A study of optimal foraging in the eastern chipmunk (Tamias striatus)

The foraging of five, wild, free-roaming eastern chipmunks (Tamias striatus) was studied at artificial feeding stations to test several models of optimal foraging. Artificial feeding stations were eight boards (15 cm x 30 cm) with 24 holes in each. Sunflower seeds were placed in the holes and covered with sand. It was quite clear that the chipmunks did not decide to abandon a board according to the predictions of the marginal value theorem. Similarly, stochastic models (e.g. Green, 1980; Oaten, 1977) did not predict foraging behavior. Rather, the chipmunks formed a time-expectation which allowed them to forage efficiently, but not optimally. The cost of not foraging optimally may be smaller than expected since many departures from boards were based on considerations other than foraging. Chipmunk foraging behavior was highly variable within and between individuals.