Stress responses to repeated captures in a wild ungulate

While capture-mark-recapture studies provide essential individual-level data in ecology, repeated captures and handling may impact animal welfare and cause scientific bias. Evaluating the consequences of invasive methodologies should be an integral part of any study involving capture of live animals. We investigated short- and long-term stress responses to repeated captures within a winter on the physiology, behaviour, and reproductive success of female Svalbard reindeer (Rangifer tarandus platyrhynchus). Short-term responses were evaluated using serum concentrations of glucocorticoids and catecholamines during handling, and post-release recovery times in heart rate and activity levels. Repeated captures were associated with an increase in measured catecholamines and glucocorticoids, except cortisone, and delayed recovery in heart rate but not activity. Four months later, in summer, individuals captured repeatedly in winter exhibited a small increase in behavioural response to human disturbance and had a lower probability of being observed with a calf, compared to animals not captured, or captured only once. Our findings imply that single annual capture events have no significant negative consequences for Svalbard reindeer, but repeated captures within a season may impact offspring survival in the same year. Such unanticipated side effects highlight the importance of addressing multiple indicators of animal responses to repeated captures

Early-life variation in migration is subject to strong fluctuating survival selection in a partially migratory bird

We thank everyone who contributed to long-term field data collection, particularly Raymond Duncan, Sarah Fenn, Hannah Grist, Carl Mitchell, Calum Scott, Jenny Sturgeon, Moray Souter, John Anderson, and Harry Bell; NatureScot for allowing work on the Isle of May National Nature Reserve, and Isle of May Bird Observatory Trust for supporting the long-term ringing; and Suzanne Bonamour and Kenneth Aase for helpful discussionsPeer reviewe

Season-specific genetic variation underlies early-life migration in a partially migratory bird

Open Access via the Royal Society Agreement Acknowledgments We thank everyone who contributed to long-term field data collection, particularly Raymond Duncan, Sarah Fenn, Hannah Grist, Carl Mitchell, Calum Scott, Jenny Sturgeon, Moray Souter, John Anderson, and Harry Bell; NatureScot for allowing work on the Isle of May National Nature Reserve, and Isle of May Bird Observatory Trust for supporting the long-term ringing. We thank Suzanne Bonamour, Craig Walling and two anonymous reviewers for helpful feedback.Peer reviewe

Early‐life variation in migration is subject to strong fluctuating survival selection in a partially migratory bird

1. Population dynamic and eco-evolutionary responses to environmental variation and change fundamentally depend on combinations of within- and among-cohort variation in the phenotypic expression of key life-history traits, and on corresponding variation in selection on those traits. Specifically, in partially migratory populations, spatio-seasonal dynamics depend on the degree of adaptive phenotypic expression of seasonal migration versus residence, where more individuals migrate when selection favours migration. 2. Opportunity for adaptive (or, conversely, maladaptive) expression could be particularly substantial in early life, through the initial development of migration versus residence. However, within- and among-cohort dynamics of early-life migration, and of associated survival selection, have not been quantified in any system, preventing any inference on adaptive early-life expression. Such analyses have been precluded because data on seasonal movements and survival of sufficient young individuals, across multiple cohorts, have not been collected. 3. We undertook extensive year-round field resightings of 9359 colour-ringed juvenile European shags Gulosus aristotelis from 11 successive cohorts in a partially migratory population. We fitted Bayesian multi-state capture-mark-recapture models to quantify early-life variation in migration versus residence and associated survival across short temporal occasions through each cohort's first year from fledging, thereby quantifying the degree of adaptive phenotypic expression of migration within and across years. 4. All cohorts were substantially partially migratory, but the degree and timing of migration varied considerably within and among cohorts. Episodes of strong survival selection on migration versus residence occurred both on short timeframes within years, and cumulatively across entire first years, generating instances of instantaneous and cumulative net selection that would be obscured at coarser temporal resolutions. Further, the magnitude and direction of selection varied among years, generating strong fluctuating survival selection on early-life migration across cohorts, as rarely evidenced in nature. Yet, the degree of migration did not strongly covary with the direction of selection, indicating limited early-life adaptive phenotypic expression. 5. These results reveal how dynamic early-life expression of and selection on a key life-history trait, seasonal migration, can emerge across seasonal, annual, and multi-year timeframes, yet be substantially decoupled. This restricts the potential for adaptive phenotypic, microevolutionary, and population dynamic responses to changing seasonal environments

Data used in "Stress responses to repeated captures a wild ungulate"

Methods are described in detail in "Evaluating animal stress responses to repeated captures: an integrated approach" (published in Scientific Reports): 10.1038/s41598-022-20270-z See readme.txt for details regarding each data set.  </p