Tracking the elusive Humboldt marten in coastal Oregon

marten with miniature radio collar

It’s the size of a 10-week-old kitten, constantly on the move, eats up to 25 percent of its body weight each day, and patrols up to 5 miles daily while hunting for songbirds and other food to fuel this active lifestyle.

The Humboldt marten (Martes caurina humboldtensis), is a subspecies of Pacific marten (M. caurina). It roams the Pacific Northwest’s coastal forests, usually so well hidden by the forest understory that it was believed to be extinct for more than fifty years.

In 1996, that changed when a small population of Pacific martens was discovered in California. The species is threatened by habitat loss as human development leads forests to become more fragmented, various diseases, trapping and vehicle-related mortality.

Yet, efforts to develop strategies for protecting the Pacific marten has struggled in the face of the tiny mustelids’ ability to stay to stay hidden, resulting in a lack of information about the existing population’s size, habits, and habitat needs.

Katie Moriarty, then a postdoctoral research wildlife biologist with the USDA Forest Service – Pacific Northwest Research Station, established a new baseline for monitoring and managing Humboldt marten populations in the Pacific Northwest. (Moriarty now works as a senior research scientist with the National Council for Air and Stream Improvement).

She worked with researchers and field crews representing more than half a dozen organizations and agencies to collect information about Pacific marten distributions Oregon and California, conducting what became the largest carnivore survey in Oregon.

Findings from that research confirm that small populations of Humboldt martens persist, but not only in late-sucessional forests as previously thought – but in fewer areas than researchers had hoped.

On Oregon’s central coast, scientists projected that just two to three deaths a year could lead to extinction of small, local populations of Humboldt martens within 30 years.

Find out more about this research in Science Findings #215
(a publication of the USDA Forest Service Pacific Northwest Research Station): https://www.fs.fed.us/pnw/sciencef/scifi215.pdf.

A marten captured by remote camera along the central coast of Oregon.
A marten captured by remote camera along the central coast of Oregon. With about 30 members in an isolated subpopulation, each marten counts when it comes to keeping the subpopulation from extinction. Courtesy photo by Mark A. Linnell, all rights reserved.

Source information: USDA Forest Service – Pacific Northwest Research Station

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