Boxplots (description see Fig 1) of concentrations of glucocorticoid metabolites (GCM; ng/g droppings) of female Blue-fronted parrots (Amazona aestiva), kept under natural light variation (sunrise: 06:02 ± 0:11 a.m.—sunset: 06:09 ± 0:03 p.m.–mean ± standard deviation), after an injection of saline solution (0.9% NaCl; white boxes), dexamethasone (1 mg/Kg; white striped boxes) and adrenocorticotropic hormone (25 IU of ACTH; gray striped boxes).

The control group was kept in the same room but remained undisturbed (gray boxes). Please note the different y-axis scale in the upper (Dexamethasone; ACTH) and lower (Saline; Control) panels. Asterisks beside the gray striped boxes indicate significant differences compared with the same interval of the control group (P < 0.01). The P values of time (T), treatments (Treat) and the interaction time*treatments (T*Treat) are shown.