The strength of the avian stress response declines with age. A recently published study of European starlings (Sturnus vulgaris) found that a marker of biological age predicted the strength of the stress response even in individuals of the same chronological age. Specifically, birds that had experienced greater developmental telomere attrition (DTA) showed a lower peak corticosterone (CORT) response to an acute stressor, and more rapid recovery of CORT levels towards baseline. Here, we performed a follow-up study using the same capture-handling-restraint stressor in a separate cohort of starlings that had been subjected to a developmental manipulation of food availability and begging effort. We measured the CORT response at two different age points (4 and 18 months). Our data suggest a decline in the strength of the CORT response with chronological age: peak CORT was lower at the second age point, and there was relatively more reduction in CORT between 15 and 30 min. Individual consistency between the two age points was low, but there were modest familial effects on baseline and peak CORT. The manipulation of begging effort affected the stress response (specifically, the reduction in CORT between 15 and 30 min) in an age-dependent manner. However, we did not replicate the associations with DTA observed in the earlier study. We meta-analysed the data from the present and the earlier study combined, and found some support for the conclusions of the earlier paper.

The responsiveness of the avian stress system declines with age. A recently published study of European starlings (Sturnus vulgaris) found that a marker of biological age predicted stress responsiveness even in individuals of the same chronological age.Specifically, birds that had experienced greater developmental telomere attrition showed a lower peak corticosterone response to an acute stressor, and more rapid recovery of corticosterone levels towards baseline. Here, we performed a follow-up study using the same capture-restraint-handling stressor in a separate cohort of 27 starlings. Unlike the original study, we measured the response at two different age points (4 and 18 months).We did not replicate the associations with developmental telomere attrition observed in the previous study at either age point. However, a meta-analysis of the present results combined with those of the earlier study still lent some support to the conclusions of the earlier paper. Estimates of familial influence on stress responsiveness differed across the two age points. We found little evidence of individual consistency in stress responsiveness between 4 and 18 months. Peak corticosterone was significantly lower at the second age point than the first, though interpretation of this as age-related decline is problematic due to the samples having been analysed at different times. found that a marker of biological age predicted stress responsiveness even in 21 individuals of the same chronological age. Specifically, birds that had experienced greater developmental 22 telomere attrition showed a lower peak corticosterone response to an acute stressor, and more rapid 23 recovery of corticosterone levels towards baseline. Here, we performed a follow-up study using the same 24 capture-restraint-handling stressor in a separate cohort of 27 starlings. Unlike the original study, we 25 measured the response at two different age points (4 and 18 months). We did not replicate the associations 26 with developmental telomere attrition observed in the previous study at either age point. However, a 27 meta-analysis of the present results combined with those of the earlier study still lent some support to the 28 conclusions of the earlier paper. Estimates of familial influence on stress responsiveness differed across 29 the two age points. We found little evidence of individual consistency in stress responsiveness between 4 30 and 18 months. Peak corticosterone was significantly lower at the second age point than the first, though 31 interpretation of this as age-related decline is problematic due to the samples having been analysed at 32 different times. , 2015). Biological age is by definition a better predictor of future lifespan than 45 chronological age is. Hence, we should expect markers of individual biological age to explain variation in 46 stress responsiveness that cannot be explained by chronological age alone. A possible reason that early-47 life conditions have often been observed to influence the functioning of the adult stress respon...

The responsiveness of the avian stress system declines with age. A recently published study of European starlings (Sturnus vulgaris) found that a marker of biological age predicted stress responsiveness even in individuals of the same chronological age.Specifically, birds that had experienced greater developmental telomere attrition showed a lower peak corticosterone response to an acute stressor, and more rapid recovery of corticosterone levels towards baseline. Here, we performed a follow-up study using the same capture-restraint-handling stressor in a separate cohort of 27 starlings. Unlike the original study, we measured the response at two different age points (4 and 18 months).We did not replicate the associations with developmental telomere attrition observed in the previous study at either age point. However, a meta-analysis of the present results combined with those of the earlier study still lent some support to the conclusions of the earlier paper. Estimates of familial influence on stress responsiveness differed across the two age points. We found little evidence of individual consistency in stress responsiveness between 4 and 18 months. Peak corticosterone was significantly lower at the second age point than the first, though interpretation of this as age-related decline is problematic due to the samples having been analysed at different times. found that a marker of biological age predicted stress responsiveness even in 21 individuals of the same chronological age. Specifically, birds that had experienced greater developmental 22 telomere attrition showed a lower peak corticosterone response to an acute stressor, and more rapid 23 recovery of corticosterone levels towards baseline. Here, we performed a follow-up study using the same 24 capture-restraint-handling stressor in a separate cohort of 27 starlings. Unlike the original study, we 25 measured the response at two different age points (4 and 18 months). We did not replicate the associations 26 with developmental telomere attrition observed in the previous study at either age point. However, a 27 meta-analysis of the present results combined with those of the earlier study still lent some support to the 28 conclusions of the earlier paper. Estimates of familial influence on stress responsiveness differed across 29 the two age points. We found little evidence of individual consistency in stress responsiveness between 4 30 and 18 months. Peak corticosterone was significantly lower at the second age point than the first, though 31 interpretation of this as age-related decline is problematic due to the samples having been analysed at 32 different times. , 2015). Biological age is by definition a better predictor of future lifespan than 45 chronological age is. Hence, we should expect markers of individual biological age to explain variation in 46 stress responsiveness that cannot be explained by chronological age alone. A possible reason that early-47 life conditions have often been observed to influence the functioning of the adult stress respon...