"In Antarctica, climate change has negative impacts on seabird populations. However, this change is likely to differentially affect birds depending on their age, experience and quality. This heterogeneous response to climate change deserves attention because it will affect the structure of populations and thus, their health status. This project aims to examine how age, experience and quality can functionally affect the way Antarctic seabirds respond to environmental perturbations. Moreover, we will focus on physiological age because it is more likely to determine bird’s response to perturbations than chronological age. To sum up, we aim to examine how age, experience and quality determine to what extent parents (1) are energetically constrained; (2) regulate their parental investment when facing perturbations. We will use (a) stress physiology (corticosterone, COR) to test our hypotheses; (b) telomere dynamic to measure physiological age. In the context of global change, COR physiology is promising because it mediates the response of an organism to environmental stressors: COR physiology is a system with 2 functional levels (baseline and stress-related COR levels), which have been suggested as indicators of energetic constraints and parental investment. However, data are lacking to confirm this interpretation. We will link the knowledge in stress and aging physiology of Wingfield with the long-term ecological data set of the CEBC-CNRS and we will use innovative techniques to address three questions: (1) Is telomere length a reliable measure of physiological age? (2) Can baseline COR level and COR stress response mirror energetic constraints and parental investment? (3) Do age (chronological, physiological), experience and quality interact with environmental conditions to affect COR levels? Thus, we will better understand how Antarctic birds react to climate change in term of energetic constraints and parental investment depending on their age, experience or quality"