Spotted Owl

Strix occidentalis

Image by NASA
  • STRIGIDAE
  • Owls
  • Strigiformes
  • Búho Manchado
  • Chouette tachetée
Introduction

In the early 1980s, the Spotted Owl became the icon of conservation activism. Its old-growth haunts are very valuable to the logging industry, and vast forest tracts were clear-cut or otherwise exploited, leaving the owls homeless and their populations dwindling. Environmental groups used the owl's charisma in a public campaign to slow deforestation and to protect this owl, while also promoting environmental awareness.

Appearance Description
This medium-sized owl is mostly chocolate-chestnut brown and, as the name suggests, has round-oval white spots on its head, neck, back and underparts. The wings and tail are dark brown with lighter barring. The round head does not have "ear" tufts. Two large, round facial disks surround the brown eyes with a subtle pattern of dark, concentric circles. At night, this species can be identified by its call, consisting of a variety of low-pitched hoots, barks and whistles. Spotted Owls measure about 17.5 inches long with a 40-inch wingspan and weigh 1.3 pounds. Depending on the subspecies, females outweigh males by 10 to 14%.
Range Map
Courtesy Kenn Kaufman
Range Distribution
Three distinct subspecies of Spotted Owl range from Canada's British Columbia to Mexico's Michoacan State. The "California" Spotted Owl (Strix occidentalis occidentalis) is found in several mountain ranges throughout California. The "Northern" Spotted Owl (S. o. caurina) replaces the California subspecies in the northern part of that state, and its range extends north to British Columbia. The "Mexican" Spotted Owl (S. o. lucida) is found primarily in the Sierra Occidental in Mexico, north to New Mexico and Arizona, where it resides in several pockets of high-elevation forest.
Habitat
Year round, Spotted Owls rely upon coniferous forests in the late stage (i.e., old growth, 200+ years old) for hunting, nesting in the unique, cool microclimate that these forests provide. With complex and varied structures, large stands of hemlock, Douglas fir, true firs, ponderosa pine, and mixed forests of pine and oak are used. They sometimes hunt on the forest edge or in small clearings, but these owls generally avoid crossing clear-cuts and openings. Roosts are in thicker stands of trees, often near water. Spotted Owls in California are found more often in deciduous hardwoods, especially oaks, from sea level to 3,200 feet.
Feeding
The diet consists of medium-sized rodents, especially northern flying squirrels and dusky-footed woodrats, hunted between dusk and dawn. Other prey include brush rabbits, mice, pocket gophers, squirrels like Douglas and gray squirrels, voles, and many insects. Males and females probably hunt in slightly different habitats, in order to suit their size differences. Perching quietly, the owls ambush prey by diving on them with open talons. Climbing rodents can be plucked from branches. When prey are abundant, they may be stored temporally in a trees, rocks, or earthen hollows. Spotted Owls drink fresh water from streams and dripping rocks.
Reproduction
Spotted Owls form monogamous pair bonds that last many years, and they occupy the same home range together. In late winter or early spring, pairs begin to call and roost together. Like many other owls, Spotted Owls don't build a nest but instead use naturally occurring sites, 65 to 90 feet above ground, in tree holes, piles of leaves and sticks in a tree's crotch, large clumps of mistletoe, or the shelf of a cliff face. Old hawk or raven nests are also reused.

The female lays only one clutch of 2 - 3 whitish eggs and incubates them for about a month, while her mate feeds her. The downy white hatchlings are fairly helpless and blind. The female broods and feeds the young with items brought by the male. Owlets leave the nest in about 35 days and fly a few days later. Both parents tend the fledglings until September or October, when the full-grown young leave their parents' home range.
Migration
Spotted Owls are year-round residents in their range and are quite sedentary. The only significant movements occur when young disperse from their parents' territory or when the owls move during harsh winters to lower elevations, in order to find food. These temporary displacements cover 10 to 40 miles and represent drops in elevation between 1,600 and 4,800 feet.
  • 15,000
  • 15,000
  • Threatened
Population Status Trends
Over its entire range, the Spotted Owl has declined by an average 3.7% every year between 1985 and 2003. With an estimated 3,778 breeding pairs and 1,001 single birds in 1998, the Northern Spotted Owl is showing the greatest losses with annual declines of 7.1% from 1994 to 2004. In only 13 years (1990-2003), local populations in Washington and Oregon lost 40-60% of their total numbers. British Columbia's owls dwindled from an estimated 500 pairs before European settlement to 50 breeding pairs in 2001, 30 pairs in 2004, and as few as 25 individuals in 2007. The California Spotted Owl was recently estimated at 3,050 individuals. Several studies of this subspecies have indicated that it is in decline over much of its range. The 800-1,600 individual Mexican Spotted Owls may be declining slightly or holding stable.
Conservation Issues
The decline of the Spotted Owl has been caused largely by the destruction of old-growth forests for precious timber. Harvesting also isolates populations, limiting dispersal and potentially causing localized extirpation. Just such a loss is about to happen in British Columbia, where drastic, controversial measures were proposed in 2007 to save the only Canadian population. Between the early 1800's and 1990, the US Fish and Wildlife Service (USFWS) estimated that 60 to 88% of the Northern Spotted Owl's habitat was destroyed. From 1994 to 2003, the USFWS reported another 2.5% total loss of habitat on federal lands, due mostly to timber harvest. Losses on private lands were estimated at double that rate. During the same period, wildfires, insects, and disease claimed an additional 3% of suitable, publicly owned habitat. A new threat is the Barred Owl, which has been invading the Spotted Owl's northern range and displacing the slightly smaller and perhaps less aggressive species.

In 1990 the USFWS listed the Northern Spotted Owl as Threatened, and Mexico also recognizes the Mexican Spotted Owl as Threatened. Canada upgraded it to Endangered in 2002, with a plan in 2007 to capture all or most of the remaining wild owls for a breeding program and eventual release. In 2006, the USFWS declined to list the California Spotted Owl through the Endangered Species Act, citing a stable population (a disputed claim) and programs in place for reducing the threat of wildfire.

The development of comprehensive plans that all parties can agree upon is challenging. For example, the U.S. Draft Recovery Plan for the Northern Spotted Owl (April 2007) shifts the management emphasis from habitat protection and recovery to containment of the Barred Owl. Just a month later, the USFWS used the Plan to propose cutting the owl's Critical Habitat by more than 1.5 million acres, a 22.5% reduction. Three separate peer reviews – by the American Ornithologists' Union, Society for Conservation Biology, and The Wildlife Society – released in August of 2007 agreed that the U.S. plan did not use the best available science and undermines the survival of the subspecies. A member of the Canadian Team resigned in 2007, when he learned of the plan to capture all of Canada's remaining Spotted Owls.
What You Can Do
Look for the Spotted Owl in an Important Bird Area like the Siuslaw National Forest near Corvallis, Oregon, or the Lincoln National Forest near Alamogordo, New Mexico. The Yosemite Birding Festival, held each year
over the first weekend in May, sometimes provides an expert guide to find Spotted Owls in Yosemite National Park.

Listing of the Spotted Owl under the Endangered Species Act has made it possible to learn critical information about the biology of the species. Audubon continues to work to ensure that this vital legislation is being used to protect our publicly owned wildlife resources. Audubon's Issues & Actions web page reviews the latest news about the Endangered Species Act and suggests how you can help.

The Sierra Madre Alliance is an organization that works with many groups in the Sierra Madre Occidental to ensure the old-growth forests and the many organisms and indigenous tribes that rely on them can be preserved.

Find out about actions you can take including Audubon programs and activities.
More Information
Learn more about this species and other birds through these resources.
Natural History References
Gutierrez, R.J.; Franklin, A.B.; Lahaye, W.S. 1995. Spotted Owl (Strix occidentalis). The Birds of North America, No. 179 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D. C.

Sibley, David Allen. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.
Conservation Status References
Fenger, Mike, et al. Northern Spotted Owl Population Enhancement and Recovery in British Columbia: Proposed Five-Year Action Plan. March 2007. Ministry of the Environment, British Columbia, Canada. Accessed 26 July 2007. 

Gutierrez, R.J.; Franklin, A.B.; Lahaye, W.S. 1995. Spotted Owl (Strix occidentalis). The Birds of North America, No. 179 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D. C.

Lint, Joseph, tech. coord. 2005. Northwest Forest Plan—the first 10 years (1994––2003): status and trends of northern spotted owl populations and habitat. General Technical Report: PNW-GTR-648. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 176 pages. Accessed 22 July 2007.

Livezey, Kent. "12-month Finding for a Petition to List the California Spotted Owl (Strix occidentalis occidentalis) as Threatened or Endangered." Federal Register: May 24, 2006 (Volume 71, Number 100). Fish and Wildlife Service, Interior. Accessed 25 July 2007.