(ii) Factor analysis of behavioral traits
We applied factor analysis to reduce the number of behavioral traits
recorded and identify factors that may represent correlated behavioral
traits (Budaev 2010). We used principal axis factoring and a criterion
of minimum eigenvalue > 1 to extract the factors (Fabrigar
et al. 1999; Budaev 2010). Factor scores were based on correlations
after Varimax (= orthogonal) rotation of the factors. This method allows
extraction of orthogonal factors, and more stable and replicable results
in case of small sample size (Budaev 2010). Behavioral traits were
considered to contribute significantly to the factors when factor
loadings were > 0.80 (Table 2), which is above the
recommended threshold of 0.5 or 0.7 for behavioral analyses (Budaev et
al. 2010).