Northern Spotted Owl (Strix occidentalis caurina) Research
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
COMPANION NORTHERN SPOTTED OWL DEMOGRAPHIC
Conducted by Dr. Katie Dugger (Principal Investigator),
Oregon Cooperative Fish and Wildlife Research Unit (OCFWRU), Department
of Fisheries and Wildlife, Oregon State University, Corvallis,
Demography of Northern Spotted Owls (Strix occidentalis caurina)
on the Willamette National Forest, Oregon.(PDF 152KB)
Characteristics of Spotted Owls (Strix occidentalis caurina)
in the Southern Oregon Cascades, 2012. (PDF 108 MB)
Conducted byCooperative Fish & Wildlife Research Unit, Colorado
State University,Fort Collins, CO 80523 & Dr. R. J. Gutiérrez,
University of Minnesota, Department of Fisheries, Wildlife, and
Conservation Biology, St. Paul, MN 55108.
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.
the presence of barred owls suppress the calling behavior of Spotted
Owls? The Condor,108(4)pp760769. *