About Martes caurina (Merriam, 1890)
The Pacific marten (Martes caurina, first described by Merriam in 1890) is a North American mammal that belongs to the Mustelidae family. It is distributed across western North America. The Pacific marten has a wide but fragmented distribution across western North America; this fragmented pattern is thought to result from how the species colonized new habitats as ice sheets retreated. Its range extends from the Alexander Archipelago and Haida Gwaii archipelagos, south along the Pacific Northwest coast to Humboldt County, California, and east to the southern Rocky Mountains, reaching as far south as New Mexico. A broad hybrid zone between Pacific martens and American martens has been identified in the Columbia Mountains, and also on Kupreanof and Kuiu Islands in Alaska. This species inhabits both deciduous and coniferous forests across the Pacific Northwest of the United States, the Rocky Mountains, and the Sierra Nevada. In Oregon, Pacific martens live on higher terrain because they can tolerate deeper snow. Their populations are divided into two separate habitat groups: one in the coastal mountains, where they can also be found at lower elevations, and one in the Cascade Range, where they mostly occupy mountainous pine forest areas. The two groups are separated by unsuitable lowland and valley habitat. In northeastern California, male and female Pacific martens have roughly equal home range sizes. In this region, movement patterns and home range boundaries are shaped by cover, topography (including forest-meadow edges, open ridgetops, and lakeshores), and interactions with other Pacific martens. In northwestern Montana, home range boundaries align with the edges of large open meadows and burned areas; researchers have suggested that open areas act as psychological rather than physical barriers for the species. Observations from Oregon indicate that juvenile Pacific martens may disperse during early spring. In a study of nine dispersing juvenile Pacific martens in spring in northeastern Oregon, three individuals dispersed an average of 33.3 km (range 28.0–43.1 km / 17.4–26.8 miles) and established new home ranges outside the study area. Three individuals were killed after dispersing distances between 8.5 and 23.5 km (5.3 to 14.6 miles). The remaining three dispersed an average of 8.0 km (range 6.0–9.7 km / 3.7–6.0 miles), then returned to establish home ranges near their original capture site. Spring dispersal ends between June and early August, after which individual martens stay in the same area to establish their permanent home range. Pacific martens are omnivorous, with rodents and rabbits being common prey. On Haida Gwaii, British Columbia, birds were the most important prey item when measured by both frequency of occurrence and volume in the diet. Fish may be an important food source in coastal areas. The diet of the Pacific marten is less diverse across its range than that of the American marten, though diet diversity exists across Pacific states.
