# Distribution and Status of the Fisher (Martes pennanti) in Washington > How do you map a forest carnivore that almost nobody sees? Pulling together a century of sightings, trapping reports and museum specimens, researchers found that fishers were hanging on in Washington’s Cascades, Olympics and Okanogan Highlands, but were very rare. Deep snow, clearcuts and the importance of swamps and streamside forests all help explain where they were still found. Summary by Kersey Lawrence, Original Wisdom. Updated 9 November 2026. Page: https://www.originalwisdom.com/tracking-literature/1992-aubry-houston-distribution-status-fisher-martes/ ## Citation and access - **Authors:** Keith B. Aubry and Douglas B. Houston - **Year published:** 1992 - **Journal or source:** Northwestern Naturalist - **Full citation:** Aubry, K. B. and Houston, D. B. 1992. Distribution and status of the fisher (Martes pennanti) in Washington. Northwestern Naturalist 73(3): 69-79. - **DOI:** 10.2307/3536711 - **Access status:** Publisher link only - **Where to find it:** https://doi.org/10.2307/3536711 ## Tags - **Species:** Mammals > Fisher - **Region:** North America > United States - **Tracking:** Tracking; Tracks - **Behaviour and ecology:** Behaviour; Habitat selection - **Methods and technology:** Descriptive statistics; Distribution mapping; Geographic Information System (GIS); Observer reliability - **Data type:** Existing data - **Observer qualification:** Not reported - **Discipline:** Behaviour and ecology - **Year published:** 1992 ## Detailed keywords - **Species:** Studied: fisher (Martes pennanti). Mentioned for context only: northern spotted owl (Strix occidentalis caurina) and marbled murrelet (Brachyramphus marmoratus), both listed as threatened old-growth forest species. Forest trees naming the vegetation zones: Sitka spruce (Picea sitchensis), western hemlock (Tsuga heterophylla), Pacific silver fir (Abies amabilis), mountain hemlock, subalpine fir (Abies lasiocarpa), grand fir (Abies grandis), Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa). - **Location and habitat:** Washington State, United States. Olympic Mountains, Cascade Range (east and west of the crest), Okanogan Highlands; no records from the eastern edge of Puget Sound, the Kitsap Peninsula, the southern Coast Range or the Blue Mountains. Areas with repeated sightings: Sullivan Lake (Pend Oreille County), Bryan Butte east of Lake Chelan (Chelan and Okanogan counties), and the Quinault, Queets, Skokomish and Hamma Hamma river drainages (Olympic Mountains). Specimen sites: Lilliwaup Swamp area (Mason County) and a swamp near Orting (Pierce County). Vegetation zones of Franklin and Dyrness (1973): Sitka spruce, western hemlock, Pacific silver fir, mountain hemlock, subalpine fir, timberline/alpine, grand fir/Douglas-fir, ponderosa pine and steppe. Records at about 100 to 2200 m elevation. - **Topics:** species distribution and status; historical and recent records; rarity; reliability ranking of sighting, trapping and track reports; forest vegetation zones; elevation; snow depth limiting movement; swamps, forested wetlands and riparian zones; clearcut logging and forest fragmentation; old-growth forest; snags and natal dens (from other studies); age from tooth cementum layers; ruling out escaped captive animals; endangered species listing petition; management recommendations. - **Statistics or models:** Descriptive statistics only (counts and percentages by period, reliability rating, vegetation zone and 100 m elevation band). Records within 1.6 km of a vegetation zone boundary were left out of the habitat analysis. The acknowledgements thank a colleague for a GIS analysis. Inconsistency: the text gives the 1969 Lilliwaup (Mason County) specimen as UWBM #37530 and the 1990 Orting (Pierce County) specimen as UPSMNH #14784, but the Appendix lists UWBM 37530 as the 1990 Pierce County animal and UPSMNH 14784 as the 1969 Mason County animal. - **Data type:** Existing data: 137 records from 1894 to October 1991, gathered from state and federal agency files (Washington Department of Wildlife, three national parks, ranger districts in eight national forests), questionnaires to the State Trappers Association and state wildlife biologists, published accounts and museum collections. New examinations of two museum specimens (tooth sections, reproductive tract). Two more sightings (1949 and January 1992) received after the paper was written are given in a note. ## Synopsis ### 1. What they did Fishers once lived throughout Washington’s dense forests, but heavy timber harvesting over the past half century has changed much of that forest. A 1990 petition to list the fisher as endangered in the Pacific States was turned down because too little was known about where fishers lived and how they were doing. No one had yet mapped the fisher’s distribution across Washington or looked at which habitats they used. The authors set out to: - Find out where fishers were found in Washington from 1980 to 1991, and how that compared with 1955 to 1979. - Look at fisher records in relation to the major vegetation zones and elevations, separately east and west of the Cascade crest, because the forests on each side differ. They gathered sighting and trapping records from wildlife agencies, national parks and national forests, sent questionnaires to trappers and wildlife biologists, and added historical records from published accounts and museum collections. Most reports had never been checked in the field, so they ranked each one for reliability: (1) specimen or photo, (2) first-person trapping report, (3) detailed sighting by an experienced observer, (4) sighting by an observer of unknown or limited experience, (5) tracks, (6) too little or questionable detail. ### 2. What they found The records - 137 records from 1894 to 1991. The 22 records from 1894 to 1925 were too vague to map, but museum specimens from that time confirm fishers in both the Cascades and the Olympic Mountains. - No records at all from 1926 to 1954. - Of the 115 records from 1955 to 1991, only five were of captured animals: two museum specimens and three trapping reports. Of the rest, 17 were detailed sightings by experienced observers and 66 were sightings by other observers. - The 27 track reports and questionable records (ratings 5 and 6) were left out, leaving 88 records for analysis: 47 from 1980 to 1991 and 41 from 1955 to 1979. - The less reliable sightings (rating 4) showed the same broad pattern as the reliable ones (ratings 1 to 3), so all were combined. Two recent specimens - A female taken near Lilliwaup Swamp in 1969 was 2 years old, judged from layers in a tooth. An adult female fisher at least 4 years old had escaped from a game farm about 70 km to the north that spring, so this animal could not have been the escapee. - A female trapped in a swamp near Orting in December 1990 was 8 years old and not pregnant. Her body and teeth showed she had been living in the wild, not escaped from captivity. Where fishers were found - Fishers were still in the Cascade Range and Okanogan Highlands, and probably still in the Olympic Mountains, although the last one trapped there was in 1969. - There were no records from the eastern edge of Puget Sound, the Kitsap Peninsula, the southern Coast Range or the Blue Mountains. - In the northern Cascades, recent records came only from the east side. West of the crest, only 5 of 15 records were recent, and all 5 were in a national forest or national park above 750 m. The 10 older records came from a mix of lands, including six from private timberlands, at 100 to 1750 m. Habitat and elevation (65 records that could be placed in a vegetation zone) - West side (46): western hemlock zone 54%, Pacific silver fir zone 26%, Sitka spruce zone 20%. None from the mountain hemlock zone. - East side (19): subalpine fir zone 53%, grand fir/Douglas-fir zone 37%, timberline/alpine zone 10%. None from the ponderosa pine zone. - West side (55 records): 87% were below 1000 m and none above 1800 m. - East side (33 records): only 30% were below 1000 m, and 18% were at 1800 to 2200 m. - Several people reported fishers again and again over the years in a few places: near Sullivan Lake, east of Lake Chelan near Bryan Butte, and in four river drainages in the Olympic Mountains. ### 3. What they concluded - Fishers are apparently very rare in Washington. The scarcity of recent sightings, and especially of fishers caught by accident in traps set for other furbearers, strongly suggests numbers are precariously low. - The overall pattern changed little between the two periods, but the records only show that fishers were still present in areas they used before. This should not be read to mean the population is stable. - Widespread clearcut logging at lower elevations may have reduced or removed suitable habitat in the northwestern Cascades. - The lack of high-elevation records on the west side may be due to deep, soft snow (up to 7.5 m in the mountain hemlock zone), which restricts fisher movement. Less snow in the rain shadow east of the crest probably explains the many records there above 1400 m. - Both recent specimens came from swamps, and many sightings came from swamps or other forested riparian areas. Because riparian zones get some protection during logging, they may be critical habitat where upland forest has been heavily logged. - Places with repeated sightings over many years give strong evidence that fishers are present, and the authors recommend field studies there. - A survey based mainly on unchecked sightings is no substitute for intensive field work. Radio-telemetry studies will be essential to learn fishers’ habitat needs and population status in the Pacific Northwest. ### 4. How tracking was or was not used Track reports were collected along with sightings and trapping records, and ranked as reliability rating 5, below sightings by observers of unknown experience. All 12 track records, which date from 1955 to 1991, were then left out of the analysis together with the questionable records. The paper does not describe the tracks or who found them. In the discussion, the authors cite a California study in which fishers were detected on smoked aluminium tracking plates more often in older forest stands. ### 5. Tracker or observer certification Not reported. Sightings were ranked by whether the observer was “experienced” or of “undetermined or limited qualifications”, but the paper does not say how this was judged. Nothing is said about who reported the track records. ### 6. Other technologies, skills or innovations - A six-level reliability ranking for unchecked wildlife reports. - Age at death from tooth cementum layers, used to rule out an escaped captive animal. - Examination of a reproductive tract, body fat and tooth tartar to judge whether a specimen had lived in the wild. - Records plotted on a vegetation zone map, with records near zone boundaries left out. ### 7. Implications for conservation (from the paper) - Habitat for fishers in the region would likely be improved by: keeping forest fragmentation to a minimum, in old-growth and second-growth forest; keeping a high level of structure on the forest floor (fallen logs, leaning trees, low branches) in managed plantations; keeping large snags and live trees with dead tops, which provide den cavities; keeping continuous canopies in riparian zones; and protecting swamps and other forested wetlands. - Riparian zones may be critical habitat where upland forests have been heavily logged. - Field studies, including radio-telemetry, are needed to judge how threatened fishers are in the Pacific Northwest. ### 8. Implications for tracking (Original Wisdom's observations) _These are Original Wisdom's observations, not the authors'._ - Track reports were ranked below sightings by observers of unknown experience and then dropped. This shows how tracks and signs evidence was often treated when nothing was known about who read it; recording who found the tracks, and how their skill was checked, could let such records count. ## Cite this summary Lawrence, K. 2026. Summary of: Distribution and Status of the Fisher (Martes pennanti) in Washington (Aubry and Houston, 1992). Original Wisdom, Tracking Literature. https://www.originalwisdom.com/tracking-literature/1992-aubry-houston-distribution-status-fisher-martes/