Social and spatial drivers of the multitiered structure of zebra finch social networks

Social network structure plays a key role in shaping processes in animal populations. These networks often show distinct patterns in humans and other large mammals, with relationship strengths organized into different tiers. Here, we used continuous, fine-scale tracking of four large captive colonies of zebra finches (Taeniopygia guttata), revealing that zebra finches consistently have 1-2 closest contacts, 6-7 close contacts, and 22-24 strong contacts. The identities of these contacts remain stable across days, with strong contacts maintained by spatial affinity while closest and close contacts are maintained by social choice. These results suggest that zebra finches egocentric networks and social structure are made up of consistent, differentiated relationships forming a multitiered social structure. The similarities in patterns to other species suggest that fundamental principles, such as limitations in time and the ability to move through social space, could drive common structural properties in animal social networks.