Behavioural responses to handling stress in the Great Tit: within-individual consistency and the effect of age, sex and body condition

Abstract In birds, individuals may show different behavioural and physiological responses when handling, and such variation may be related to individual differences in antipredator strategies. We performed a pilot study in both breeding and wintering populations of the Great Tit (Parus major), and we characterised three typical behavioural traits during a standard ringing procedure in captured birds. We assessed between- individual variations in breath rate, pecking rate and the number of distress calls displayed in response to handling, and also calculated the within-individual variation of these traits by repeated behavioural measurements. We found that these behaviours were consistently displayed within individuals (with repeatability varying between 0.44 and 0.82), and there was also some modest correlation between them (e.g. breath rate covaried with the number of distress calls). Furthermore, using multivariate linear models assessing a role of some potential predictors we found that a considerable amount of between-individual variation can be explained by sex and age differences and also by variation in body condition. However, the magnitude and direction of these relationships was inconsistent across seasons. Our results are in line with previous findings that several consistent behavioural traits measured during human handling could reflect individual specific antipredator strategy, but some confounding effects cannot be ruled out. Hence, our preliminary results require careful interpretation, and further studies are needed to assess the exact magnitude by which different behavioural traits are inter-related