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
The haematocrit rate of the blood shows the individual physiological state. As the haematocrit grows, the higher erythrocyte number results in more efficient oxygen uptake capacity which can lead to better performance and probably a better survival rate of an individual. Hence we assume that the high value of haematocrit reflects good health state. Altogether 308 blood samples were collected from a wild population of Collared Flycatchers (Ficedula albicollis) in two breeding stages during a period of 2008-2010. We tried to elucidate the relationship between condition and haematocrit level of an individual and studied the haematocrit changes of an individual between years. The haematocrit values differed between years. Females had higher haematocrit values than males in 2010 but not in 2009. At courtship the haematocrit level of males was higher, than during nestling care. The different environmental effects and energy demands of the individuals may be the driving force behind the observed changes in haematocrit level. Analysing the changes between two years, there was a positive correlation between changes in condition index and haematocrit of individuals. The haematocrit values of an individual were repeatable between years. This finding suggests that haematocrit can be informative about the individual’s general health state.