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Published: June 30, 2025
Pages: 29
Author(s): Jen Mannas
Executive Summary
The marbled murrelet (Brachyramphus marmoratus) is a small seabird that inhabits the nearshore marine environment in western North America. The species was listed as threatened under the U.S. Endangered Species Act in 1992 in Washington, Oregon and California, and subsequently listed by the Washington Fish and Wildlife Commission as threatened in 1993, primarily due to loss of old growth forest nesting habitat and mortality associated with net fisheries and oil spills. In 1997, Washington enacted State Forest Practices Rules to address impacts to murrelets from timber management on non-federal lands. Due to continued population decline of the species it was listed as endangered by the Washington Fish and Wildlife Commission in 2016.
Since 1993 nesting habitat losses due to timber harvest in Washington have been substantial and at-sea population monitoring from 2001 to 2024 indicated nearly a nearly 5.0% decline in the murrelet population annually. The 2023 population estimate for Washington was 4,400 birds (McIver et al. 2025), down from the estimated 7,500 in 2015.
Sustained low juvenile recruitment has been identified as a main cause of their decline, but research investigating the cumulative effects from threats on individuals and populations is ongoing. Vital demographic data are lacking, and nest success is influenced by both terrestrial and marine factors, such as the availability of nesting sites, amount of nesting habitat, nest predation, and prey availability and quality. Human marine activities appear to influence murrelet abundance and distribution in the Salish Sea. Declines in populations of forage fish species resulted in an increased consumption of lower trophic level food sources (invertebrates). Ultimately, changes to the marine food web may have influenced reproductive output. Federal and state landscape plans and Forest Practices Rules, implemented to help stem the loss of higher quality nesting habitat, have been beneficial but have not led to recovery goals being met.
The continued population decline indicates that marbled murrelets in Washington have become more imperiled since state listing in 1993. Without solutions that can effectively address these concerns in the short-term, it is likely the marbled murrelet could become functionally extirpated in Washington within the next several decades. Therefore, our recommendation is to maintain the marbled murrelet as an endangered species in Washington.
Suggested citation
Mannas, J. 2025. Periodic status review for the Marbled Murrelet. Washington Department of Fish and Wildlife, Olympia, Washington. 28 pp.