Fishers, members of the weasel family, have returned to the forests of Pennsylvania. Once extirpated from the state, these forest-dwelling carnivores have re-established a presence, adding to the diversity of wildlife in the Commonwealth. Their comeback is a testament to conservation efforts and the resilience of natural ecosystems.
Understanding the Fisher
The fisher (Pekania pennanti) is a medium-sized carnivore. These animals possess a long, slender body, short legs, and a bushy tail. While their overall fur appears dark brown, it often reveals a grizzled appearance on the back and shoulders with hints of gold and silver. Males are notably larger than females, with males typically weighing 7 to 15 pounds and reaching lengths of 35 to 48 inches, while females range from 4 to 9 pounds and 30 to 37 inches long.
Fishers are agile creatures, capable of climbing trees proficiently, though they spend most of their time foraging on the forest floor. They have wide, rounded ears and eyes that produce a green eyeshine at night. Despite their name, fishers rarely consume fish; the name may have originated from a word resembling “fichet,” a European polecat.
Fisher Presence and Habitats in Pennsylvania
Historically, fishers were widespread throughout Pennsylvania’s forests before the intensive deforestation of the 19th century led to their extirpation. However, the return of extensive forest cover through natural succession created suitable habitats for their re-establishment.
Pennsylvania’s current fisher population is a result of both natural expansion from neighboring states and deliberate reintroduction programs. West Virginia reintroduced fishers in 1969, and New York transferred them to the Catskills in 1979, with these populations contributing to natural dispersal into Pennsylvania. From 1994 to 1998, the Pennsylvania Game Commission, in partnership with universities and conservation groups, reintroduced 190 fishers from New Hampshire into six sites across northern Pennsylvania.
Today, fisher populations are well-established and expanding throughout the southwestern, central, and northern regions of the state. They are commonly found in forested areas, particularly large, contiguous blocks of mature hardwoods and conifers, which provide the dense overhead cover they prefer. These environments offer ample downed woody debris and structural diversity, supporting the prey base and denning sites fishers require. While once thought to need unbroken forests, fishers have demonstrated adaptability, expanding into some rural and suburban habitats in the Northeast.
Behavior and Diet of Fishers
Fishers are solitary predators, generally active during dawn and dusk, though they can be active at any time of day or night. They are opportunistic omnivores, with a diverse diet that includes small mammals, birds, fruits, and fungi.
A notable aspect of their diet is their ability to prey on porcupines. Fishers achieve this by repeatedly attacking the porcupine’s face, which lacks quills, until the porcupine is weakened. They then flip the porcupine onto its back to access its unprotected belly. This specialized hunting technique provides a significant food source. Beyond porcupines, their diet in Pennsylvania primarily consists of small mammals like squirrels, chipmunks, and mice. They will also opportunistically consume carrion, including deer, particularly during winter months.
Coexisting with Fishers
As fisher populations have recovered in Pennsylvania, the Pennsylvania Game Commission has implemented a scientifically based management plan to ensure their continued presence. This includes monitoring their distribution and abundance through various techniques, such as tracking sightings, roadkill data, and regulated trapping harvests. A limited trapping season for fishers has been in place since 2011, with specific regulations and harvest limits.
Direct encounters with fishers are uncommon due to their secretive nature. Concerns about aggression toward humans are largely unfounded, as fishers are generally not aggressive. To minimize potential conflicts, especially in areas where fishers are becoming more common, residents can secure pet food, garbage, and ensure outdoor pets like chickens and rabbits are housed in predator-proof enclosures. While they may prey on domestic cats, keeping cats indoors, particularly at night, can significantly reduce this risk. The return of the fisher represents a successful conservation story, highlighting the importance of healthy forest ecosystems.