Marbled Murrelet Research at the CWE
Landscape, tree and branch photographs of 144 Marbled Murrelet nests from Desolation Sound (on the BC mainland coast), and around Clayoquot Sound (southeastern Vancouver Island)
The Centre for Wildlife Ecology has been investigating Marbled Murrelets, a threatened species in British Columbia, since 1995. Marbled murrelets are small, plump (~200g) fast flying seabirds belonging to the auk family or Alcidae. The year-round range of the Marbled Murrelet extends along the Pacific coast of North America from the Aleutian Islands of Alaska to central California. During the summer breeding season, ca. 30-5000 occupy in-shore waters off the British Columba coastline. While the bulk of the North American population is found in Alaska (approximately 75%), large numbers also breed along the coast of British Columbia (approximately 18%), where they are almost completely dependent on coastal old-growth forests for nest sites.
Unlike other seabirds in the auk family, which nest on cliffs, in burrows, or on predator-free off-shore islands, Marbled Murrelets nest solitarily in Old Growth forest trees with wide side branches, often many kilometres from water. Their solitary and secretive nature made their breeding biology difficult to study, and also created a clear population vulnerability to nesting habitat loss due to commercial forest harvesting. Although it is difficult to estimate population sizes or trends, there is concern that populations in BC have declined in areas where extensive logging of coastal forests has taken place. Perhaps their greatest current threat is from the ongoing felling of these forests. Additional and as yet unquantified threats include mortality through gill-netting and oil spills at sea.
To provide more accurate descriptions of Marbled Murrelet nesting habitat, SFU researchers located ca. 180 nests by radiotracking Marbled Murrelets tagged on the ocean back to their nest sites in Desolation Sound, on the BC mainland coast, and around Clayoquot Sound (southeastern Vancouver Island). These nests represent about half of all Marbled Murrelet nests ever found. Our ‘nest site gallery’ shows landscape, tree, and branch-level photographs of these sites. The information gained in this study contributed directly towards the recent designation of Critical Habitat for the species under Canada’s Species at Risk act (MAMU Recovery Strategy).
CWE hosted Marbled Murrelet documents
- Lank, D.B., N. Parker, E.A. Krebs and L. McFarlane Tranquilla. 2003. Geographic distribution, habitat selection, and population dynamics with respect to nesting habitat characteristics of Marbled Murrelets Brachyramphus marmoratus. Centre Wildlife Ecology, Simon Fraser University. Download report here
- Canadian Marbled Murrelet Recovery Team Conservation Assessment (2002, 2003): Part A - Review of the Biology, Populations, Habitat Associations and Conservation of Marbled Murrelets
- Canadian Marbled Murrelet Recovery Team Conservation Assessment (2002, 2003): Part B - Marbled Murrelet Recovery Team Advisory Document on Conservation and Management
- Canadian Marbled Murrelet Recovery Team Conservation Assessment (2002, 2003): Part C- Risk Analysis of Alternative Land Use Scenarios Technical report is available for download here and policy implication extension note is available here.
For more information on current work being done by CWE researchers with this species, contact David Lank.