Martes caurina

Dawson and Cook (2012) concluded that the pattern of molecular and morphological variation in North American martens supports the recognition of M. americana and M. caurina as distinct species with independent evolutionary histories. Regarding subspecies, they concluded that most of the nominal taxa in eastern North America are not supported by existing data (but see McGowan et al. 1999), whereas the subspecific classification in the west (i.e., within M. caurina) "more accurately reflects patterns of underlying geographic variation resulting from isolation in disjunct forest refugia during the last glaciation (Slauson et al. 2009)."

Large range in western North America, timber harvest and excessive harvest have led to extirpations and population reductions in some areas.

Range includes much of the contiguous western United States and part of southwestern Canada, including portions of California, Nevada, Oregon, Washington, Utah, Colorado, New Mexico, Idaho, Montana, South Dakota, Alaska (Kuiu Island, Admiralty Island), and British Columbia (Dawson and Cook 2012). Alaska, British Columbia, Idaho, and Montana have both Martes americana and M. caurina.

Zielinski et al. (2001) described the distribution of martens in coastal California, Oregon, and Washington from 1900 to 1949 using museum and trapping records and compared it to recent (1989-1998) detections at camera and track-plate stations. Martens were detected at only 12 of 237 (5.1%) survey sample units. Martens are absent from most of the historical range of the subspecies humboldtensis in California and also may have declined on the Olympic Peninsula of Washington. Few data exist from northwestern Oregon and southwestern Washington, but the limited amount of protected public land and absence of reported road kills are reasons for concern for populations in this region. Martens still occur in the central and southern coastal mountains of Oregon.

Past extensive logging and trapping for pelts led to extirpation in some areas. Martens are susceptible to overharvest when food supplies are low (Thompson and Colgan 1987). Loss/degradation of habitat due to timber harvest remains a threat in some areas.