The Threatened Spotted Owl

Northern Spotted Owl, Coast Range, Oregon.
Northern Spotted Owl, Coast Range, Oregon. Danita Delimont / Getty Images

Many western states have experienced swirling controversy centered on the spotted owl, probably more so than with any other bird species. Its soft hoots still echo in the shaded hills for now, but the number of spotted owls continues to dwindle.

Ecology

The spotted owl is a rich brown, medium size owl with creamy white spots. It ranges from coastal British Columbia, Canada, through the coastal states of the western United States, across the US southwest and southern Rockies, and in the mountains of Mexico.

Its prey base consists in small mammals, most notably flying squirrels and woodrats.

Over most of their range, spotted owls are associated with conifer forests made of old, large trees. The tree species composition depends on what is available locally, and it includes Douglas-fir, redwood trees, western hemlock, and Ponderosa pine. Spotted owls can even be found in the shade of oaks and sycamores deep in southwestern desert canyons.

A Protected Species

Three subspecies are recognized: the northern, California, and Mexican spotted owls. Since the early 1990s both the northern and Mexican subspecies have been listed under the Endangered Species Act as threatened and carry a protected status in the states and provinces where they are found. The U.S. Fish & Wildlife Service is under pressure to also list the California subspecies, which is found mainly in the Sierra Nevada range.

The latest estimates report a total population size of around 15,000 adults, about half of which are of the northern subspecies.

The decline in population is estimated to be around 3% a year, higher for the populations in Washington and British Columbia. The Canadian population is probably down to no more than a few dozen individuals now.

Spotted Owls as an Umbrella Species

Because of its exclusive association with old conifer forests, the northern spotted owl is considered an umbrella species: when its habitat is protected, many other less charismatic species living in the same forests get protected as well.

For example, the Pacific fisher, the red tree vole, and the Del Norte salamander all depend on the same coastal forests in Oregon and California.

Threats to the Spotted Owl

Because its habitat requirements are closely tied to old growth coniferous forest, especially in the case of the northern subspecies, everything that affects the forests’ integrity is a threat to the owl. Suburban sprawl consumed substantial amounts of forest, and the development of logging and mining roads further drove habitat fragmentation. The impacts of forestry on spotted owl habitat have been the subject of intense scientific scrutiny in the last few decades, and a complex picture is emerging. Clear cuts have a detrimental effect, but the owls will use some cut-over areas for hunting, before retreating to large trees for roosting. Although they show a preference for old growth forest, spotted owls seem to return to areas that have been logged several decades prior, but it may take as much as 60 or 70 years for that to occur.

Another threat has been putting pressure on the northern spotted owl subspecies, this time coming from the east. A close species, the barred owl, has been expanding its range westward and has started to mingle with its spotted cousin.

The bigger, more aggressive barred owl out-competes spotted owls in terms of hunting territories and prey items. The barred owl population is secure, so conservation agencies and land managers in California and Oregon have made the difficult decision to kill dozens of barred owls in an experiment, with the hope of seeing a positive response from the local spotted owls.

Protection and Controversial Consequences

The northern spotted owl exists at the heart of a region that had long been bustling with logging equipment and saw mills. However, the forest products industry in the Pacific Northwest has been experiencing a long decline due to a multitude of factors, including market globalization, automated technologies, and according to some observers, increased environmental regulations aimed at protecting natural resources like salmon, the spotted owl, and the marbled murrelet (a forest-nesting seabird).

The respective share of blame for all these factors is hotly debated, but the fact remains that the fraction of high-value old growth forest left is now very small, a situation felt painfully by both those working in the timber industry and by the animals relying on those habitats.

Sources

Center for Biological Diversity. Northern Spotted Owl.

IUCN Red List of Threatened Species. Strix occidentalis.

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Beaudry, Frederic. "The Threatened Spotted Owl." ThoughtCo, Jan. 17, 2017, thoughtco.com/the-threatened-spotted-owl-4122177. Beaudry, Frederic. (2017, January 17). The Threatened Spotted Owl. Retrieved from https://www.thoughtco.com/the-threatened-spotted-owl-4122177 Beaudry, Frederic. "The Threatened Spotted Owl." ThoughtCo. https://www.thoughtco.com/the-threatened-spotted-owl-4122177 (accessed January 20, 2018).