Northern Spotted Owl Populations Are Rapidly Declining, A New Study Finds
The following is a press release from the Environmental Protection Information Center and the Washington Forest Law Center:
Washington, DC: The northern spotted owl is in decline across its entire range and its rate of decline is increasing—that is the conclusion of a major demographic study produced by federal scientists, published Wednesday, December 9, 2015, in the journal “The Condor.” The study examined survey results from monitoring areas across the range of the imperiled owl.
This research indicated that since monitoring began spotted owl populations declined 55–77 percent in Washington, 31–68 percent in Oregon and 32–55 percent in California. In addition, population declines are now occurring on study areas in southern Oregon and northern California that were previously experiencing little to no detectable decline through 2009.
“This study confirms that immediate action is needed to protect all remaining spotted owl habitat and to restore additional habitat by maintaining and expanding the successful reserve network of the Northwest Forest Plan,” said Tom Wheeler, program and legal coordinator with the Environmental Protection Information Center.
While habitat loss continues to threaten the owl, new threats have emerged. Barred owls, whose range has increased in recent years to coincide with the northern spotted owl, can outcompete the northern spotted owl for food and territory. Additionally, rodenticide use by illegal marijuana growing operations on federal lands is negatively impacting northern spotted owls, particularly in its southern range.
Implications of the New Study
Dr. Katie Dugger, a research biologist at the USGS Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University and lead author on the report, said that, “The amount of suitable habitat required by spotted owls for nesting and roosting is important because spotted owl survival, colonization of empty territories, and number of young produced tends to be higher in areas with larger amounts of suitable habitat, at least on some study areas.”
Much attention has turned to the increased threat posed by barred owls since the northern spotted owl’s listing. Kara Whittaker, PhD, Senior Scientist & Policy Analyst at the Washington Forest Law Center, stresses that adequate habitat is the only long-term solution to barred owls. “Science shows that spotted owls and barred owls can coexist where there is enough high-quality habitat. A large amount of owl habitat will become available if the Northwest Forest Plan is allowed to continue working to restore the old growth ecosystem. Preserving as much high-quality habitat as possible on nonfederal lands is also needed to support the coexistence of both species.”
The northern spotted owl is a rare raptor often associated with the complex features and closed canopy of mature or old-growth forests. As the owl is associated with older forests, the spotted owl serves as an “indicator species”—their presence indicating that the forest is healthy and is functioning properly. Historically, spotted owl decline is traced to habitat loss caused primarily by logging. Because the owl is dependent on older forest types, once a forest is logged it can take many decades before suitable habitat can regrow.
The northern spotted owl was listed as “threatened” under the federal Endangered Species Act in 1990. The listing intensified the already simmering tensions over federal forest management. As a consequence of overcutting of owl habitat and a failure by the land-management agencies to comply with wildlife protection requirements, logging of federal forests was largely halted across the range of the owl.
In reaction to the stalemate over federal forest management, in 1994, the Clinton Administration established the “Northwest Forest Plan,” a landscape-level resource management plan that established a series of forest reserves across the range of the northern spotted owl intended to both protect remaining owl habitat and to develop future habitat. After 20 years, U.S. Forest Service monitoring reports indicate the plan is working as intended and meeting its objectives to improve water quality and restore wildlife habitat; Northwest forests are also now storing carbon instead of being a source of emissions.
“The system of reserves has slowed the decline of the owl,” said Wheeler. “But the spotted owl’s continued decline makes clear that this reserve system is not enough to stabilize the population. All spotted owl habitat on federal land should be protected from logging.”