The association between corticosterone metabolite concentrations (ng/g) and sampling year in relation to the phase of reproduction, i.e., females during incubation and males and females during nestling feeding.

Points denote the means and bars (SE±). We tested the effect of year on corticosterone metabolites using a multiple regression analysis (See supporting information table D for model details). The significance between years is depicted as not significant (ns), and <0.01 (**). Samples with missing values were removed from the analysis.