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:


Photo from Wikimedia Commons by John and Karen Hollingsworth

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.”



  • If they’d stop chemtrailing, the owl might make a comeback. Blaming the decline on growers is silly, as much of Washington doesn’t have the climate condusive for humdumery.

    • You never seem to have a non convoluted actual point to your comments.

      Do you realize that you come across as a trollish half-wit?

    • It is important to distinguish between grow types. (Which admittedly we did not do a good job at. My bad.) Toxicant exposure associated with rodenticide from cannabis operations is generally linked to trespass cannabis grows as opposed to private cannabis grows. Obviously, dumping rodenticide in the middle of a national forest would have a greater impact to wildlife than in more rural residential settings. That said, please consider alternatives to rodenticides!

    • For a second, I laughed, then I felt really bad for you. You need to get some help.

    • Yeah and if we would start shooting them, then there would be none to count. Lame tree huggers have done ruined this country.

  • Time to start eating barred owls…..

  • My home is South of Pilsbury, East of Potter Valley, at 2800′ elevation. I saw my first Spotted Owl up here in 1993. Two of them sitting on a manzanita branch, 6 feet away at eye-level. They acted almost “tame.” Over years of hide-and-seek appearances, I am now almost certain to see them because I know where to look.
    Logging and Cannabis aside, is it possible their range is shifting because of Climate Change? Is there a site for reporting these encounters? (I have tried several “Google” recommendations, w/o success.)

    • Good question. I haven’t seen anything concerning expansion or contraction of the spotted owls’ range. (Although, if this were to happen, I imagine it would be at the northern end of the owls’ range.)

      Climate change is thought to affect spotted owls by changing weather patterns. Spotted owl fecundity and adult surival is impacted by cold and wet winters. At this point, I am not sure what the best climate models say for winter weather conditions within the range of the northern spotted owl. (Warmer but more precip? Less?)

      Dugger et al. (2015), the study referenced above, discusses weather’s impact to spotted owl demographics.

    • Keep your lip zipped

  • any update on the Barred Owls removal study?

    The Barred Owls had invaded SO territory.

    HSU professor was doing a study where both owls of the Barred Owls had to be removed…in this case shot.. A difficult decision, but the Barred Owls are tricky and persistent, as well as being more adaptable than the Spotteds..there are plenty of Barreds and their widely found across north American.

    • Dugger et al. (2015) reports some positive findings from the Green Diamond survey area, which showed that spotted owls recovery in areas of barred owl removal.

  • Hypocrisy abounds. So, the barred owl is a better adapted, more successful raptor than the spotted owl. And now, due to its ability to span environmental niches, it must be eliminated. Sounds like humans tampering with evolution to fulfill “environmentalist ” agendas.

    • To be clear, EPIC has not endorsed barred owl removal. That said, the study area in the Green Diamond study area, which is discussed in the Dugger et al. (2015) article, has shown promising results.

      The argument for barred owl removal, from an nuanced environmental perspective, goes like this:

      Northern spotted owl populations were already in decline, primarily from historic habitat loss. Barred owl invasion has essentially kicked the owl when it was already down, hastening the decline. To stem the bleeding, it may be necessary to do lethal barred owl removal. In doing so, the hope is that spotted owl populations can recover. As they recover, more habitat will also “come online” as a result of trees aging under the Northwest Forest Plan. There is some thought that barred owls and spotted owls can coexist, given enough high-quality spotted owl habitat. Thus, it may not be necessary to hunt barred owls forever to protect the spotted owl. Rather, a limited period of time may be necessary for spotted owls to recover.

      These situations are undoubtedly tricky and there doesn’t seem to be an easy answer.

  • No marijuana growing, no logging, but no mention of the 500,000 acres of forest that burned last summer?

  • The Lodge Fire of 2014 burned up mostly the upper South Fork Eel River watershed- from the top of Elkhorn Ridge to the top of Brush Mountain. This area is all wilderness that was specifically set aside because of its Northern Spotted Owl population and the Northwest Forest Plan. So…I agree- why no mention of the fires’ effects? I understand we are fighting extinction on all fronts- rodenticides from crappy growers, logging in sensitive habitat and warming climate with it’s increased fire events. Hope the owls can make it! Remember- the owls were recognized as an indicator species and so if we keep them around we are also keeping many other species that use the same environment. It’s about much more than these owls!!

    • Supposedly the spotted owl requires healthy, old growth forests for habitat. In my experience the fires in old growth, healthy forests are low intensity ground and understood burns. So, while certainly a disruption, these fires do not destroy the habitat of old growth dwellers.

    • The Lodge fire was a fairly healthy fire for the forest according to the scientists who assessed the area afterwards. It burned out the fuel build up and where it got hot and burned the crown the resulting spots with large trees that were killed promote biological diversity in the forests. The plants that thrive in the newly opened areas also support wood rats, the principal prey of SO’s in their southern range according to veteran spotted owl researcher Lowell Diller.

      A year afterwards as I stood on the ridge over Big Bend south of Leggett I could see little evidence of the fire on the forest. Very different from the disastrous Rim Fire near Yosemite where the fire was so intense that it sterilized the soil in large areas.

  • Hey all, there have been some great questions, particularly concerning fire and spotted owl habitat. A couple interesting points:

    First, spotted owl use of burned areas Most fires burn in a mixed, severity, producing a “mosaic” fire effect with patches of high-severity fire near patches of lowers severity. While high-severity fire likely downgrades spotted owl habitat from nesting/roosting habitat to foraging habitat, it is important to note that spotted owls still readily use high-severity areas for foraging. (The sudden pulse of dead wood is great for certain prey species, such as woodrats and field mice.) However, if the high-severity area is subsequently logged, then it removes all the complex structures (i.e., snags) that spotted owls use for perching and removes all habitat value for spotted owls. So after fires occur, it is important not to further the impact to owls by logging the high-severity patches.

    Second, low-severity fires is good for spotted owls in the long term. As I said above, most fires burned at a mixed-severity, with high, moderate, and low effects. Even in some of these LARGE fire events, like the 200,000 acre fire complex near Happy Camp in 2014, most areas burn in a low severity. Low-severity fire helps to hasten the creation of complex forest structures, such as broken tops, cavities, deformations, etc., that are associated with old-growth forests. In doing so, fire actually hastens the development of old-growth, on which the owl depends!

    As to impacts from cannabis cultivation, like with impacts to the threatened Pacific fisher (which has received most of the attention in regards to toxicant exposure), the source of rodenticide is generally thought to be from trespass cannabis grows, not private operations. Toxicant exposure is just one of numerous threats to the owl, including habitat loss, barred owl invasion, and climate change.

    • Tom, I disagree that rodenticide exposure is mostly from trespass grows on public lands and commercial timberlands. That’s just where the research is going on. Rodenticide exposure happens everywhere it is used in our area and that includes grows on private lands. Anyone who is using it is poisoning rodent predators, not just the charismatic Fishers and Spotted Owls. I’ve heard plenty of anecdotal stories from people who report fewer owl sightings over the past few years that coincide with the green rush, including me. Unfortunately research is spread thin and isn’t surveying large sections of privately owned watersheds where the bulk of the cannabis is being grown.

      Several years ago Lowell Diller told me that they were finding owls that tested for low levels of exposure, birds that were still active and feeding, but who may have not been healthy enough to nest and rear young.

  • Once again, I know a spot on the side of a private gravel road where I was dive bombed by an owl with white spots everywhere on its plumage. I hear the barred owl looks the same.
    I tried to interest some of our so called environmental talent to show them in person yet was told the odds of a spotted owl being in a second growth are was so low they refused to even look.

    • In the early 90’s I had a photo assignment to photograph spotted owl researcher Lowell Diller on what was then Simpson Timber property east of Korbel. The owls we found and the one he captured were all in maturing second growth forest.

      • My ex used to call certain stands “virgin second-growth” and I’m certain the owls find them completely satisfactory… except they’re at least as rare as virgin old growth.

      • A lot of that Cahto Wilderness on the South Fork Eel is second growth, with some remnant old growth stands. Part of the idea of preserving it was that since the second growth was last logged in the 50’s it could soon contain enough old-growth characteristics for the owl to nest. But they forage in mature 2nd growth. I see them in there. Studies show that they need the old-growth for nesting. Again, we can see the spotted owl easier than many of the species that it’s presence indicates. So if they are around you probably also have some red tree voles and an intact old-growth eco-system is miraculously somehow still surviving. Yay.

  • Im sure rodenticide is negatively affecting the spotted owl and we should be working to address that. That being said, the effects of cannabis on the spotted owl are like a drop in the ocean when compared to the MASSIVE deforestation of the Northwest.

  • I think the loss of its habitat due to man’s negligence, and climate changes has more to do with the demise of the owl right along side the fisher

  • This story is bad news. We have had plenty of Spotted Owl in the hills east of Piercy until just a year or so ago. I have heard as many as 5 or 6 calling during mating season, enjoy their cries year-round, and have seen two on different occasions chillin in the trees during summer. Now, seldom heard …

  • Quite the interesting conversation, thanks all.

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