Pacific Fisher is One Cool Critter
The Pacific fisher (Pekania pennanti), a forest carnivore, lives in old-growth forests of the northern U.S. and Canada. Recent genetic work established that West Coast fisher populations, living in the Sierra Nevadas and the Klamath-Siskiyou Mountains of northern California and southern Oregon, are genetically distinct, verifying a "Pacific" subspecies. Extinction of the Pacific fisher would be an irrevocable loss to the biological diversity of the temperate forests of the West Coast.
Description and Ecology:
The fisher 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. 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.
Fisher are tied to lower elevation, closed canopy forests, and require large trees for denning and resting. They are specialized animals that frequently travel along waterways and rest in or on live trees, snags, or logs with cavities. These characteristics are usually only 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.
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.
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. Concurrent with trapping of fisher for fur was logging of fisher habitat, both for timber and to clear land for agriculture.
In addition to the severe loss and fragmentation of habitat caused by logging, development, trapping and road building, 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.
The Pacific fisher desperately needs the protections of the Federal Endangered Species Act. Immediate protection of this species is warranted by the small size and isolation of the remaining populations. Continued habitat loss from logging and development places the Pacific fisher in serious danger of extinction. In 2000, 19 conservation groups including KS Wild petitioned the U.S. Fish and Wildlife Service to list the fisher as endangered in California, Oregon and Washington.
After KS Wild and allies filed suit against the U.S. Fish and Wildlife Service (USFWS) in 2003 for failing to list the species. Eventually, the USFWS released a "warranted but precluded" finding on our petition. It has become clear over the years that failing to list the species is a political rather than scientific decision. Most recently in September 2018, a U.S. District Court ruled that KS Wild and allies were correct that the most recent decision not list the fisher was illegal. The Service is now ordered by the courts to revisit the listing status.