Generalized linear mixed effects models testing a) bird abundance, b) evenness, c) species richness as a function of elevation (1000, 2000, 3000 m) and season (most humid and least humid), and d) species richness as a function of abundance, elevation and season.

Study plot nested in site and sampling months of each year were included as random effects in all models. All models assume a Poisson error distribution. Significant effects (p < 0.05) are printed in bold.