Local Species Information - Fisher (Martes pennanti)
Events and Items of Interest
A resident of coniferous and mixed coniferous forests, the fisher once occurred throughout much of Canada, the northern United States, and the western United States. Fisher populations have declined primarily due to loss of habitat from timber harvest activities and trapping. Populations of fishers have declined in all Canadian provinces and states except the Yukon and in the extreme northeastern United States (Maine, New Hampshire, and Vermont). In the western United States and Canadian Provinces, the number of fishers has been greatly reduced and their populations fragmented. Fishers are no longer believed to occupy the lower mainland of British Columbia and the area west of Okanogan extending down to Washington.
Adult fisher with radio collar. Photo Credit: J. Mark Higley,
Markings: The fisher is light brown to dark blackish-brown, with the face, neck, and shoulders sometimes being slightly gray. The chest and underside often has irregular white patches. The fisher has a long body with short legs and a long bushy tail. At 6.6 to 13.2 pounds, male fishers weigh about twice as much as females (3.3 to 5.5 pounds). Males range in length from 35 to 47 inches while females range from 29 to 37 inches in length. Fishers from the Pacific States may weigh less than fishers in the eastern United States.
American martens (Martes americana) have similar body shapes to fisher, but are smaller and usually lighter in color than fishers. The fur on the throat of martens is a buff or orange color; legs and tails are typically darker than the rest of the body. Female martens range from 18 to 22 inches in length and weigh 1.5 to 1.8 pounds. Male martens range from 20 to 25 inches in length and weigh 1.6 to 2.8 pounds.
American marten. Photo Credit: Eugene Wier
The American mink (Mustela vison) also has a similar body shape to fisher, but are smaller and usually darker in color than fishers. Their fur is deep, rich brown, with or without white spots on the stomach. American mink have webbing at the base of their toes, and their ears barely stick out above their fur. Females range from 18 to 22 inches in length and weigh 1.2 to 1.7 pounds. Males are slightly larger than females, ranging from 19 to 28 inches in length and 1.9 to 2.8 pounds.
American mink. © 2004 Ron E. VanNimwegen
The West Coast Distinct Population Segment includes the states of Washington, Oregon, and California. Fishers are known to occur in Oregon and California; fishers were re-introduced into the Olympic Peninsula of Washington in January and March of 2008. For more information on the re-introduction, please follow these links to Olympic National Park and Washington Department of Fish and Wildlife web pages. Fishers were translocated into the northern Sierra Nevada beginning in 2009. For more information on this effort please visit the California Dept. of Fish & Game's Fisher Translocation web page.
Map showing the current and historic range of fisher in the western United States.
Fishers use late-successional habitats with dense canopy closure, large diameter trees (conifers and hardwoods) and snags with cavities and other deformities, large diameter down wood, multiple canopy layers. Late-successional coniferous or mixed forests that contain key habitat and structural components provide the most suitable fisher habitat because they provide abundant potential den sites and preferred prey species. The physical structure of the forest and prey associated with forest structures are thought to be the critical features that explain fisher habitat use, rather than specific forest types. The West Coast population of the fisher inhabits forested areas from sea level along the California Oregon Coast to approximately 1,970 to 8,530 ft in the Sierra Nevada.
Fishers have a diverse diet that includes birds, squirrels, mice, shrews, voles, reptiles, insects, plants, fruit, and dead animals. Small and mid-sized mammals are the most common prey items eaten by fishers in the Pacific States. Fishers search for prey in forested stands, avoiding openings.
Except during the breeding season, fishers are solitary animals. The breeding season for the fisher is generally from late February to the end of April. Female fishers raise 1 to 3 kits, which are weaned by 10 weeks old. When they are 1 year of age, kits have established their own home ranges and are no longer dependent upon adults.
Fisher kits. Photo Credit: Cathy Raley,
USDA Forest Service, PNW Research Station
A list of literature pertaining to fisher, habitats, and prey is here
Habitat Conservation Plan
There are no Habitat Conservation Plans for the fisher.
For more information on Habitat Conservation Plans, click here
Safe Harbor Agreement
There are no Safe Harbor Agreements for the fisher.
For more information on Safe Harbor Agreements, click here
Candidate Conservation Agreements
There are no Candidate Conservation Agreements for the fisher.
For more information on Candidate Conservation Agreements, click here
Candidate Conservation Agreements with Assurances
The Yreka Fish and Wildlife Office has prepared a Candidate Conservation Agreement with Assurances (CCAA) with Sierra Pacific Industries (SPI). The CCAA includes approximately 160,000 acres of private, industrial timberland in Butte, Plumas, and Tehama Counties, California. The CCAA is for a time period of 20 years.
For more information on Candidate Conservation Agreements with Assurances, click here.
Links for More Information