2.3 Data analysis
We analyse the effect of sex, season and breeding regions on the monthly
home-range sizes, cumulative monthly distances travelled (normal error
distribution, identity link function), and percentage of monthly overlap
(beta error distribution, identity link function) using generalized
linear mixed models (GLMMs; glmmTMB package, Brooks et al., 2017). Sex,
season and breeding region were included as fixed factors, while
individual identity and year were included as random terms in the models
to avoid pseudoreplication.
Models were compared using the Akaike Information Criterion corrected
for small sample sizes (AICc; Burnham & Anderson, 2002). The best model
was the one with the lowest AICc value. All models with a difference of
ΔAICc < 2 were considered alternatives (Burnham & Anderson,
2002). For the best model, homogeneity of variance and normality of
residuals was inspected by using the “ggresid” package to check the
goodness-of-fit of our best models (Goode and Rey 2019). We estimated
the variance explained by the fixed and random factors by using the
“performance” package (Lüdecke et al., 2021), while differences
between their levels were assessed through Tukey posthoc tests using the
“emmeans” package (Lenth, 2022). All tests were two-tailed,
statistical significance was set at p < 0.05, and all results
were shown as mean ± standard deviation. Results of the Tukey post hoc
tests included the marginal means and its standard error. Spatial and
statistical analyses were done in R version 4.0.3 (R Core Team 2020).