Eurasian jays, Garrulus glandarius, flexibly switch caching and pilfering tactics in response to social context

Corvids such as jays and ravens cache food for future consumption and can remember the location of caches that they have seen others make. Given the risk of caches being pilfered by observers, corvids limit opportunities for conspecifics to witness caching events. Faced with cache protection tactics, pilferers should also utilize tactics to maximize their success. Cacher–pilferer interactions and their underlying cognition have largely been investigated in semisocial ravens, Corvus corax, and western scrub-jays, Aphelocoma californica. However to understand the factors influencing the development of these abilities, data are required from species that differ in their socioecology from ravens and western scrub-jays. In the current study, we tested the caching and pilfering behaviour of territorial Eurasian jays in two social contexts. In one context, subjects competed with a dominant conspecific, while in the other the same individuals interacted with a subordinate competitor. When subordinate, birds initially suppressed caching, before caching more in less exposed locations. In contrast, when socially dominant, birds cached more and moved items multiple times. As subordinate pilferers, birds took longer to approach cache sites and approached when the cacher was at a distance, while when dominant, birds rapidly approached the conspecifics’ cache sites, frequently when the cacher was still in the process of caching. Individual jays therefore flexibly switched caching and pilfering tactics in response to the relative dominance of their competitor. We discuss the implications of our results for competing theories on the origin of behavioural flexibility and its underlying complex cognition in the corvid lineage.