Progress Report - Effects of Experimental Removal of Barred Owls on Population Demography of Northern Spotted Owls

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Evidence suggests that the long-term persistence of northern spotted owls may be in question without additional management intervention.

In 2015, USGS scientists implemented an experiment on two study areas in Oregon and Washington to determine if removing barred owls can improve population trends of spotted owls located in the same area. A USGS report published in May, 2018 provides an overview of research accomplishments and results from 2017. The report includes survey results of both barred and northern spotted owls before barred owl removal occurred, as well as results of barred owl removals. Authors also include a timeline that documents project goals by year through anticipated project completion in January of 2019. The experiments provide a definitive test of whether competitive interactions with barred owls cause population declines of spotted owls, and if so, whether localized removal of barred owls is an effective tool to consider in long-term management and conservation of spotted owls.

Wiens, J.D., Dugger, K.M., Lesmeister, D.B., Dilione, K.E., Simon, D.C., 2018, Effects of experimental removal of barred owls on population demography of northern spotted owls in Washington and Oregon - 2017 progress report: U.S. Geological Survey Open-File Report, p. 23, https://doi.org/10.3133/ofr20181086.

 

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Date published: January 8, 2018
Status: Active

Effects of Experimental Removal of Barred Owls on Population Demography of Northern Spotted Owls in the Pacific Northwest

Barred owls (Strix varia) have expanded their geographic range from eastern to western North America, and their newly expanded range now completely overlaps that of the federally threatened northern spotted owl (S. occidentalis caurina; Gutiérrez et al. 2007, Livezey 2009,...