Plasma metabolite concentrations of dunlins sampled at the Tagus estuary during spring (n = 62) and autumn (n = 53–55) migration.

Data (mean ± confidence intervals of the mean) are predictions from the selected model (see Table 2) where significant covariates were set with a constant mean value. For glycerol, predictions are presented for males and females separately, as sex was retained in the final model. Glycerol and uric acid concentrations were significantly higher and lower in spring than in autumn migrants, respectively (see Results).