Explanatory variables used to model AIV prevalence in Spanish wetlands.

Variables marked with * were excluded as highly correlated (Spearman's coefficient ≥ |0.6|) with other variables within their factor.
1Flamingos and White storks were considered separately due to previous epidemiological data obtained in the area that identified these species as important AIV carriers [17], [18].
2In this index we grouped dabbling ducks and flamingos due to similar feeding habits, as both avian groups feed on surface water, which has been identified as a risk factor in AIV epidemiology [24].