Personality and fecal glucocorticoid metabolite concentrations are associated with post-release fitness in translocated swift foxes (Vulpes velox)

Conservation translocations can promote species recovery but are prone to failure due to low post-release survival. Mounting evidence suggests that intrinsic attributes like personality and stress physiology can impact how individuals cope with translocation and acclimatize to the release site. Here, we investigated relationships among personality, biomarkers of stress, post-release movement, and survival using a recent swift fox ( Vulpes velox ) reintroduction program as a case study. We scored pre-release behavioral responses to handling and collected fecal samples ( n = 329) from 76 foxes translocated from three wild populations across Colorado and Wyoming to the Fort Belknap Reservation, Montana, in 2021-2022. Our behavioral assessments measured the degree to which foxes were proactive (i.e., active, risk-taking, less docile) or reactive (i.e., inactive, risk-averse, more docile). We quantified fecal glucocorticoid metabolite (fGM) concentrations for the first time in swift foxes and monitored foxes’ post-release movements and survival using GPS data. Generalized linear models indicated that foxes with the lowest and highest fGM concentrations were more reactive during handling. Further, foxes with higher fGM concentrations around the time of capture traveled greater cumulative distances post-release. Personality had a non-linear effect on survival such that foxes with the most proactive and reactive behaviors during handling were more likely to survive in the first 60 days post-release. Ultimately, release cohorts comprising an array of individual temperaments may best cope with the novelty of the release site through behaviorally mediated resource partitioning and risk avoidance.