Best-supported logistic regression model fitted to explain variation in AIV infection probability in Blue-winged Teal in Canada and the US, 2007–2010 (n = 13,574).

Abbreviations: β = coefficient estimate, SE = standard error, CI (95% confidence interval), ref = reference, HY = hatch year, AHY = after hatch year. Latitude is standardized to have a mean of 0 and standard deviation of 1. The quadratic term is the standardized latitude squared. Age*Season is the interaction term. Best-supported logistic regression model fitted to explain variation in AIV infection probability in Blue-winged Teal in Canada and the US, 2007–2010 (n = 13,574).