Threat of Invasive Barred Owls to Northern Spotted Owls and their Habitats Active
As an apex predator and fiercely territorial invader, barred owls at high densities have the potential to affect a variety of native wildlife through competition, niche displacement, and predation. Such impacts may be especially problematic for conservation of the federally threatened northern spotted owl, whose populations have continued to decline despite widespread protection of old forest habitat for the owl and associated wildlife. We conduct research to address the implications of the barred owl range expansion to conservation of northern spotted owls and other native wildlife in the Pacific Northwest. We work closely with resource managers to provide information on the status and ecology of barred owls, their role in population declines of northern spotted owls, and effectiveness of management options.
Current and Recent Studies
Effects of Barred Owls on Population Demography of Spotted Owls
A clear understanding of how competition with newly established barred owls contributes to population declines of northern spotted owls is required to inform potential control, mitigation, and recovery strategies. In collaboration with US Fish & Wildlife Service we are using large-scale field experiments to determine whether removing barred owls from select areas can improve population trends of northern spotted owls. This research will provide a definitive answer to whether competition with barred owls is contributing to population declines of spotted owls, and if so, whether control of barred owl numbers is an ecologically practical and cost-effective management tool to consider in future conservation strategies for spotted owls. Please visit the USGS project website here.
Collaborators: U.S. Fish and Wildlife Service, Oregon State University, Colorado State University, The Hoopa Tribe, California Academy of Sciences
Predator-prey Interactions of a Non-native Raptor
Little research exists on the overall impacts of the barred owl, a newly established apex predator in the Pacific Northwest, on other forest species, besides spotted owls, and food-web dynamics. This project takes 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 Pacific Northwest forests. 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 these forests.
Collaborators: U.S. Fish and Wildlife Service
Anticoagulant Rodenticide Risk to Pacific Northwest Predators
Contamination of nontarget wildlife by anticoagulant rodenticides is a global conservation concern. Recent studies in remote forests of California have shown anticoagulant rodenticide contamination of the food web and transfer to sensitive forest predators, including the federally threatened northern spotted owl. The USGS is leading a team of scientists that are using barred owl carcasses to test if anticoagulant rodenticides pose a risk to the spotted owl and other old-forest wildlife in the Pacific Northwest. For information on a recent publication, click here.
Collaborators: U.S. Fish and Wildlife Service, Bureau of Land Management, U.S. Forest Service, University of California at Davis
Competitive Interactions and Resource Use
Understanding the competitive relationship between spotted owls and barred owls requires primary information on individual life-history traits, resource use, and population dynamics. This research investigates the distribution, habitat associations, diets, and demography of barred owls and spotted owls so that the potential mechanisms and consequences of interspecific competition can be identified and addressed within a management context.
Collaborators: U.S. Fish and Wildlife Service, U.S. Forest Service, National Park Service, Bureau of Land Management, Oregon Department of Forestry, Oregon State University, Boise State University, Colorado State University
Survey and Monitoring Tools for Barred Owls
Most information on occurrence and distribution of barred owls in the Pacific Northwest is limited to ancillary data from studies of spotted owls. Our research addresses this shortcoming by developing, testing, and implementing survey designs that allow researchers and land managers to monitor occurrence and distribution of barred owls with high confidence.
Collaborators: U.S. Fish and Wildlife Service, U.S. Forest Service, Oregon State University
Conservation Genetics of Spotted Owls
The USGS has been collecting and analyzing information about spotted owl genetics for decades. Management agencies use these and other genetic information to review the status of the northern spotted owl, and in combination with population estimates and habitat assessments, to consider management options for all three subspecies - California, northern, and Mexican - of spotted owl and their hybrids.
Collaborators: U.S. Fish and Wildlife Service, U.S. Forest Service, Oregon State University
Below are other science projects associated with this project.
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Northern spotted and barred owl pics.
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
The relationship between habitat characteristics and demographic performance of northern spotted owls in southern Oregon
Modeling of site occupancy dynamics for northern spotted owls, with emphasis on the effects of barred owls
Subspecific relationships and genetic structure in the spotted owl
Modeling demographic performance of northern spotted owls relative to forest habitat in Oregon
Genetic identification of spotted owls, barred owls, and their hybrids: Legal implications of hybrid identity
Geographic variation and genetic structure in Spotted Owls
Demography of Northern Spotted Owls in southwestern Oregon
Resting metabolic rate of golden eagles, bald eagles, and barred owls harnessed with a tracking transmitter or an equivalent load
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- Overview
As an apex predator and fiercely territorial invader, barred owls at high densities have the potential to affect a variety of native wildlife through competition, niche displacement, and predation. Such impacts may be especially problematic for conservation of the federally threatened northern spotted owl, whose populations have continued to decline despite widespread protection of old forest habitat for the owl and associated wildlife. We conduct research to address the implications of the barred owl range expansion to conservation of northern spotted owls and other native wildlife in the Pacific Northwest. We work closely with resource managers to provide information on the status and ecology of barred owls, their role in population declines of northern spotted owls, and effectiveness of management options.
Current and Recent Studies
Effects of Barred Owls on Population Demography of Spotted Owls
A clear understanding of how competition with newly established barred owls contributes to population declines of northern spotted owls is required to inform potential control, mitigation, and recovery strategies. In collaboration with US Fish & Wildlife Service we are using large-scale field experiments to determine whether removing barred owls from select areas can improve population trends of northern spotted owls. This research will provide a definitive answer to whether competition with barred owls is contributing to population declines of spotted owls, and if so, whether control of barred owl numbers is an ecologically practical and cost-effective management tool to consider in future conservation strategies for spotted owls. Please visit the USGS project website here.
Collaborators: U.S. Fish and Wildlife Service, Oregon State University, Colorado State University, The Hoopa Tribe, California Academy of Sciences
Predator-prey Interactions of a Non-native Raptor
Little research exists on the overall impacts of the barred owl, a newly established apex predator in the Pacific Northwest, on other forest species, besides spotted owls, and food-web dynamics. This project takes 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 Pacific Northwest forests. 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 these forests.
Collaborators: U.S. Fish and Wildlife Service
Anticoagulant Rodenticide Risk to Pacific Northwest Predators
Contamination of nontarget wildlife by anticoagulant rodenticides is a global conservation concern. Recent studies in remote forests of California have shown anticoagulant rodenticide contamination of the food web and transfer to sensitive forest predators, including the federally threatened northern spotted owl. The USGS is leading a team of scientists that are using barred owl carcasses to test if anticoagulant rodenticides pose a risk to the spotted owl and other old-forest wildlife in the Pacific Northwest. For information on a recent publication, click here.
Collaborators: U.S. Fish and Wildlife Service, Bureau of Land Management, U.S. Forest Service, University of California at Davis
Competitive Interactions and Resource Use
Understanding the competitive relationship between spotted owls and barred owls requires primary information on individual life-history traits, resource use, and population dynamics. This research investigates the distribution, habitat associations, diets, and demography of barred owls and spotted owls so that the potential mechanisms and consequences of interspecific competition can be identified and addressed within a management context.
Collaborators: U.S. Fish and Wildlife Service, U.S. Forest Service, National Park Service, Bureau of Land Management, Oregon Department of Forestry, Oregon State University, Boise State University, Colorado State University
Survey and Monitoring Tools for Barred Owls
Most information on occurrence and distribution of barred owls in the Pacific Northwest is limited to ancillary data from studies of spotted owls. Our research addresses this shortcoming by developing, testing, and implementing survey designs that allow researchers and land managers to monitor occurrence and distribution of barred owls with high confidence.
Collaborators: U.S. Fish and Wildlife Service, U.S. Forest Service, Oregon State University
Conservation Genetics of Spotted OwlsThe USGS has been collecting and analyzing information about spotted owl genetics for decades. Management agencies use these and other genetic information to review the status of the northern spotted owl, and in combination with population estimates and habitat assessments, to consider management options for all three subspecies - California, northern, and Mexican - of spotted owl and their hybrids.
Collaborators: U.S. Fish and Wildlife Service, U.S. Forest Service, Oregon State University
- Science
Below are other science projects associated with this project.
- Data
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
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Northern spotted and barred owl pics.
No results found. - Publications
If you are unable to access a product or publication online, you can request a copy by sending an email with your contact information and the publication's citation to fresc_outreach@usgs.gov or call (541) 750-1030.
Filter Total Items: 32The relationship between habitat characteristics and demographic performance of northern spotted owls in southern Oregon
We used data from Northern Spotted Owl (Strix occidentalis caurina) territories to model the effects of habitat (particularly intermediate-aged forest stand types), climate, and nonhabitat covariates (i.e., age, sex) on owl reproductive rate and apparent survival in southwestern Oregon. Our best model for reproductive rate included an interaction between a cyclic, annual time trend and male breediAuthorsKatie M. Dugger, Frank Wagner, Robert G. Anthony, Gail S. OlsonModeling of site occupancy dynamics for northern spotted owls, with emphasis on the effects of barred owls
Northern spotted owls (Strix occidentalis caurina) have been studied intensively since their listing as a threatened species by the U.S. Fish and Wildlife Service in 1990. Studies of spotted owl site occupancy have used various binary response measures, but most of these studies have made the assumption that detectability is perfect, or at least high and not variable. Further, previous studies didAuthorsGail S. Olson, Robert G. Anthony, Eric D. Forsman, Steven H. Ackers, Peter J. Loschl, Janice A. Reid, Katie M. Dugger, Elizabeth M. Glenn, William J. RippleSubspecific relationships and genetic structure in the spotted owl
Hierarchical genetic structure was examined in the three geographically-defined subspecies of spotted owl (Strix occidentalis) to define relationships among subspecies and quantify variation within and among regional and local populations. Sequences (522 bp) from domains I and II of the mitochondrial control region were analyzed for 213 individuals from 30 local breeding areas. Results confirmed sAuthorsSusan M. Haig, E.D. Forsman, Thomas D. MullinsModeling demographic performance of northern spotted owls relative to forest habitat in Oregon
Northern spotted owls (Strix occidentalis caurina) are known to be associated with late-successional forests in the Pacific Northwest of the United States, but the effects of habitat on their demographic performance are relatively unknown. We developed statistical models relating owl survival and productivity to forest cover types within the Roseburg Study Area in the Oregon Coast Range of Oregon,AuthorsGail S. Olson, Elizabeth M. Glenn, Robert G. Anthony, Eric D. Forsman, Janice A. Reid, Peter J. Loschl, William J. RippleGenetic identification of spotted owls, barred owls, and their hybrids: Legal implications of hybrid identity
Recent population expansion of Barred Owls ( Strix varia) into western North America has led to concern that they may compete with and further harm the Northern Spotted Owl ( S. occidentalis caurina), which is already listed as threatened under the U.S. Endangered Species Act (ESA). Because they hybridize, there is a legal need under the ESA for forensic identification of both species and their hyAuthorsSusan M. Haig, Liv Wennerberg, Thomas D. Mullins, E.D. Forsman, P. TrailGeographic variation and genetic structure in Spotted Owls
We examined genetic variation, population structure, and definition of conservation units in Spotted Owls (Strix occidentalis). Spotted Owls are mostly non-migratory, long-lived, socially monogamous birds that have decreased population viability due to their occupation of highly-fragmented late successional forests in western North America. To investigate potential effects of habitat fragmentationAuthorsSusan M. Haig, R.S. Wagner, E.D. Forsman, Thomas D. MullinsDemography of Northern Spotted Owls in southwestern Oregon
Northern Spotted Owls (Strix occidentalis caurina) are associated with lower elevation, commercially valuable, late-successional coniferous forests in the Pacific Northwest. Meta-analyses of demographic parameters indicate that Northern Spotted Owl populations are declining throughout their range (Anderson and Burnham 1992, Burnham et al. this volume). Recent research has attempted to determine whAuthorsCynthia J. Zabel, Susan E. SalmonsResting metabolic rate of golden eagles, bald eagles, and barred owls harnessed with a tracking transmitter or an equivalent load
No abstract available.AuthorsJ.A. Gessaman, M.R. Fuller, P.J. Pekins, G.E. Duke - News
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