Foraging and Flocking Strategies: Information in an Uncertain Environment

In this paper we have investigated the effects of uncertainty and information on the foraging strategies of animals. We first argue that group foraging, or flocking, can increase individual feeding rates as a result of the sharing of information among group members. Also, members of a foraging group may experience reduced variation in their feeding rates. Both of these advantages increase with the scarcity and patchiness of the food supply. On the other hand, our analysis also suggests that the informational advantages of flocking may tend to be dissipated by "overflocking," which is in fact an evolutionarily stable strategy. (Possible defense strategies against overflocking, such as territoriality or aggression, have not been considered here. We also discuss the strategy of individual foragers. We suggest that the traditional analysis in terms of marginal values, residence times, and giving-up times, may be misleading. It turns out to be important to "probe," especially in patches where food abundance is highly variable. The marginal value theorem fails completely to reflect this aspect of uncertainty and information.