Raven

Ravens cache food and adjust their caching and re-caching behaviour according to whether a competitor observed them, protecting caches more when they had been watched.

Ravens guarded caches more intensively when they could hear a competitor through a peephole, indicating they generalise about being seen rather than merely responding to a visible bird.

Ravens solve multi-step problems including string-pulling and delayed exchange, and in captivity plan for future tool use and barter — performance comparable to great apes on the same tasks.

Ravens associate with wolf packs at kills, following hunting wolves and feeding at carcasses they cannot open themselves; the relationship is well enough documented that ravens are called 'wolf-birds'.

Ravens engage in apparently non-functional play including aerial tumbling, sliding down snowbanks and object play, behaviour unusual outside mammals and a small number of bird families.

Ravens reciprocate agonistic support over long intervals, remembering who backed them in a conflict and returning it later — support given correlates with support received across months.

Ravens remember whether an individual traded fairly or cheated them, and preferentially avoid the unfair partner in later exchanges — a memory demonstrated at least a month later.

Ravens track dominance relationships among other ravens, including birds outside their own group, and react with surprise to playback implying a reversal of a known hierarchy.

Bystander ravens direct affiliative behaviour toward victims of aggression with whom they share a valuable relationship, a pattern described as consolation.

Ravens form long-term pair bonds and defend a shared territory for years; the pre-pair phase is spent in loose non-breeding flocks where most of the social learning happens.