Predicting Nest Success from Habitat Features in Aspen Forests of the Central Rocky Mountains

We collected nesting data on bird use of aspen stands in the Routt and Medicine Bow National Forests between 1987 and 1989. We found active nest sites of 28 species of small nongame birds on nine study plots in undisturbed aspen forests. We compared logistic regression models predicting nest success (at least one nestling) from nest-site or stand-level habitat predictors. Most common species used nest sites in aspen trees in forest interior locations (distance to edge \u3e100 m), with dense trees (opening \u3e100 m away) despite no apparent positive correlation with use of these habitat features and nest success rates. Further investigation may demonstrate that these forest interior sites do not experience lower predation and cowbird parasitism rates than nest sites near openings. We recommend adaptive management experimental treatments, including carefully planned cutting and controlled burns, that should benefit most birds in western aspen forests