“…The ontogeny of stress is still poorly understood but it is known that it may, for instance, shape pre‐migratory movements (Pakkala et al ., 2016) and to a further extent adult physiology, behaviour and fitness (Schoech, Rensel & Heiss, 2011; Crespi et al ., 2013). Additionally, CORT level differences between sexes in nestlings are rarely integrated into analyses (Tilgar, Saag & Moks, 2009; Wada et al ., 2009; Rensel, Wilcoxen & Schoech, 2010; Tilgar et al ., 2010; Kidawa et al ., 2014; Pakkala et al ., 2016; Newman et al ., 2017; Injaian, Taff & Patricelli, 2018; Injaian et al ., 2019; Bebus, Jones & Anderson, 2020; Expósito‐Granados et al ., 2020), or evidenced either no difference (Sockman & Schwabl, 2001; Beaugeard et al ., 2019; Grunst et al ., 2020) or low sex effects (Rensel, Wilcoxen & Schoech, 2011). This slight decrease in stress‐induced response in males may arise from habituation (i.e.…”