Perturbations highlight importance of social history in parakeet rank dynamics

Dominance hierarchies can provide many benefits to individuals, such as access to resources or mates, depending on their ranks. In some species, rank can emerge as a product of a group's history of social interactions. However, it can be difficult to determine whether social history is critical to rank in observation-based studies. Here, we investigated rank dynamics in three captive groups of monk parakeets (Myiopsitta monachus). We used experimental social perturbations to test whether social history shapes rank emergence in these groups. Using targeted removals and reintroductions, we tested whether differently ranked individuals could re-take their ranks in hierarchies after reintroduction following their removal period from the group. We performed perturbations that consisted of an 8-day removal and an 8-day reintroduction period of 15 differently ranked focal birds. We found that no focal birds could regain their previous rank immediately following reintroduction and that the top-ranked birds showed greater relative rank loss than middle/low-ranked birds. We also found that morphology, specifically bodyweight, was unassociated with rank. Combined with previous results, this experiment supports the hypothesis that rank in monk parakeet dominance hierarchies is more likely to be an emergent outcome of past interactions and memory rather than based on individual characteristics. Gaining a better understanding of how individuals achieve and maintain rank can give insight into the role of cognition on rank acquisition, as rank position can have significant biological effects on individuals in hierarchically structured groups. Dominance rank can influence many aspects of an individual's biology, but the factors that determine rank can vary widely across species. We manipulated group membership to determine whether rank is the product of a group's social history (memory of past interactions) in captive monk parakeets. After reintroducing removed individuals, no removed bird could immediately re-take their rank, and bodyweight did not correlate with rank. Our results provide support that social history shapes rank in monk parakeets.

Automated summary

Dominance hierarchies can provide benefits depending on ranks, and rank can emerge from a group's social history. In this study, we investigated rank dynamics in captive monk parakeets and found that social history shapes rank emergence. After reintroduction, no individuals could immediately regain their previous rank, and top-ranked birds showed greater rank loss. Bodyweight was also found to be unassociated with rank.