The fortunes of fishers: on the wane in the West, the weasel's numbers are waxing in the East

Animals, Wntr-Spring, 2003 by Deborah Knight

The first two fishers Sally Beckwith raised for release to the wild were orphaned adolescents, and they took her to fisher school. They leapt horizontally between trees and stuck like Velcro balls. They chased each other headfirst down trees as if nothing were holding them, accelerating as they descended. When stressed or displeased, they emitted bloodcurdling screams.

Not long ago, Beckwith, a licensed wildlife rehabilitator who lives in Massachusetts, hadn't even known what a fisher was. The animals were eliminated from the state by the mid-1850s, and not until 1960 was another sighting recorded as they spread back southward from New Hampshire and Vermont. No one knows how many fishers now live in Massachusetts--they are rarely seen--but they do inhabit almost the entire state, even the suburbs of Boston.

Most Popular Articles in Reference: The importance of understanding organizational culture; Credit card attitudes and behaviors of college students; What factors attract foreign direct investment?; Libraries Need Relationship Marketing - mutual interest marketing concept, ...; How to set performance goals: employee reviews are more than annual critiques; More »

Since her experience with those first fishers in 1996, Beckwith has raised one or two each summer, all of them orphans that would have died without her care. Each fall, as they learn to hunt for themselves, they leave home, vanishing from her backyard into the hundreds of acres of woods that surround her house. Beckwith's first love is orphaned river otters--also members of the weasel family--but fishers have come to take second place. The year she raised a lone fisher, a female, Beckwith was able to spend more rime with the animal and came to understand fully the similarities between the two species. "Fishers have a reputation of being ferocious," she says, "but I realized she wasn't ferocious. Her personality was similar to an otter's, but she was running around trees instead of water."

Fishers are among the least understood of the weasel family, or mustelids, which also includes martens, minks, ermines, ferrets, badgers, otters, and wolverines. They are so elusive that even researchers who study them in the wild rarely catch a glimpse lone except in a trap. They are primarily nocturnal, live only in forests with a dense canopy, and often rest during the day high up in trees. The males and females encounter each other briefly in the spring to mate, but the fertilized egg does not implant in the uterus until 10 or 11 months later. Then, after a 30-day pregnancy, the female gives birth to one to four tiny, hairless kits in a tree cavity, often an enlarged woodpecker nest. She cares for them until they can hunt for themselves at around five months of age. Other than that, fishers live solitary lives.

Perhaps the greatest mystery of fishers, though, is this: in the eastern United States and the Midwest, they are doing well and have retaken, either naturally or through reintroductions, much of their former range. In the West. however, they are doing so poorly that three times in the past decade groups have petitioned to have them listed as endangered.

In the West, fishers once ranged from British Columbia south through Washington, Oregon, and California to the southern Sierra Nevada mountains. Now they live in just three isolated populations. One of these, in the southern Sierra, is believed to be at high risk of disappearing. At best a few hundred animals remain, separated from the northern California population by hundreds of miles. Because they are a remnant of the original western fishers, they are genetically invaluable.

With so little known about the southern Sierra fishers, Mark Jordan, a graduate student at the University of California at Berkeley, has been trying to obtain basic information about them. Each summer he sets out 44 widely dispersed traps, which he and his assistants check regularly. They bait each trap with a chicken wing wrapped in a sock and tied inside a wire cage that snaps shut when an animal tugs on the sock. An attached wooden box provides the trapped fisher a place to hide.

Most often Jordan catches nothing. Luck was running with him one day last August, and he caught three. As he approached a trap, he heard a chuckling sound, the sign of a nervous fisher. Jordan shone a flashlight in the box's hole, and a dark little face with green eyes peered back. Later Jordan returned with two assistants. They unrolled a blue mat on the forest floor and laid out an assortment of equipment, including a syringe with anesthesia, a ruler, calipers, a scale, a tape measure, a thermometer, and antibiotic ointment. They injected the fisher, and after she h ad closed her eyes, they weighed her: just under five Founds. A male would have been half again as big or more. They laid her on the mat.

She already had an ear tag, since she had been caught the year before. This was her home range, probably about 10 square miles, which would not overlap with another female's range. Two of her four nipples were enlarged, a sign she had raised kits this year. She had told scars on her legs, body', and neck. Her nails were frayed, her powerful canines worn dull, her teeth covered with tartar, her gums red. She was mangy, with large patches of fur missing. Life, it seems, can be hard for a mid-sized forest carnivore, especially a female who must feed her young as well as herself. By contrast, field notes on a non-lactating female also caught that day reported an animal that "looked great": nothing but a few burrs on her fur.

Featured Download

Speak Like a CEO

The fortunes of fishers: on the wane in the West, the weasel's numbers are waxing in the East

Animals, Wntr-Spring, 2003 by Deborah Knight

Find Research Guides for:

Find Featured Titles for: Business

Most Popular Articles in Reference

Most Popular Publications in Reference