The Pacific fisher (Martes pennanti), an ecologically important forest carnivore, lives in low elevation old-growth forests of the northern United States and Canada. Recent genetic work established that West Coast populations, living in the Sierra Nevadas of California and the Klamath Mountains of northern California and southern Oregon, are genetically distinct, verifying the notion of a "Pacific" subspecies. The extinction of the Pacific fisher would be an irrevocable loss to the outstanding biological diversity of the temperate forests of the West Coast.
The fisher is a member of the mustelid (weasel) family, about the size of a 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. 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 for resting and denning 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. The latter of these activities has led to the current isolation of fisher populations.
Severe loss and fragmentation of habitat caused by logging, trapping and road building has led to the near extirpation of the fisher from its West Coast range. The recent large scale fragmentation of older forests on the West Coast and the combination of threats to this species have led to its precarious status. Fisher are still accidentally trapped and their low elevation habitat is the target of many current logging operations. Fisher experts recommend significantly increasing protections for this species, due to these threats.
The Pacific fisher desperately needs the protections of the 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. On November 28, 2000, 19 conservation groups 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 Endangered Species Act violations, the USFWS released a "warranted but precluded" finding on our petition. This acknowledges that while the species warrants protection, they have no money to do anything about it.