Selective adjustment of social associations and its influence on social networks in wild corvids

Abstract

The adjustment of social associations by individuals in response to changes in their social environment is a core principle of influential theories on the evolution of cognition1,2 and cooperation3,4. Selectively adjusting associations with others is thought to allow individuals to maximise short-term rewards from social interactions, thus re-shaping social networks to better favour connections between compatible group members5–8. Crucially, this has yet to be tested in natural populations, where the need to maintain long-term, fitness-enhancing relationships may limit social plasticity9,10. Using a novel social-network-manipulation experiment, we show that wild jackdaws (Corvus monedula) learned to favour social associations with compatible group members (individuals that provided greater returns from social foraging interactions). Consequently, the overall frequency of associations between compatible social partners increased as the experiment progressed. This resulted in clustering of compatible individuals within the social network, but the magnitude of this effect was small, likely due to the preservation of pre-existing long-term relationships. These results provide critical field evidence that learning to adjust social associations is beneficial whilst highlighting trade-offs with the need to maintain valuable long-term relationships. Our findings therefore provide important insights into the cognitive and behavioural basis of social network plasticity and the interplay between individual behaviour and social network structure in natural populations.