U.S. Fish & Wildlife Service

Sacramento Fish & Wildlife OfficeServing the people, conserving the fish, wildlife, and plants of California

A Unit Of The Pacific Southwest Region

Species Information

Photo of California Spotted Owl

Photo Credit: Tim Demers

California Spotted Owl

Strix occidentalis occidentalis

Basic Species Information

STATUS

The California spotted owl has been petitioned for listing and is currently under review. The U.S. Fish and Wildlife Service (Service) completed a positive 90-day finding on September 18, 2015. The listing decision is due by September 30, 2019.

DESCRIPTION

The spotted owl is a medium-sized brown owl with a mottled appearance – white spots on the head and breast, and a barred tail. It has dark brown eyes surrounded by prominent facial disks. California spotted owls are one of three subspecies of spotted owl. The other two subspecies are northern spotted owl and Mexican spotted owl.

FOOD SOURCES

California spotted owls are small mammal specialists. While they eat a diversity of prey, the majority of their diet consists of a few key species: northern flying squirrels (at higher elevations) and woodrats (at lower elevations).

HABITAT

California spotted owls generally inhabit older forests that contain structural characteristics necessary for nesting, roosting, and foraging. Nests are typically found in areas of high canopy cover, with a multi-layered canopy, old decadent trees, a high number of large trees, and coarse downed woody debris. Within an owl territory, spatial heterogeneity to some degree is important for foraging habitat. About ¾ of known California spotted owl locations are on public lands (e.g., National Forests), with the remaining on private timberlands.

MATING

Spotted owls form monogamous pairs, and each pair defends a territory surrounding a nesting and/or roosting site. Breeding typically begins in mid-February, and the female lays an average of two eggs. Pairs divide the nesting roles – the male provides the female with food while she incubates the nest. Nests in the Sierras are most often cavities, but spotted owls can also use broken top trees or platform nests. Spotted owls do not typically nest every year, and nesting is highly dependent on weather conditions prior to and during the breeding season.

RANGE

The California spotted is continuously distributed throughout the forests of the western Sierra Nevada mountains, from Shasta County south to the Tehachapi Pass. There is a gap in the distribution south of the Sierras, and California spotted owls again occur in southern and central coastal California. Just north of Lassen Peak to south of the Pit River, the range of California spotted owl transitions into that of the northern spotted owl.

PREDATORS

Although predation is not a strong driver of spotted owl populations, some predators can include great horned owls, northern goshawks, and red-tailed hawks.

STRESSORS

Long-term studies of California spotted owls in National Forests indicate that the populations are in decline. Recent research suggests that past habitat loss due to removal of large trees and fire suppression may have partly contributed to the declines. One population studied in Sequoia-Kings Canyon National Park appears to be stable. Habitat loss due to large, high-severity fires and large-scale tree mortality from drought and bark beetle impacts, as well as some types of forest management practices including fuels reduction activities, salvage logging, and timber harvest may adversely affect the California spotted owl. A prominent emerging stressor for California spotted owl is the southern expansion of the barred owl, which has been a significant stressor for the northern spotted owl within its range. Additionally, contaminants, primarily rodenticides from illegal marijuana cultivations, may also affect spotted owls. Climate can alter reproduction patterns and worsen large, high-severity fires and drought.

CONSERVATION EFFORTS

California spotted owls would benefit from preservation of high quality habitat throughout their range and reducing the likelihood of large, high-severity fires. Historically, California spotted owls persisted with a natural fire regime. Low to moderate and mixed severity fires can be beneficial to owl habitat; however large, high-severity fire may remove important habitat. The Service is working proactively with partners, such as the U.S. Forest Service and private landowners, to develop conservation actions, including:

Last updated: May 1, 2019