Figure 4.

Predicted probability of tree selection by a nest‐site seeking bird, based on 176 paired use‐available‐data for diameter at breast height (DBH) measurements. Below 43 cm DBH trees are discriminated against, above that value they are selected for. Note that this does not describe the probability of a tree having a cavity, but of a bird selecting this tree diameter for nesting (Manly, McDonald, Thomas, McDonald, & Erickson, 2002, pp. 16). Individual studies may have contributed several nest‐tree DBH values for different bird species, forest types (e.g. logged vs. old‐growth) or trees (snags vs. live trees). The curve (solid line, dashed lines indicate 95% confidence intervals for fixed effects) was predicted from a generalized linear mixed model with two random effects for bird species and study