Bell, K. E., & Baum, W. M. (2002).
Group foraging sensitivity to predictable and unpredictable changes in food distribution: Past experience or present circumstances?
Journal of the Experimental Analysis of Behavior,
78, 179-194.
The ideal free distribution theory (Fretwell & Lucas, 1970)
predicts that the ratio of foragers at two patches will equal the
ratio of food resources obtained at the two patches. The theory
assumes that foragers have "perfect knowledge" of patch
profitability and that patch choice maximizes fitness. How
foragers assess patch profitability has been debated extensively.
One assessment strategy may be the use of past experience with a
patch. Under stable environmental conditions, this strategy
enhances fitness. However, in a highly unpredictable environment,
past experience may provide inaccurate information about current
conditions. Thus, in a nonstable environment, a strategy that
allows rapid adjustment to present circumstances may be more
beneficial. Evidence for this type of strategy has been found in
individual choice. In the present experiments, a flock of pigeons
foraged at two patches for food items and demonstrated results
similar to those found in individual choice. Experiment 1
utilized predictable and unpredictable sequences of resource
ratios presented across days or within a single session. Current
foraging decisions depended on past experience, but that
dependence diminished when the current foraging environment
became more unpredictable. Experiment 2 repeated Experiment 1
with a different flock of pigeons under more controlled
circumstances in an indoor coop and produced similar results.
Key words: ideal free distribution, choice, foraging, group
foraging, matching law, undermatching, pigeons