Oregon State University researchers used remote cameras and hair snares during a three-month 2022 survey to document coastal (Humboldt) martens across approximately 150 square miles east of Klamath, California. Genetic testing identified 46 individual martens (28 males, 18 females). The animals concentrate on snowy ridgetops and sheltered ravines and riparian forests. With an estimated ~500 individuals remaining in northern California (about 5% of historical numbers), martens face threats from wildfires, habitat loss, rodenticides, vehicles, and disease; the results will guide conservation for this federally threatened species.
Hidden Trail Cameras Reveal Coastal Martens Living in Northern California — Once Thought Extinct
A coastal marten on a trail cameraOregon State University
Hidden trail cameras and hair-snare stations have confirmed that coastal (Humboldt) martens — a species once believed to be locally extinct — are living across a roughly 150-square-mile area east of Klamath, California, researchers from Oregon State University report.
Study Design And Discovery
During a three-month survey in 2022, OSU scientists deployed remote cameras and hair snares to gather photographs and DNA evidence. Hair snares are simple devices that collect hair samples on tape or wire as animals pass, allowing genetic identification without capturing the animals. Genetic analysis of samples identified 46 distinct martens in the study area: 28 males and 18 females.
Although martens were widely thought to have disappeared from much of the region after heavy 20th-century trapping for fur, a U.S. Forest Service biologist first located a remnant population in 1996. The OSU study builds on that rediscovery by mapping where martens currently live and estimating local abundance.
Coastal martenOregon State University/YouTube
Where Martens Are Found
Researchers detected martens in multiple parts of the survey region. They were most abundant on forested ridgetops that retain consistent winter snowpack and in lower-elevation ravines and riparian corridors along the coast. These patterns suggest martens use a mix of high-elevation refuges and sheltered coastal forests.
Population Size And Conservation Concerns
Current estimates place roughly 500 coastal martens in the northern California coastal woods — about 5% of the species' historic numbers in that landscape before intensive fur trapping. Coastal martens prefer forests with old-growth characteristics, habitats that are increasingly threatened by climate change-driven factors such as more frequent and severe wildfires and by certain forest management practices.
“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 wildfires, 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.”
Other threats include rodenticide exposure, vehicle collisions, disease, and continued habitat loss. The coastal marten is currently listed as threatened under the U.S. Endangered Species Act.
Implications For Conservation
The study’s findings, published in January in the journal Global Ecology and Conservation, provide essential baseline data to guide conservation actions and land-management decisions aimed at protecting martens and their habitat. Continued monitoring and targeted habitat protection will be critical to help these small, elusive predators persist in a changing landscape.
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