**3. Results**

#### *3.1. Physiological Stress Reactions*

Concentrations of plasma and hair cortisol and its metabolites in feces were not correlated (Table 1). There was only a weak, but not significant correlation of cortisol in hair with fecal cortisol metabolites (FCMs).

Concentrations of plasma cortisol did not show differences between sex (F(1,43) = 0.361; *p* = 0.551) or age classes (F(2,43) = 0.074; *p* = 0.929). Comparison of plasma cortisol concentrations between months showed marginally significant differences (F(3,43) = 2.809; *p* = 0.051) between the first and last months of the hunting season (Figure 1a). These results were not affected by BMF levels (F(1,42) = 0.029; *p* = 0.866). However, the percentage of lymphocytes was associated with the concentration of plasma cortisol (F(1,42) = 5.947; *p* = 0.019; β = 2.553). Once we controlled for the percentage of lymphocytes, the differences between months became more pronounced (F(3,42) = 4.356; *p* = 0.009). FCM levels did not differ significantly in terms of sex (F(1,67) = 0.769; *p* = 0.384), age class (F(2,67) = 1.589; *p* = 0.212) or month (F(3,67) = 0.367; *p* = 0.777; Figure 1b). Moreover, FCM levels were neither significantly influenced by the BMF levels (F(1,65) = 3.206; *p* = 0.078) nor by the percentage of lymphocytes (F(1,44) = 1.151; *p* = 0.289). Additionally, FCM values from hunted animals were higher (99.72 ± 11.33 ng/g) than those found in wild animals at control areas (51.17 ± 6.89 ng/g), for the same month (i.e., November). Regarding hair samples, levels of cortisol did not differ between sex (F(1,69) = 2.959; *p* = 0.090) and age classes (F(2,69) = 1.570; *p* = 0.215). Cortisol levels in hair differed between months (F(3,69) = 3.805; *p* = 0.014), with the highest values recorded in February and the lowest in October (Figure 1c). Cortisol levels in hair were neither influenced by BMF (F(1,68) = 1.659; *p* = 0.202) nor the percentage of lymphocytes (F(1,46) = 2.371; *p* = 0.130), and the differences and patterns between months remained the same even after controlling for BMF levels and the percentage of lymphocytes.


**Table 1.** Pearson correlations between the concentrations of cortisol (metabolites) in plasma, feces and hair.

**Figure 1.** Patterns of cortisol (metabolite) levels in (**a**) plasma (**b**) feces and (**c**) hair during the hunting season (October to February). The values represent the estimated means from the general linear models and the bars represent the 95% confidence intervals.

#### *3.2. Physical and Immunological Conditions*

In terms of physical condition, measured by the BMF index, we found significant differences between the sexes (F(1,72) = 43.370; *p* < 0.001), age classes (F(2,72) = 6.842; *p* = 0.002) and months (F(3.72) = 3.288; *p* = 0.025). Females had higher BMF values than males in all months (Figure 2). The differences obtained between age classes were mainly due to the poorer physical condition of calves (79.6; 95% CI [68.2, 87.6]) when compared with sub-adults (92.9; 95% CI [90.0, 94.9]) and adults (92.8; 95% CI [90.0, 94.8]). Regarding months, the animals had higher values of BMF in January (93.4; 95% CI [89.9, 95.8]) than in November (85.5; 95% CI [79.6, 90.0]). Lastly, white blood cells did not differ between sexes, age classes or across months (*p* > 0.05 for all models).

**Figure 2.** Patterns of bone marrow fat (BMF) levels for red deer females (black circles) and males (white squares) during the different months of the hunting season. The values represent the estimated means from the general linear models and the bars represent the 95% confidence intervals.
