Oregon Project
Barred owls in the Pacific Northwest: using an experimental removal project to understand predator-prey interactions of a non-native raptor.
September 2016 - March 2023
Personnel
Participating Agencies
- USGS - FRESC
The barred owl (Strix varia) is a medium-sized forest owl native to eastern North America (Mazur and James 2000). Starting in the late 1800’s, the barred owl began expanding its geographic range north and west, and their newly expanded range now completely overlaps that of the federally threatened northern spotted owl. Strong evidence indicates that competition with invading barred owls is causing rapid declines in populations of spotted owls, and that in some portions of the Pacific Northwest, barred owls now occur at much greater densities relative to spotted owls. However, little research exists on the overall impacts of this newly established apex predator on other forest species (besides spotted owls) and food-web dynamics. In collaboration with USGS-FRESC and USFWS, this project will take advantage of the experimental design associated with an on-going barred owl removal experiment to evaluate the impact this novel avian predator is having on the food web in the PNW. Understanding the impact of barred owls on the food web is critical for spotted owls and other native species, particularly as barred owl densities reach carrying capacity in the PNW.
| Research Publications | Publication Date |
|---|---|
| Baumbusch, RC, KM Dugger, and JD Wiens. 2023. Estimating fat content in barred owls (Strix varia) with predictive models developed from direct measures of proximate body composition. Conservation Physiology 11(1): coad069; doi:10.1093/conphys/coad069. | September 2023 |
| Presentations | Presentation Date |
|---|---|
| Thomas, H., R.C. Baumbusch, K.M. Dugger, and J.D. Wiens. 2020. Prey sharing between barred owls (Strix varia) in Oregon and Washington. 67th Annual Meeting of The Western Section of The Wildlife Society, February 3-7, 2020, Redding, CA. | February 2020 |
| Souza, S.A., R.C. Baumbusch, K.M. Dugger, and J.D. Wiens. 2020. Identification and quantification of Barred owl (Strix varia) intestinal parasites in the Pacific Northwest. 67th Annual Meeting of The Western Section of The Wildlife Society, February 3-7, 2020, Redding, CA. | February 2020 |
| Körner, L., R.C. Baumbusch, K.M. Dugger, and J.D. Wiens. 2020. Morphology of the barred owl (Strix varia) in the Pacific Northwest. 67th Annual Meeting of The Western Section of The Wildlife Society, February 3-7, 2020, Redding, CA. | February 2020 |
| Briggs, U.S.Y., R.C. Baumbusch, K.M. Dugger, and J.D. Wiens. 2020. Partial consumption of prey in barred owl (Strix varia) diets. 67th Annual Meeting of The Western Section of The Wildlife Society, February 3-7, 2020, Redding, CA. | February 2020 |
| Baumbusch, R.C., K.M. Dugger, and J.D. Wiens. 2020. Diet Composition of Barred Owls (Strix varia) in the Pacific Northwest. 67th Annual Meeting of The Western Section of The Wildlife Society, February 3-7, 2020, Redding, CA. | February 2020 |
| Baumbusch, R.C., K.M. Dugger, and J.D. Wiens. 2020. Body Condition of Barred Owls (Strix varia) in the Pacific Northwest. 67th Annual Meeting of The Western Section of The Wildlife Society, February 3-7, 2020, Redding, CA. | February 2020 |
| Theses and Dissertations | Publication Date |
|---|---|
| Baumbusch, Ryan C. 2023. Foraging ecology of barred owls where they are outcompeting the threatened Northern spotted owl. Ph.D. Dissertation, Oregon State University, Corvallis, OR, 149pp. | March 2023 |