Distribution and abundance of the fisher (Pekania pennanti) on the Makah Reservation and surrounding lands on the Makah Reservation and surrounding lands in northwestern Washington State lands in northwestern Washington State

McCaffery, Rebecca; Murphie, Shannon; Happe, Patricia; Jenkin, Kurt

Fishers were extirpated from Washington State in the middle-to-late 1900s and were listed as a State endangered species in 1998. To restore the species in Washington and enhance its status throughout the West Coast of the U. S., the Washington Department of Fish and Wildlife and the National Park Service translocated 90 fishers from British Columbia to Washington’s Olympic Peninsula from 2008 to 2010. Peninsula-wide camera-based monitoring conducted from 2013 to 2016 revealed that the reintroduced population had become established throughout much of the Peninsula. The goal of the project reported here was to enhance our understanding of the current status and distribution of fishers on the Makah Reservation and surrounding areas nearly a decade after their reintroduction, and to provide information to Makah biologists that will help inform future forest management planning. Our first objective was to determine habitat and landownership associations of fishers in the study area using occupancy models. Our second objective was to estimate the population size and density of fishers on and near Makah lands using capture-recapture methods based on genetic identifications of individual fishers. The 450 km2 study area included all Makah lands (trust land and fee status land), as well as lands in private ownership and in Olympic National Park. We sampled fisher occurrence at 58 sites, each of which included two stations, with 1 remote-camera and 1 hair-snaring device at each station. Each site was sampled for 6 consecutive weeks each year, with weekly visits to collect photographic images and hairs for DNA analyses. We detected fishers at 13 sites in 2017 and at 9 sites in 2018. We identified 7 individual fishers from DNA, of which 2 were male and 5 were female. The best supported model of detection probability indicated that the previous detection of a fisher increased detection probability in subsequent sampling sessions. Model selection results for occupancy based on the top detection model indicated that occupancy increased as distance to the late-seral protected forest (i.e., wilderness) boundary decreased. We found no evidence that the proportion of medium and large trees, dense canopy cover, tribal trust and fee lands (“tribal non-wilderness”), or late-seral protected forest (hereafter, “wilderness”) in the buffer had a strong influence on occupancy. Estimated occupancy in 2017 was 0.308 (0.187 – 0.461 95% CI), and in 2018 was 0.240 (0.124 – 0.412). Results from closed population models based on genetic capture-recapture data indicated that approximately 6-8 fishers inhabited the study area in 2017, but data collected in 2018 were inadequate to estimate abundance. Collectively, these results indicate that the mosaic of wilderness and actively managed forest lands has sustained a small population segment of fishers on Makah Tribal lands. Similar to the peninsula-wide study, we found that proximity to wilderness was the best predictor of fisher occupancy. This indicates that fishers, even at small spatial scales (i.e., much smaller than their home range), respond to features that occur in both wilderness and lands managed for timber production. We hypothesize that wilderness provides the requisite denning and resting sites that are key to fisher survival, whereas managed forest lands contain more abundant prey, especially snowshoe hares and mountain beavers. Our findings provide an important baseline for monitoring the status of fishers on the Makah Reservation in future years. Additional telemetry-based research would help to elucidate how fishers are using the mosaic of habitat conditions on Makah lands to meet their denning, resting, and foraging requirements.