Memory for the content of caches by scrub jays (Aphelocoma coerulescens)

To test whether scrub jays (Aphelocoma coerulescens) remember the contents of food caches, in Experiment 1 birds cached peanuts and kibbles in two distinct caching trays and recovered them 4 or 172 hr later. The relative incentive value of the foods was manipulated by prefeeding one of the foods immediately before cache recovery. Birds preferentially searched for non-prefed food caches even when the caches had been pilfered prior to the recovery test. In Experiment 2, birds cached both foods in different sites within each tray, recovering peanuts from one tray and kibbles from the other tray 3 hr later. After prefeeding with one food, birds preferentially searched tray sites in which they had cached but not retrieved the non-prefed food. Thus jays remember the specific foods they cache and recover by a mnemonic process that cannot be explained in terms of simple associations between the foods and their cache locations.