The Marbled Murrelet is unique among members of the alcid family in its nesting habits. This small seabird nests in trees in coastal, older forests throughout most of its range in North America and Asia. First described by Gmelin in 1789 (as Colymbus marmoratus; Brachyramphus by Brandt in 1837), this species has been referred to more recently as the “enigma of the Pacific” because of its secretive behavior and elusive nests ( Guiguet 1956 ). After more than a century of unsuccessful attempts by early ornithologists to locate its nest, a $100 reward was offered for solving one of the last great ornithological mysteries in North America ( Arbib 1970a ). Finally, in 1961 and 1974, the first verified and published nests were reported in Asia and North America, respectively ( Kuzyakin 1963 , Arbib 1972a , Binford et al. 1975 ).
Referred to as the “Australian Bumble Bee” by fishermen ( Gabrielson and Lincoln 1959 ) and “fogbirds” or “fog larks” by Eskimos and loggers ( Bédard 1966 , Mccarthy 1993 ), Marbled Murrelets fly at high speeds, attend their breeding sites during periods of low light, and nest solitarily. These behaviors, combined with the challenges of capturing them at sea, have made this species difficult to study. Only in the last decade have some of its secrets been revealed; today more than 160 of its nests are known. Information remains limited, how-ever, on its nesting habits, behavior, habitat associations, and population numbers, and relatively little is known about its demography.
The distribution and numbers of this species have declined primarily because logging and coastal development have removed significant portions of its essential nesting habitat. Gill-net fishing and oil spills also kill this species and threaten its prey. The Marbled Murrelet was listed as a Threatened species in Canada in 1990 and in the southern portion of its range in the United States in 1992 ( U.S. Fish and Wildlife Service 1992d , M. Rodway unpubl. report).