Meet the marten: Oregon State research provides updated look at rare, adorable carnivore

CORVALLIS, Ore. – Oregon State University researchers have painted a clearer picture of the coastal marten, a secretive, ferret-sized forest carnivore renowned for its cuteness but nearly driven to extinction by human activity in the 20^th century.

Scientists from OSU’s Institute for Natural Resources led a three-month project that used non-invasive survey tools – hair snares and remote cameras – to collect marten population and habitat data in a 150-square-mile area east of the northern California town of Klamath in 2022.

Genetic analysis of the hair identified 46 different martens, 28 males and 18 females. Martens were found throughout the study area and were most numerous at high elevations along forested ridgetops with consistent winter snowpack, and at lower elevations in ravines and riparian areas in coastal forests.

The findings are important for informing conservation and land management decisions that affect the coastal marten, a member of the weasel family also known as the Humboldt marten. The species is listed as threatened under the federal Endangered Species Act, and the small populations of martens that remain – in northern California and southern Oregon – are at risk from rodenticides, vehicles, disease and habitat loss.

“Coastal martens like forests with old-growth characteristics and those types of forests are being threatened by the effects of climate change, including more frequent and severe wildfire, and certain forest management practices,” said OSU wildlife ecologist Sean Matthews. “Beyond that, there’s a lot we don’t know about this species, including information as basic as what forests do coastal martens still occupy, how many martens are there, and are these populations increasing.”

Coastal martens, which Matthews describes as “among the most adorable animals that call our Pacific Northwest forests home,” once ranged from northern Oregon to northern California. Their population and range shrunk dramatically during the previous century as trapping – they were valued for their fur – and logging pushed them to the brink of vanishing.

In fact, they had been considered extinct before a small population was found in the coastal woods of northern California in 1996 by a U.S. Forest Service biologist.

The study led by OSU, which featured multiple partner organizations including Cal Poly Humboldt and the University of Wisconsin Madison, took place on ancestral lands of the Yurok and Karuk Tribes, at elevations ranging from 100 feet to 4,600 feet, on parcels currently managed by the U.S. Forest Service, the Yurok and the Green Diamond Resource Company.

The Yurok Tribe owns one-third of the study area, land that had been owned and managed for commercial timber production by Green Diamond until 2019. The Tribe manages the land for multiple uses, including plant and wildlife habitat restoration, conservation of cultural resources and some timber harvesting.

Green Diamond still owns and manages about one-fifth of the study area, and the Forest Service manages its portion of the area for habitat and watershed restoration, recreation, timber harvesting and cattle grazing.

The scientists gathered their marten data via 285 hair snares, fashioned from PVC pipe, and 135 cameras. 

“Martens tend to select forest stands with greater than 50% canopy cover and lots of large-diameter trees, snags and hollow logs,” said OSU faculty research assistant Erika Anderson, who led the study under Matthews’ direction. “Structural complexity with coarse woody debris helps them hunt and also provides cover from predators and competitors. But despite continued conservation concern over the last 30 years, we have a lot to learn about marten distribution and demography and how forest conditions influence their distribution and density.”

Also participating in the research were scientists from the California Department of Fish and Wildlife, the Yurok Tribe, Green Diamond, Six Rivers National Forest, the National Council for Air and Stream Improvement, and the National Genomics Center for Wildlife and Fish Conservation. Partner organizations funded the project with support from the U.S. Fish and Wildlife Service and the Volgenau Foundation.

Findings were published in Global Ecology and Conservation.