Mustelidae Author Don E. Wilson Author Russell A. Mittermeier text 2009 2009-01-31 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 1 Carnivores 564 656 book chapter http://doi.org/10.5281/zenodo.5714044 df4b6a3c-ae64-4bcf-a990-77fc6599759c 978-84-96553-49-1 5714044 15. Fisher Martes pennanti French: Pekan / German: Fischermarder / Spanish: Marta pekan Taxonomy. Mustela pennant: Erxleben, 1777 , Eastern Canada . Recent molecular studies have suggested that the Fisher should be placed in its own genus, Pekania . Three subspecies are recognized. Subspecies and Distribution. M. p. pennanti Exxleben, 1777 — E Canada and NE USA. M. p. columbiana Goldman, 1935 — W Canada and and USA (Rocky Mts). M. p. pacifica Rhoads, 1898 — W Canada (coastal British Columbia ) and W USA . Descriptive notes. Head-body 55-65 cm (males), 45-556 cm (females); tail 30-50 cm (males), 30-40 cm (females); weight 3.5-5.5 kg (males), 2.2-5 kg (females), adult males are roughly twice the weight of females. The Fisher has a long body, short limbs, a bushy tail, and large feet with strong claws. It is the largest member of the genus Martes . The pelage is silvery-brown to black; the back of the neck and head are often grayish or silver. White markings on the throat and upper chest are common. The skull has a strong sagittal crest, which is particularly well- developed in older males. Dental formula: 13/3,C1/1,P4/4.M1/2=238, Habitat. Fishers are found in dense forests with a closed canopy; they avoid open areas. In north-eastern Canada and United States , they also occur in fragmented, mixed woodlots interspersed with agricultural land. In California , mid-seral Douglas-fir (Pseudotsuga menziesii) and white fir (Abies concolor) forest types compose the greatest proportion of Fisher home ranges in the Coastal Mountains; the greatest proportion of home ranges in the Sierra Nevadas are in the intermediate tree size class with dense canopy closure, and in mixed conifer forests. In south-central Maine , Fishers use a variety of forest types , especially during summer. During winter, they hunt intensively in dense patches of coniferous undergrowth (where Snowshoe Hare tracks are common) and use deciduous stands less than expected by availability. Food and Feeding. The diet includes lagomorphs (especially the Snowshoe Hare), North American Porcupines, ungulate carrion, small mammals, birds, reptiles, invertebrates, and fruit. During the winter in British Columbia , 18 types of mammalian and avian prey were found in 256 stomachs. The most commonly occurring prey species were Snowshoe Hares, Red Squirrels, and Southern Red-backed Voles. The diet varied between sexes: female fishers consumed small prey more frequently than did males. In the mountains of California’s Sierra Nevada , where the Snowshoe Hare and North American Porcupine are absent, other mammals are the most frequent food item; however, reptiles (20-4%) and insects (55-7%) are major components of the diet, and at least six fungal species are also eaten. In the mixed-conifer forests of the southern Sierra Nevada , where Fishers and American Martens occur together, the diets of both species are more diverse than reported elsewhere in North America. Although the diet of Fishers includes more birds,lizards, hypogeous fungi, and insects than that of American Martens, the dietary overlap is high. The great diversity of the diet in these two species may be due to the absence or rarity of large prey (such as Snowshoe Hares and North American Porcupines) or to a greater diversity of available prey types in the southern Sierra Nevada compared to other areas. In south-eastern Manitoba , Fishers prey heavily on Snowshoe Hares (84:3% frequency occurrence). In Vermont , most of the diet is mammalian (72%), with avian prey (15%) and fruit (10%) of secondary importance. In south-central Maine , winter foods include apples, porcupines, hares, Eastern Gray Squirrels (Sciurus carolinensis), Red Squirrels, Northern Flying Squirrels (Glaucomys sabrinus), mice (Peromyscus), voles (Clethrionomys gapperi and Microtus), and shrews (Sorex and Blarina). The fall and winter diet in West Virginia and Maryland includes ten mammal species, four bird species, one gastropod species, and two types of vegetation. White-tailed Deer (Odocoileus virginianus) is the most frequent dietary component. Medium-sized mammals such as Northern Raccoon and small mammals such as Peromyscus sp. are also major dietary components, although small mammals occur less frequently than reported elsewhere. Diet overlap between the sexes was found to be considerable and differences between the sexes in the occurrence of major food groups (small mammals, medium-sized mammals, large mammals, birds, and fruit) were not significant. Hunting strategies vary with prey type . Snowshoe Hares are caught after rapid zig-zagging chases. Fishers hunt porcupines by searching for their dens. The arboreal skills of Fishers enable them to chase porcupines down trees to the ground, where they kill them after lengthy attacks, during which the Fisher repeatedly bites the porcupine’s face (which is unprotected by quills). Activity patterns. Active during the day and night; most activity occurs shortly before sunrise and after sunset. Males and females show similar amounts of activity, and both sexes are active more frequently in summer than winter. Den/rest sites are in hollow logs or trees, brush piles, or in rock crevices. Fishers in California select restsites in forested areas that have dense canopies, large trees, and steep slopes. In the Coastal Mountains and Sierra Nevada in California , standing trees (live and dead) are the most common resting structures, with California black oak (Quercus kelloggit) and Douglas-fir the most frequent species in the Sierra and Coastal areas, respectively. Resting structures are within the largest diameter trees available, averaging 117- 3 cm for live conifers, 119- 8 cm for conifer snags, and 69 cm for hardwoods. Females use cavity structures more often than males, while males use platform structures significantly more than females. The diversity of types and sizes of rest structures used by males suggests that males are less selective than females. In the Sierra Nevada study area, where surface water is less common, Fishers prefer rest sites within 100 m of water. In a central hardwood forest, Fishers were found to rest in hardwood, softwood, and mixedwood forest types in proportion to their availability in the summer, but tended to avoid hardwood areas in winter. They used nests, cavities, and burrows in proportionto their availability in winter, but in the summer, Fishers preferred nests to cavities, and burrows were not used. Males tended to use larger cavity trees and mixed forest stands more often than females. During spring, summer, and fall in south-central Maine , Fishers prefer using rest sites in the branches of conifers, within coniferous stands. Movements, Home range and Social organization. Fishers are primarily terrestrial, but are also good tree climbers. They are capable of long movements in short time spans; individuals have been reported to move 90 km in three days, 45 km in two days, and 10-11 km in only a few hours. Usual daily movements are 1-5- 3 km . Movements of males are greatest during the spring breeding season; non-reproductive females move similar distances during all seasons. Adult Fishers are solitary outside of the breeding season. Mean home range sizes are up to 40 km * for males and up to 20 km * for females. There is little overlap between the ranges of individuals of the same sex, but there is extensive overlap between the ranges of opposite sexes. In the Coastal Mountains and Sierra Nevada in California , the mean home range size of males (39- 4 km ?) was significantly greater than that of females (9- 8 km ”); the home ranges of females were significantly greater in the Coastal area than in the Sierras. In eastern Ontario , the mean adult home range size was 4- 4 km ?, with up to 71% overlap of adjacent intrasexual home ranges. In Quebec , in an area where trapping had been prohibited for more than 20 years, mean home range size was 9- 2 km ” for adult males and 5- 4 km ?*for adult females. In south-central Maine , the home ranges of females were stable between seasons and years, but males moved extensively from February through April, and their ranges shifted between years. Home ranges averaged 30- 9 km ” for males (range = 10-6-78- 2 km ?) and 16- 3 km ? for females (range = 8-1-39- 1 km ?). The ranges of adults usually did not overlap with others of the same sex, except for males during spring. Fishers of both sexes shifted or enlarged their ranges to include areas left vacant when others of the same sex were removed. Population density in preferred habitat is one per 2:6-7- 5 km ? but in other areas it may be as low as one per 200 km *. The adult population density was calculated as 327/ 100 km * in eastern Ontario , 2.7/ 10 km ? in Quebec , and 1/2:8-10- 5 km ? (summer) and 1/8- 3-20 km * (winter) in south-central Maine . Breeding. Mating occurs from March to May. Implantation of the fertilized eggs into the uterus is delayed and births occur from January to early April. Litter size is up to six, but averages two to three. Natal and maternal dens are located high up in hollow trees. The young weigh less than 50 g and are born with their eyes and ears closed. The eyes open around seven weeks, weaning begins after two to three months, and separation occurs in the fifth month. Females reach adult weight after six months and males after one year. Status and Conservation. Classified as Least Concern in The IUCN Red List. Fishers are considered common throughout most of their range, particularly in Canada , but they may be threatened in the western USA . They are trapped for their fur. In the 19" and early 20™ centuries, excessive fur trapping and habitat destruction through logging led to a decline in Fisher populations over most ofits range. Closed hunting seasons, protective regulations, and reintroductions were then initiated in many areas. The Fisher has made a comeback in parts of the eastern United States , but it is still vulnerable in the western states, where it seems to be dependent on old-growth forests. Bibliography. Arthur & Krohn (1991), Arthur et al. (1989a, 1989b), Dzialak et al. (2005), Garant & Crete (1997), Kilpatrick & Rego (1994), Koen et al. (2007), Koepfli et al. (2008), Paragi et al. (1994), Powell (1979, 1981, 1993), Powell et al. (2003), Raine (1983, 1987), Van Why & Giuliano (2001), Weir & Corbould (2007), Wozencraft (2005), Zielinski, Duncan et al. (1999), Zielinski, Truex et al. (2004a, 2004Db).