Burn severity and heterogeneity mediate avian response to wildfire in a hemiboreal forest

•Bird community patterns were best described by variations in burn severity.•High-severity burns had reduced abundance and richness of birds following fire.•Fire responses by most species were mediated by burn severity.•Burn heterogeneity and burn status were important for some species’ responses.•Results were similar when counts were either adjusted for detectability or not.