3.1. Relationship between behavioral variables and hormone levels
The PCA generated three components with eigenvalues greater than 1 and accounted for 76.69% of the total variation (Table 1). The first component (PC1) encompassed the major source of variation (45.85%) and showed positive association with temperature and the main temporal parameters of calling activity (mean calling rate, maximum calling rate, minimum calling rate, minutes with vocal activity, and vocal behavior category). PC2 accounted for 17.89% of the variance and displayed positive association with the call rate range, locomotion and adjustments of position. Thus, variation in PC2 was primarily associated with an individual's tendency to move, to adjust position and calling behavior. The third component (PC3) explained 12.95% of variance, and encompassed mainly date and time. CORT and T were positively associated across the breeding season (Table 2, Fig. 2a). CORT correlated positively with PC1 and both CORT and T correlated positively with PC2 (Table 2, Fig. 2).