Private and public information use strategies by foraging groups of wild Siberian jays

In variable environments variance-sensitive foraging should be replaced by more profitable sampling behaviour whenever the variation in foraging rewards becomes predictable enough to track. We tested this suggestion in groups of wild Siberian jays, Perisoreus infaustus, during prewinter food-hoarding visits to experimental feeders. As predicted, all groups of jays switched to sampling once food items were clumped into ‘patches’ to create reliable patch-based information concerning prey sizes. However, increases in individual foraging success above chance were not achieved according to a simple ‘win-stay lose-shift’ rule of thumb. Instead jays employed a win-and-return-later strategy, returning more often over the experimental session to privately sampled patches containing the four largest of five prey sizes. In contrast, public information that was gained by observing patch sampling by other group members involved a more gradual increase in the probability of patch use with the prey size involved. Use of public versus private information did not differ according to sex or social status. Even though the jays did not achieve the individually optimal strategy in this specific experimental set-up, their sampling behaviour using both public and private information are suggested to maximize both individual and group-wide foraging efficiencies when exploiting the ephemeral food sources typical of boreal taiga forests.

► We present an experiment on sampling by groups of wild Siberian jays.
► Foraging performance was improved by use of both private and public information.
► The jays did not use a simple win-stay lose-shift strategy.
► Performance was improved by a longer term learning rule.
► Variance-sensitivity was abandoned for sampling when information was available.