Observational study reveals personality-dependent flock sorting before migration in wild chestnut thrushes, suggesting individual movement drives collective group personality.
Key Points
To determine whether seasonal flock personality composition is linked to the exploratory behavior of individual members before winter migration in wild chestnut thrushes.
Assessed exploratory behavior across 208 wild chestnut thrushes (Turdus rubricanus) across breeding and non-breeding seasons in 2019 and the 2020 breeding season.
Tracked 40 individuals categorized into seven distinct flocks prior to the 2019 winter migration.
Calculated flock exploratory scores using linear mixed models and evaluated score repeatability across flock membership changes.
Flock size was negatively associated with Julian date, decreasing as migration approached, but showed no relationship with flock exploratory scores.
Exploratory behavior scores differed significantly among flocks regardless of changes in individual flock membership.
Flock exploratory scores were repeatable only after three individuals switched flocks, indicating that membership changes drove stable group personality profiles.