Marbled Murrelet
(Revised October 2005)
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Photo from the cover of Ecology and Conservation of the Marbled Murrelet published by the USDA
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The Marbled Murrelet (Brachyramphus marmoratus) (MAMU) is a small Pacific seabird found in coastal nearshore waters of western North America ranging from the Aleutian islands in the north to northern Mexico in the south. This species is unique among members of the Alcidae in that it typically nests in trees associated with late-seral and old growth coniferous forests and may travel substantial distances inland to nest sites. Since murrelets do not construct their nests, they must rely upon the presence of old and/or mature trees with large limb diameters, deformities, canopy epiphytes, mistletoe brooms, or debris accumulations for suitable nesting platforms.
Declines in murrelet population numbers throughout their geographic range have been attributed to the species' low fecundity, increased at sea mortalities from oils spills and gill nets, and the increasing removal of suitable nesting habitat. In 1992, these factors prompted the U.S. Fish and Wildlife Service (USFWS) and the State of California to list the Marbled Murrelet as threatened and endangered, respectively.
Mendocino Redwood Company (MRC) works in conjunction with the California Department of Fish and Game (CDFG) and the United States Fish and Wildlife Service (USFWS) to protect murrelets and their habitat on the ownership. In order to determine if murrelets exist within or near timber harvest plans (THPs), surveys are typically conducted for two years in areas containing potentially suitable nesting habitat within 0.25 miles of a THP. MRC works closely with biologists from CDFG and the USFWS to assess potential nesting habitat and to determine an appropriate survey methodology. Despite the opportunity, MRC chooses not to harvest potential murrelet habitat even when no murrelets are detected. In fact, both MRC's old growth and wildlife tree retention policies cover a wide range of rare and unique habitats important to wildlife species, including the marbled murrelet.
In Mendocino and Sonoma counties, murrelet densities are low relative to populations further north in Humboldt and Del Norte counties. Because murrelets are often elusive and secretive birds, they can be very difficult to detect during ground surveys, especially at inland sites having low murrelet densities. In 1999, MRC began using marine radar to examine whether small numbers of silent murrelets were traveling up watersheds to inland nest sites. Although many of these areas contain small isolated patches of potential murrelet habitat, past ground surveys have yielded few or no murrelet detections.
On MRC's forestlands, murrelet surveys have been conducted annually in selected watersheds since 1994 to ascertain murrelet presence in areas of potential habitat and to monitor a known population in lower Alder Creek that was discovered in 1993. Annual surveys in lower Alder Creek since then have routinely detected murrelets, and in a few instances, behaviors indicating murrelets are occupying a stand (e.g., circling and/or subcanopy flights). Currently MRC is not harvesting timber in lower Alder Creek and is developing a lower Alder Creek Conservation Plan in conjunction with developing a long term sustainable forest management plan that includes the marbled murrelet as a covered species.
Currently, MRC has focused survey efforts for murrelets on habitats that have the highest potential for murrelet use. Watershed-level radar and ground surveys have been conducted in lower Alder Creek, Navarro, Albion, Elk, and Greenwood watersheds, with a majority of murrelet-type targets detected in Alder Creek. Since 2002, radar has been used annually at three locations along Alder Creek to monitor the murrelet population here and to determine their eastern extent within the watershed. In 2002 and 2003, for the first time ever, MRC biologists observed murrelets landing and taking off from the same tree in lower Alder Creek. Because MRC is committed to protecting unique habitats utilized by the marbled murrelet, the company will continue to conduct murrelet surveys in and around potential habitat and monitor the population in lower Alder Creek.
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For more information, go to the Pacific Southwest Research Station/Redwood Sciences Laboratory website to download chapters of Ecology and Conservation of the Marbled Murrelet published by the USDA.
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