Bald Eagle Winter Habitat on Southwestern National Forests

100 bald eagles aerial surveys American coot area of aspen area of Engelmann area per tree behavior canopy central Rocky Mountains Colo Colorado State University conifers Department of Game determinations for subalpine Douglas-fir eagle winter habitat eagles in Arizona Edminster Effective projected leaf Engelmann spruce estimating leaf area foraging areas Forest and Range Forest Service Research Fort Collins Grubb habitat managers habitat study insights for habitat Keywords lakes Leaf area determinations leaf area index leaf area m² Limited in number lodgepole pine Mexico Needle area opportunistic eagle perch trees Perching habits varied pine and leaf Pinyon pine Ponderosa pine projected leaf area Range Experiment Station River Rocky Mountain Forest roosts appear sapwood Service Research Paper Skagit River southwestern National Forests stand basal area subalpine fir subalpine tree species survey and habitat Teryl G total leaf area tree basal area tree height USDA Forest Service waterfowl wintering bald eagles wintering eagles