Pacific fisher

Pekania pennanti

Description: The Pacific fisher (Pekania pennanti) is a member of the mustelid (weasel) family and is about the size of a large house cat. It has a long, slender body with short legs. The face, neck and shoulders are silver or light brown, contrasting with the tail, legs and rump, which are black. The Pacific fisher is a carnivore that lives in old-growth forests of the northern U.S. and Canada. West Coast fisher populations, living in the Sierra Nevadas and the Klamath-Siskiyou Mountains, are genetically distinct from other fisher populations.

Habitat: Fisher are tied to lower elevation, closed canopy forests, and require large trees for denning and resting. They are specialized and frequently travel along waterways and rest in or on live trees, snags, or logs with cavities found in large, undisturbed tracts of old forest. Douglas fir is the most common species used for resting in northern California, whereas oaks and true firs are commonly used in the southern Sierra. The diameter of trees used by fisher is consistently large. Rest sites are widely distributed throughout fisher habitat. Each individual travels over a home range of 50-150 square miles, even more in winter when food is scarce.

Endangered Species Act Listing status: Not protected.

Threats: Logging and development have caused severe loss and fragmentation of old-growth forests, and now as little as 15% remains in California, Oregon and Washington. Historically, fisher occurred in closed canopy forest types down the West Coast to the southern Sierra Nevada. Concurrent with trapping of fisher for fur was logging of fisher habitat, both for timber and to clear land for agriculture. Fisher have been harmed by widespread use of rat poisons (rodenticides) often used in the cultivation of cannabis. Fisher are still accidentally trapped and their low elevation habitat is the target of many current logging operations. Experts recommend significantly increasing protections for this species, due to these threats.

Estimated population: In recent years the Pacific fisher has disappeared from Washington and most of Oregon. Around the turn of the twentieth century, fisher numbers dropped drastically and their range experienced an extreme contraction. There are less than 5,000 fishers estimated in the greater Klamath-Siskiyou region. 

Superpower: Fisher prey mostly on small and medium-sized mammals, such as rabbits, porcupines, squirrels, and voles, and will also consume birds, carrion, and even fruit on occasion. Instead of chasing prey for long distances, the fisher uses the "sneak attack," often from a tree perch. The fisher is most active near sunset and sunrise. The fisher plays a key role in regulating the populations of its prey species, many of which can become destructive if left unchecked. Most notably, it is a specialized predator of porcupines, which it kills by flipping over to expose the non-quilled belly.

What’s being done? While fisher in the Sierra Nevada were listed under the ESA, the US Fish and Wildlife Service has yet to protect Klamath-Siskiyou fisher populations. Extinction of the Pacific fisher would be an irrevocable loss to the biological diversity of the temperate forests of the Klamath-Siskiyou. KS Wild will continue to advocate on behalf of these Klamath-Siskiyou denizens. You can see our complaint challenging the latest USFWS decision not to list the fisher here.

If you want to help protect the Pacific fisher, please consider donating to our Wildlife Defense Fund. 

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