MANAGEMENT OF BALD EAGLE COMMUNAL ROOSTS IN FIRE-ADAPTED MIXED-CONIFER FORESTS

The Bear Valley National Wildlife Refuge in southern Oregon supports o ne of the largest concentrations (approx 300-400 individuals) of commu nally roosting bald eagles (Haliacetus leucocephalus) in the United St ates. Past selective logging and fire suppression in mixed-conifer for ests used by eagles at this roost have altered important roost charact eristics such that declines in roost suitability will continue without future management. Therefore, to evaluate long-term suitability of th e roost environment and to develop management prescriptions, we charac terized habitat features on 3 spatial scales: (1) attributes of trees used by eagles for roosting, (2) vegetation within 18 m of roost trees (i.e., roost sites), and (3) relative distribution of selected charac teristics within subroosts of the main roost. Roost trees had greater diameter at breast height (dbh), more open branching structures, and w ere taller than unused trees, Roost trees were primarily Douglas-fir ( Pseudotsuga menziesii) that were smaller in diameter and younger than other species of trees used for roosting; however, trees greater than or equal to 80 cm dbh were used by eagles. regardless of species. Roos t sites compared to unused sites had greater densities of tall (>30 m) trees of all species, greater densities of Douglas-fir that was 20-30 m tall, and a combination of greater densities of snags and Douglas-f ir that was 20-30 m tall. The subroost where a most site was located a lso may have affected the likelihood of a site being used by eagles du e to differences in densities of species of roost trees. Species compo sition and abundance of species of roost trees varied among subroosts due primarily to selective logging of Douglas-fir and ponderosa pine ( Pinus ponderosa), and to longterm fire suppression. We recommend limit ed thinning, prescribed fire, and seeding with species of roost trees to restore roost-tree composition and natural processes at this roost.