The social suppression of caching in western scrub-jays (Aphelocoma californica)

This study focussed on the social suppression of caching in 3 groups of western scrub-jays (Aphelocoma californica). Each group (3 males and 4 females) were housed in a separate aviary. Only the dominant male and/or his partner cached in each aviary. When the alpha pair was removed from the aviary, however, caching by the beta pair increased significantly. As all subordinate birds cache when housed individually, cache cessation was attributed to social suppression. In each aviary, storers from both the alpha and beta pairs tolerated their partners recovering their caches, but treated all other birds aggressively if they approached a cache site. The storer and their partner tended to move one another's caches around multiple times, possibly making the final location of caches ambiguous. Importantly, caches were only moved around repeatedly on trials where multiple pilfering attempts were made. Western scrub-jays therefore appear to adjust their caching behaviour depending on the risk that observers pose to their caches.