjusted.

Individual - Individual parameters can be adjusted. This model introduces game theory and illustrates that the best strategy for a group is prone to “cheating” individuals.