The Washington, Oregon, and California population of the marbled murrelet was federally listed as threatened in 1992. Currently, the U.S. Fish and Wildlife Service is proposing to revise its 1996 designation of critical habitat.

Historical Status and Current Trends

The North American subspecies of marbled murrelet ranges from the Aleutian Islands and southern Alaska south to central California, the largest portion of the population occurs in Alaska and British Columbia. Due to loss of older forests used for nesting sites, the species is declining. For example, current estimates indicate that the population has declined by 50 percent to 80 percent; approximately 6,500 individual murrelets inhabit the area along the coast of California. Using known population numbers relative to remaining suitable nesting habitat, it has been estimated that historically, 60,000 marbled murrelet pairs may have been found in this same area. Along the Oregon coast, recent surveys have shown a decline in murrelet numbers during the 1990s. Loss of viable nesting habitat is thought to be a primary factor responsible for an estimated annual 4 percent to 7 percent decline in marbled murrelet populations in Washington, Oregon, and California. It is unlikely that population numbers will increase rapidly due to the naturally low reproductive rate and the continued loss of nesting habitat indicates that the recovery of the species is likely to take decades.

Habitat

The marbled murrelet is a small, robin-sized, diving seabird that feeds primarily on fish and invertebrates in near-shore marine waters. It spends the majority of its time on the ocean, roosting and feeding, but comes inland up to 80 kilometers (50 miles) to nest in forest stands with old growth forest characteristics. These dense shady forests are generally characterized by large trees with large branches or deformities for use as nest platforms. Murrelets nest in stands varying in size from several acres to thousands of acres. However, larger, unfragmented stands of old growth appear to be the highest quality habitat for marbled murrelet nesting. Nesting stands are dominated by Douglas fir in Oregon and Washington and by old-growth redwoods in California.

Life History

Marbled murrelets nest from mid-April to late September. The sexually mature adult murrelet (at age 2 or 3 of an average 15-year lifespan) generally lays a single egg on a mossy limb of an old-growth conifer tree. Both sexes incubate the egg in alternating 24-hour shifts for 30 days. Murrelet chicks are virtually helpless at hatching and rely on the adults for food. The adults feed the chick at least once per day, flying in (primarily at dawn and dusk) from feeding on the ocean, carrying one fish at a time. The young fledge from the nest in about 28 days and appear to fly directly to the sea upon leaving the nest. Marbled murrelets have a naturally low reproductive rate because they lay only one egg per nest and not all adults nest every year.

Reasons for Decline

The primary cause of marbled murrelet population decline is the loss and modification of nesting habitat in old growth and mature forests through commercial timber harvests, human-induced fires, and land conversions, and to a lesser degree, through natural causes such as wild fires and wind storms. In general, forest management practices that maximize timber production cut and replant forest stands every 40 to 60 years. Since it takes 100 to 250 years to grow marbled murrelet nesting habitat, this time frame frequently does not allow old-growth characteristics to develop, thus eliminating large areas from providing future nesting habitat. Continued harvest of old growth and mature forests also perpetuates the loss and fragmentation of remaining habitat. Changing the existing habitat by fragmenting the forest into small patches of suitable habitat surrounded by open space also affects the habitat quality. Increased forest fragmentation can reduce nesting success by allowing increased predation of nests by raptors (great horned owls, sharp-shinned hawks, peregrine falcons) and corvids (jays, ravens, crows). In the murrelet's marine habitat, oil spills and gill-net fishing also threaten the population. Recent oil spills off the coast of California and Oregon have contributed to direct mortality of marbled murrelets and other seabirds.

Conservation Measures

Although most murrelet nesting habitat on private lands has been eliminated by logging, suitable habitat remains on federal- and state-owned lands. Areas of critical habitat have been designated within the three-state area to protect habitat and promote the recovery of the species. These areas include approximately 3 million acres of federal lands and almost one million acres of state, county, city and private lands. Over the next 50 to 100 years, the protected areas on federal lands should provide for an increase in suitable nesting habitat. Although timber continues to be harvested, timber sale programs on federal lands require consultation with the U.S. Fish and Wildlife Service to review and assess the potential impacts of the timber harvests on the marbled murrelet. In 1997, the Fish and Wildlife Service approved a recovery plan for the marbled murrelet that specified actions necessary to halt the decline of the species in the three-state area.

A five-year review was completed for this species in 2004.

References and Links

Regulatory Information

Listing Status: U.S. Fish and Wildlife Service. 1992. Final rule listing the marbled murrelet as threatened. Federal Register 57:45328-45337.

Critical Habitat: U.S. Fish and Wildlife Service. 1996. Final designation of critical habitat for the marbled murrelet. Federal Register 61:26256-26320.

Economic Analysis : U.S. Fish and Wildlife Service. 2007. Draft Economic Analysis of Critical Habitat Designation for the Marbled Murrelet. Report.; Federal Register 72:35025-35028.

Recovery Plan: U.S. Fish and Wildlife Service. 1997. Recovery Plan for the threatened marbled murrelet (Brachyramphus marmoratus) in Washington, Oregon and California. Portland, Oregon. 203 pp.

Federal Register Documents: Listing Status, Regulatory documents, current recovery plan, other recovery documents, Critical Habitat. View documents

Conservation Plans, Safe Harbor Agreements, Petitions: View reports

Northwest Interagency ESA Website: ESA and Streamlined Consultation documents, important references and links, and other materials Website

Status Reviews

Assessment through 1995: Ralph, C.J., G. L. Hunt, Jr., M. G. Raphael, and J. F. Piatt, (Technical Editors). 1995. Ecology and Conservation of the Marbled Murrelet. General Technical Report PSW-GTR-152, Pacific Southwest Research Station, U.S.D.A. Forest Service, Albany, CA

10-Year Report: Northwest Forest Plan—The first 10 years (1994-2003): status and trends of populations and nesting habitat for the marbled murrelet.Report

5-Year Status Review: U.S. Fish and Wildlife Service. 2004. Evaluation Report for the 5-Year Status Review of the Marbled Murrelet in Washington, Oregon, and California. Report

Alaska and British Columbia: Status Review of the Marbled Murrelet (Brachyramphus marmoratus) in Alaska and British Columbia. USGS 2006. Abstract; Download Report

Survey Protocols

Inland Survey Protocol: Methods for Surveying Marbled Murrelets in Forests: A Revised Protocol for Land Management and Research. January 2003. Report

Other Marbled Murrelet Websites

U.S. Geological Survey: Patuxent Bird Identification Center

Northwest Forest Plan Information

10-Year Report: Status and Trend of Late Successional and Old-Growth Forest. 1993-2003. Report

Regional Ecosystem Office: Northwest Forest Plan Website

USDA Forest Service, Pacific Region: Northwest Forest Plan Website