Center for Biological Diversity

Protecting endangered species and wild places through
science, policy, education, and environmental law.


Contact: Jeff Miller (510) 625-0136, Center for Biological Diversity
Craig Breon (408) 252-3748, Santa Clara Valley Audubon Society
Kim Delfino (916) 313-5809, Defenders of Wildlife
More Information: Burrowing Owl Web,

A coalition of conservation groups, birders, and state park rangers today formally petitioned the California Fish and Game Commission to list the western burrowing owl (Athene cunicularia hypugaea) as a state endangered or threatened species under the California Endangered Species Act. Burrowing owls have declined precipitously in California in the last two decades - breeding owls have been eliminated from at least 8-10% of their former range in the state and are trending toward extinction in another 25%. The groups petitioning for the once-common owl are the Center for Biological Diversity, Santa Clara Valley Audubon Society, Defenders of Wildlife, San Bernardino Valley Audubon Society, California State Park Rangers Association, and Tri-County Conservation League.

"Despite their adaptability, burrowing owls have been continuously shoved aside and their habitat destroyed by development," said Jeff Miller, spokesperson for the Center for Biological Diversity. "Without formal protection for burrowing owls, we face the unhappy prospect that the species will soon disappear from all rapidly urbanizing areas of the state and indeed most of their range."

"Audubon chapters and other conservationists throughout the state have been fighting a losing battle against development projects for decades in an attempt to protect these owls," said Craig Breon, Executive Director of the Santa Clara Valley Audubon Society. "We need the formal protection listing the species will provide to turn that trend around," added Breon.

The western burrowing owl is a small ground-nesting bird of prairie and grassland habitats. Burrowing owls in California rely upon burrows dug by ground squirrels for nests, and require suitable habitat consisting of open fields with adequate food supply for foraging, low vegetative cover to allow owls to watch for predators, and roosting sites.

Many early accounts of the burrowing owl reported the species was one of the most common birds in California. Burrowing owls historically ranged throughout the Central Valley, were found in suitable habitat in coastal areas from Marin County south to the Mexican border, and in sparsely inhabited desert areas in northeastern and southeastern California. Since at least the 1940s owls have been in continuous decline throughout the state. Burrowing owls are threatened primarily by habitat loss to urban development and eradication of ground squirrels and other burrowing rodents. The state-approved practice of relocation of owls from development sites is accelerating local extirpations from rapidly urbanizing areas.

Surveys conducted throughout most of California during the early 1990s documented a nearly 60% loss in the number of breeding owl colonies known from the 1980s, and a decline in overall population numbers by 8% per year. It was thought that an estimated 9,450 breeding pairs of owls remained statewide at that time. Breeding owls have recently been completely eliminated from 5 counties (Napa, Marin, San Francisco, Santa Cruz, and Ventura) and are nearing extirpation in at least 6 others (Sonoma, San Mateo, Monterey, San Luis Obispo, Santa Barbara, and Orange). Breeding owls are rapidly disappearing from southern Los Angeles, western San Bernardino, western Riverside, and San Diego Counties as well.

While burrowing owl populations are declining in urban areas, densities of owls in some areas of the state have increased with intensive agriculture, such as in the Imperial Valley, southern Central Valley, and lower Colorado River Valley. Over 71% of California's breeding owls currently live in the margins of agricultural land in the Imperial Valley, an area that comprises only 2.5% percent of the land area of the state. Owls in the Imperial Valley, which primarily nest in burrows in earthen irrigation channels, are facing threats from conversion of agricultural lands to urban development, plans to line earthen canals with concrete, and ground squirrel eradication programs. Over 15% of the state's breeding owls reside in the southern Central Valley, an area undergoing explosive human population growth and rapid conversion of agricultural lands to urban development.

"Although intensive agriculture can impact individual owls, the apparent coexistence of burrowing owls with agriculture in the Imperial and southern Central Valleys indicates that current agricultural practices are not a significant threat. The real threat to owls is the loss of habitat and agricultural lands from rampant urban development," said Kim Delfino, Defenders of Wildlife.

Other factors contributing to the decline of owls statewide include destruction of burrows through disking and grading, impacts of pesticides, increased predation by non-native or feral species, habitat fragmentation, and other human-caused mortality from vehicle strikes, electrified fences, collisions with wind turbines, shooting, and vandalism of nesting sites.

There are currently no state or federal laws that protect owl habitat and such habitat is rarely purchased by agencies to conserve the owl and other grassland-dependent species. An estimated 91% of all owls remaining in California occur on private land, much of which is threatened by future development. Although federally designated as a Species of Special Concern in 1994, federal regulatory mechanisms such as Habitat Conservation Plans have proved inadequate in protecting significant owl habitat or stopping the rapid decline of the species. State regulatory mechanisms, such as designation as a state Species of Special Concern in 1979, adoption of burrowing owl mitigation guidelines by the California Department of Fish and Game in 1995, state Fish and Game Codes protecting nesting raptors, and limited creation of mitigation banks to purchase habitat, have proved unsuccessful in protecting the burrowing owl and its habitat.

Throughout the vast majority of the burrowing owl's range in California, breeding owls persist in only small, declining populations of birds that are highly susceptible to extirpation. The burrowing owl is in imminent danger of becoming extinct throughout a significant portion of its range in California, and requires immediate protection as an endangered or threatened species.

The western burrowing owl has declined significantly throughout its range in North America and is listed as endangered in Canada in which it breeds and threatened in Mexico. The majority of the mid-western and western states within the owl's range have listed the species: it is state-listed as endangered in Minnesota and Iowa, threatened in Colorado, and as a state Species of Special Concern in Kansas, Nebraska, Oklahoma, South Dakota, North Dakota, Montana, Idaho, Utah, Washington, Oregon, and California. California supports the largest remaining breeding and wintering populations of the species.

To view the listing petition, download photographs of the burrowing owl, or for further information visit:
The Center for Biological Diversity is a nonprofit environmental organization dedicated to the protection of native species and their habitats. The Center works to protect and restore natural ecosystems and imperiled species through science, education, policy, and environmental law.

The Santa Clara Valley Audubon Society works to maintain, preserve, and protect native animal and plant habitats and to foster a greater public awareness of our environment, with emphasis on birds and their ecosystems, particularly in Santa Clara County and the San Francisco Bay Area.

Defenders of Wildlife is a nonprofit organization dedicated to the protection of all native wild animals and plants in their natural communities. Defenders programs encourage protection of entire ecosystems and interconnected habitats while protecting predators that serve as indicator species for ecosystem health.

The San Bernardino Valley Audubon Society is a non-profit corporation dedicated to conserving and restoring natural ecosystems, focusing on birds and other wildlife for the benefit of humanity and the earth's biological diversity.

The California State Park Rangers Association is an organization of park professionals dedicated to advancement of the highest principles of public service, established to support and preserve California State Parks for present and future generations.

The Tri-County Conservation League, Inc. is a public interest corporation with a membership that promotes the educational, recreational and conservation values of the natural resources of the Santa Ana River and its drainage system in Riverside, San Bernardino, and Orange Counties.


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