Boxplots of diurnal variation of concentrations of glucocorticoid metabolites (GCM; ng/g droppings) of Blue-fronted parrots (Amazona aestiva), kept under natural light variation (sunrise: 06:23 a.m.—sunset: 06:03 p.m).
Respective median values are showed as a line in the boxes. Lower and upper boundaries of the boxes indicate the 25th and 75th percentiles, respectively. Whiskers above and below the box indicate the 90th and 10th percentiles. Outliers are show as points. Asterisks beside the box indicate significant differences compared with the 5 to 8 p.m. interval (P ≤ 0.005).