Model selection of analyses that examined the presence of bluebird or swallow nests in aspen groves and continuous forest sites.

N = 39 and 276 site-years in aspen groves and continuous forests, respectively. The presence of nests was related to the density of cavities (logarithmic-transformed) supplied by the ecosystem engineers: northern flickers, red-naped sapsuckers, hairy woodpeckers and rot-fungi insects. Site size was fitted as a fixed term in all models to control for its potential effect on nest detection. LogLik: log-likelihood, AICc: AIC corrected for small sample size, ΔAICc: difference in AICc to the best model. Models of each model set for each bird species and habitat type are ranked according to their Akaike weight (Weight).