Characteristics of Three Marbled Murrelet Tree Nests, Vancouver Island, British Columbia

Abstract

Three marbled murrelet tree nests were discovered in the Carmanah-Walbran region on the west coast of Vancouver Island, British Columbia in 1992. A11 nests were located by climbing trees in an area where murrelets were active and were unoccupied when found. The nests were in Sitka spruce (Picea sitchensis) and western hemlock (Tsuga heterophylla) trees on large (> 35 cm dbh), moss-covered limbs that appeared accessible by the birds only from below. The nest trees were the largest trees within a 25-m radius and all sites were located in valleybottom old-growth (> 200 yr) forest. A11 previously known murrelet nests in British Columbia had been found in Sitka spruce trees. Marbled murrelets (Brachyramphus marmoratus) are associated with the old-growth forest habitat along the Pacific coast of North America, where they nest on branch platforms in large conifers (Quinlan and Hughes 1990, Singer et al. 1991, 1995, Hamer and Nelson 1995a, Kerns and Miller 1995, Manley and Kelson 1995, Naslund et al. 1995). Marbled murrelets have also been found nesting on the ground and in cavities in southcentral and western Alaska (Simons 1980; Johnston and Carter 1985; Mendenhall 1992). In areas where murrelets nest in trees, their nesting habitat is threatened by logging and development. In the United States, the marbled murrelet is listed as a threatened species (U. S. Fish and Wildlife Service 1992) and although it is on the provincial blue-list of endangered species in Canada, only a small portion of murrelet nesting habitat is protected (Rodway 1990). In 1990 and 1991, forest surveys for marbled murrelets were initiated (Rodway et al. 1991, Manley et al. 1992) and the first 2 tree nests were located (Manley and Kelson 1995). These records were all associated with old-growth forest habitat. Limited information on marbled murrelet nest-site characteristics in Canada has seriously restricted the facilitation of meaningful management decisions for the conservation of this species (Rodway et al. Present address: Box 27062, Victoria, British Columbia, Canada V9B 5S4. 1992). This paper describes the characteristics of 3 additional murrelet nest sites found in the Carmanah and Walbran valleys of British Columbia in 1992.