However, when she and Dickinson focus on bird behaviors, they find that the cache-recovery pattern of scrub jays fulfills the what, where and when criteria for episodic recall. For instance, chickadees that tough out the winter in Siberia must find many of the half-million seeds they hide each year. In the worst of the season, the chickadees have only about 3 hours of daylight for foraging. Previous work has indicated that birds find their stashes not by smelling hidden food but by remembering the location. In laboratory tests, birds called Clark's nutcrackers have recalled where they buried something 9 months earlier.
Birds also remember what they've stored.
Blackcapped chickadees, for example, retrieve favorite foods first. To test for memories of specific events and their timing, Clayton and Dickinson let some scrub jays discover that waxmoth larvae, a favorite food, will rot after a few days. The researchers then gave the birds fresh larvae to bury in ice-cube trays full of sand. After five days, the jays cached peanuts. When these birds later had a chance to harvest their treats, they mostly probed for the peanuts and ignored the larvae locations.