USDA Forest Service

Pacific Northwest Research Station - Ecological Process & Function - Wildlife Ecology Team


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United States Department of Agriculture Forest Service.

Northern Spotted Owl (Strix occidentalis caurina) Research


Spotted owl with nestling



The primary objective of the demographic studies is to monitor population trends of spotted owls on federal lands. These studies are the primary method by which federal agencies determine how the population is performing in different regions and land management allocations. Data collected during these studies is also used by the US Fish and Wildlife Service (USF&WS) to evaluate progress towards recovery of the owl. In addition, biologists and managers from state and private organizations make extensive use of the site-specific data collected in the demographic studies to make management decisions and to consult with the USF&WS.

Demographic studies on federal lands consist of 8 long-term study areas including 2 in Washington (Olympic, Cle Elum), 1 in California (Willow Creek), and 5 in Oregon (Coast Range, Tyee, HJ Andrews, Klamath, Southern Cascades). Funding for these studies comes primarily from the Forest Service and Bureau of Land Management. Historically, Wildlife Ecology Team personnel have developed and supervised 4 of these studies (Tyee, Olympic, Cle Elum, Coast Range) and served as co-PI on another (HJ Andrews). The other 3 studies are conducted by the Oregon Cooperative Fish and Wildlife Research Unit (OCFWRU) at Oregon State University (South Cascades); The Colorado Cooperative Fish and Wildlife Research Unit, Colorado State University, (Willow Creek), and the Roseburg District, Bureau of Land Management (Klamath). All of these studies were initiated prior to the listing of the owl and the development of the Northwest Forest Plan.

Recent Annual Reports on Individual Studies



  • Habitat use and home range characteristics of spotted owls on the east slope of the Cascade Range, Washington

Recent Publications from our Spotted Owl Demograph Studies

  • Forsman, E. D., Anthony, R. G., Dugger, K. M., Glenn, E. M., Franklin, A. B., White, G. C., Schwarz, C.J., Burnham, K. P., Anderson, D. R., Nichols, J. D., Hines, J. E., Lint, J. B., Davis, R. J., Ackers, S. H., Andrews, L. S., Biswell, B. L., Carlson, P. C., Diller, L. V., Gremel, S. A., Herter, D. R., Higley, J. M., Horn, R. B., Reid, J. A., Rockweit, J., Schaberl, J., Snetsinger, T. J. and Sovern.S. G. 2011. Population demography of northern spotted owls: 1985–2008. Studies in Avian Biology.

  • Anthony, R.G., Forsman, E.D., Franklin, A.B., Anderson, D.R. , Burnham, K.P., White, G.C., Schwarz, C.J., Nichols, J.D. , Hines, J.E., Olson, G.S., Ackers, S.H., Andrews, L.S., Biswell, B.L., Carlson, P.C., Diller, L.V., Dugger, K.M., Fehring, K.E., Fleming, T.L., Gerhardt, R.P., Gremel, S.A., Gutie´rrez, R.J., Happe, P.J., Herter, D.R., Higley, J.M., Horn, R.B. , Irwin, L.L., Loschl, P.J., Reid, J.A., Sovern, S.G. 2006. Status and trends in demography of northern spotted owls, 1985-2003. Wildlife Monographs, 163. 1-48. (PDF, 1004 Kb)

  • Crozier, Michelle L., Mark E. Seamans, R.J. Gutierrez, Peter J. Loschl, Robert B. Horn, Stan G. Sovern, Eric D. Forsman. 2006.
    Does the presence of barred owls suppress the calling behavior of Spotted Owls? The Condor,108(4)pp760–769. *


[Photograph]: Spotted Owl with blue color band.

USDA Forest Service - Pacific Northwest Research Station - Olympia Forestry Sciences Laboratory
Last Modified: Monday, 16 December 2013 at 14:18:50 CST

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