Conservation Implications of a Multi-scale Study of Flammulated Owl (Otus flammeolus) Habitat Use in the Northern Rocky Mountains, USA

—Our multi-scale analysis of Flammulated Owl ( Otus flammeolus) habitat use in the norther n Rocky Mountains indicates some landscapes may be unsuitable for this species. As a r esult, there may be less habitat available for Flammulated Owls than thought based on the r esults of micr ohabitat studies. Thus, we suggest Flammulated Owl habitat conservation measur es be based on the r esults of landscape-level, as well as micr ohabitat studies. Habitat conservation and r estoration ef forts in the ponder osa pine ecosystem should r etain large trees, large snags, understory tr ee thickets, and grassland openings within landscapes that contain an abundance of suitable for est types. Effective conservation strategies cannot be designed without understanding the distributions of rar e species. Bird distributions ar e heavily dependent on habitat distribution (reviews in Cody 1985), partly because populations are limited by the availability of suitable habitat. Thus, identifying and maintaining adequate amounts of suitable habitat ar e critical to supporting population sizes and structur es necessary for long-ter m species viability. Flammulated Owls ( Otus flammeolus) in the central Rocky Mountains (Haywar d 1986, Reynolds and Linkhart 1992) and Blue Mountains (Bull et al. 1990) predominantly nest and forage in old-gr owth ponderosa pine (Pinus ponderosa) forests, suggesting the species depends on the ponder osa pine ecosystem for population viability in some geographic ar eas. This ecosystem has been heavily alter ed by past forest management in the norther n Rocky Mountains. Specifically, the r emoval of over story ponderosa pine since the early 1900’s and nearly a century of fir e suppression have led to the r eplacement of most old-gr owth ponderosa pine forests by younger forests with a greater proportion of Douglas-fir (Pseudotsuga menziesii var. glauca) than ponderosa pine (Habeck 1990). Clear cut logging and subsequent r eforestation have converted many older stands of ponder osa pine/Douglasfir forest to young structurally-simple ponderosa pine stands (Wright and Bailey 1982). Fire scar evidence in the norther n Rocky Mountains indicates that ponder osa pine forests bur ned approximately every 1-30 years prior to fir e suppression, preventing contiguous understory development and, thus, maintaining relatively open ponderosa pine stands (Arno 1988, Habeck 1990). In old for ests that r etain a ponderosa pine overstory, a century of fir e exclusion has per mitted development of a mor e contiguous dense Douglas-fir understory (Mutch et al. 1993). USDA For est Service personnel entrusted with the management of national for ests in the norther n Rocky Mountains are curr ently investigating techniques to remove understory Douglas-fir and r etur n preEuropean-settlement fir e regimes to ponder osa pine ecosystems (Mutch et al. 1993). National Forests such as the Bitterr oot and Lolo National For ests in west-central Montana ar e proposing to r estore old-growth ponderosa pine forests by removing Douglas-fir fr om mixed ponderosa pine/Douglas-fir stands to incr ease the pr oportion of ponder osa pine tr ees relative to Douglas-fir , and to thin the Douglas-fir understory. Alteration of for est conditions 1 Wildlife Biologist, USGS, Biological Resour ces Division, Science Center , Glacier National Park, West Glacier, MT 59936; Resear ch Wildlife Biologist, USDA For est Service, Inter mountain Research Station, P .O. Box 8089, Missoula, MT 59807; Professor, Division of Biological Sciences, University of Montana, Missoula, MT 59812, respectively.