Assessing the effects of repeated handling on the physiology and condition of semi‐precocial nestlings

Abstract

Repeated exposure to elevated levels of glucocorticoids during development can have long‐term detrimental effects on survival and fitness, potentially associated with increased telomere attrition. Nestling birds are regularly handled for ecological research, yet few authors have considered the potential for handling‐induced stress to influence hormonally mediated phenotypic development or bias interpretations of subsequent focal measurements. We experimentally manipulated the handling experience of the semi‐precocial nestlings of European Storm Petrel Hydrobates pelagicus to simulate handling in a typical field study and examined cumulative effects on physiology and condition in late postnatal development. Neither baseline corticosterone (the primary glucocorticoid in birds), telomere length nor body condition varied with the number of handling episodes. The absence of a response could be explained if Storm Petrels did not perceive handling to be stressful or if there is dissociation of the hypothalamic–pituitary–adrenal axis from stressful stimuli in early life. Eliciting a response to a stressor may be maladaptive for cavity‐dwelling young that are unable to escape or defend themselves. Furthermore, avoiding elevated overall glucocorticoid exposure may be particularly important in a long‐lived species, in which accelerated early‐life telomere erosion could impact negatively upon longevity. We propose that the level of colony‐wide disturbance induced by investigator handling of young could be important in underlining species‐specific responses. Storm Petrel nestlings appear unresponsive to investigator handling within the limits of handling in a typical field study and handling at this level should not bias physiological and morphological measurements.

Effect of GPS tagging on behaviour and marine distribution of breeding Arctic Terns Sterna paradisaea

“…It is possible that the reduced provisioning rates resulted principally from the disturbance associated with capture and handling rather than device attachment per se , although the similarity in provisioning rates of handled and unhandled birds in the 48 h immediately following capture suggests that the impacts of handling itself were minor. Although there are many studies of the effects of marks and device attachment on behaviour of birds (Calvo & Furness 1992, Bodey et al 2018) and many studies of the effect of handling on stress hormones (Watson et al 2010), we are unaware of any published studies of the effects of capture and handling on behaviour in wild birds, and this is an area which warrants further attention.…”

Short-term elevations in glucocorticoids do not alter telomere lengths: A systematic review and meta-analysis of non-primate vertebrate studies

“…Of the full-text articles, we removed 152 studies that did not fulfill our inclusion criteria. We statistically analyzed 15 of the remaining 31 studies, the ones that provided raw data for analysis [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. The other 16 studies appeared to fit criteria but did not provide raw data for analysis [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58].…”

Short-term elevations in glucocorticoids do not alter telomere lengths: A systematic review and meta-analysis of non-primate vertebrate studies

“…Of the 183 assessed full-text articles, we removed 152 studies that did not fulfill our inclusion criteria. We statistically analyzed 15 of the remaining 31 studies, the ones that provided raw data for analysis either within the manuscript or after contacting the corresponding author [16,22,[29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The other 16 studies appeared to fit criteria but did not provide raw data for analysis [26,30,[43][44][45][46][47][48][49][50][51][52][53][54][55].…”