Fisher

Description

The fisher is one of the largest members of the Mustelid or weasel family. The fisher (Martes pennanti) is the second largest member of the weasel family found in Massachusetts; only the river otter is larger. Although many people call them “fisher cats,” the name is inappropriate. They are neither members of the feline family, nor do they catch fish.

Except during their brief mating season, fishers are solitary creatures and are active during night and day throughout the year. (Source: MassAudubon)

Habitat
Behavior
Diseases
Resources
Habitat

Their preferred habitat is mixed forest with heavy canopy cover, as they tend to avoid traveling in large open areas. They commonly use hollow logs, stonewalls, tree cavities, and brush piles to rest.

Behavior

Fishers are shy and elusive animals that are rarely seen even in areas where they are abundant. They can be active day or night. They tend to exhibit nocturnal and crepuscular (dawn and dusk) activity in the summer and diurnal (daytime) activity in the winter. They remain active year round and do not hibernate.

Diet:  Fishers are omnivorous. Their primary foods include small rodents, squirrels, rabbits, birds, eggs, fruit, porcupines, and carrion. They will also opportunistically prey on poultry and domestic cats. Although they are proficient climbers, most of their hunting takes place on the ground. Fishers are one of the few mammals that prey on porcupines. Porcupines are difficult to kill, but a dead porcupine can provide many days of food for a fisher, so it is worth the effort. While on the ground, the fisher continually attacks the only vulnerable portions of the porcupine’s body, its face and underbelly. When facial wounds have weakened the porcupine, the fisher goes in for the kill. To avoid the quills, the fisher eats its prey starting at the head, neck, or underbelly.

 

Breeding & Reproduction:  Fishers breed from February to March and exhibit a reproductive strategy called “delayed implantation.” The adult female breeds within days after giving birth, but the fertilized eggs remain dormant in her uterus for the next 10 –11 months. The fertilized eggs then implant in the uterine wall and begin normal development. The young are born 1–2 months after implantation. Females produce 1 litter each year consisting of 1–4 kits, with an average litter size of 3. The young are born helpless, blind, and sparsely furred. Maternal dens, typically located in a cavity high in a large tree, are used for the first 8–10 weeks. Once the kits become mobile, they are moved from the maternal den to one on or below the ground. It is believed that the maternal den protects the helpless young from aggressive male fishers and ground predators. The female nurses the kits until they reach four months of age. By five months of age, the kits are approximately the same size as the adult female and have begun to learn how to kill their own prey. The young remain with the female until late summer or early fall, at which time they disperse to begin their solitary lives as adults. They reach sexual maturity at one year of age, and females produce their first litter at the age of two.(source: Mass.gov)

Diseases

canine distemper - contagious to unvaccinated domestic animals    (Source: Integral Ecology Research Center)

Journal of Wildlife Diseases, Jan. 2016

Resources

Hotline Info

DON’T LET FISHERS INTIMIDATE YOU: Don’t hesitate to scare or threaten fishers with loud noises, bright lights, or water sprayed from a hose.

Advice

Problems with fishers may sometimes arise, but are usually restricted to predatory attacks on domestic birds, rabbits, and free ranging house cats. If you want to make your property less attractive to fishers and avoid having any problems with these predators, follow these basic practices.

Keep bird feeder areas clean:  Use feeders designed to keep seed off the ground, as the seed attracts many small mammals, like squirrels, that fishers prey upon. Remove feeders if fishers are regularly seen around your yard.

Secure your garbage:  Exposed garbage, compost, and pet food can attract small mammals, which in turn attract fishers

Protect pets and poultry:  Fishers are predators that prey on medium-sized mammals and poultry. Fishers view domestic cats and rabbits as food, and will prey on them when hunting. They will also raid chicken coops and can kill numerous chickens at a time. For their safety, cats should be kept indoors at all times. Pet rabbits and poultry should be kept in tightly secured buildings or hutches that prevent access by fishers.

Actionable