What do fishers eat? There’s only one way to know for sure

Fisher facing forward
A fisher is a carnivorous mammal related to a weasel. Photo courtesy of John Van Niel

A professor and his students collect data on the stomach contents of this secretive mammal for the state Department of Environmental Conservation

A scalpel in her right hand, Chloe Bliss begins cutting into the brownish-pink organ she holds in her left.

This is part of her job as a work-study student at Finger Lakes Community College. Her boss is Professor John Van Niel, coordinator of the college’s fish and wildlife technology program. The work entails studying the stomach contents of fishers, a carnivorous north American mammal related to the weasel.

These solitary animals are fairly small, weighing up to 14 pounds, and have long bushy tails. Trapping for fishers is allowed in the fall in most of New York state, largely in the Adirondacks, Hudson Valley and North Country, with a brief season in the Southern Tier.

The state Department of Environmental Conservation (DEC) dropped off 500 frozen fisher stomachs at FLCC last year as part of an effort to gather data on New York’s fisher population. Fur trappers provided the carcasses so the DEC could study the teeth (to determine age), uteruses of females (to see how many kits they had) and the stomachs (to find out what they really eat).

John and his students can answer the last question: Fishers eat smaller mammals, as you might expect, but plenty of berries, fish, frogs, birds and, it seems, other fishers.

Female student using microscope
Jessica Froebel takes notes as she reviews the stomach contents of a fisher that had been caught by fur trappers. Photo by Rikki Van Camp

The students are earning a paycheck, learning research procedures and gathering data for further study or decisions about wildlife management. They understand their work will long outlast their time at FLCC.

“It’s like a good kind of pressure,” says Chloe’s co-worker, Jessica Froebel. “We’ve added to what the DEC can use and that’s important.”

Snake scales in a microscope
Snake scales
Snake scales in a microscope
Snake scales
Frog foot in a micrscopte
Frog foot

DEC biologist Scott Smith says the work of Bliss, Froebel and other students before them “saves DEC biologists and technicians untold hours and provides training for the next generation of wildlife professionals.

“Having this snapshot of fisher diet will allow the DEC to identify any potential difference in feeding strategies between historic fisher range and the more recently occupied habitats across central and western New York,” Scott explains. “Fisher were once considered a creature of the big woods, but in recent times have been found to excel in non-traditional habitats of mixed agriculture and even suburbia.”

The information has value to non-scientists, too. The students have not found evidence that fishers eat domesticated animals like chickens or pets.

“We often hear concerns from the public about the potential impact of fisher on other species like turkey and gray squirrel,” Scott adds. “It’s important to know for a fact what fisher are preying on. This study is showing that fisher rarely, if ever, consume wild turkey.”

Fishers are known for their strategy in attacking porcupines – they go for the face first to incapacitate – but the project results suggest they may not resort to this tactic very often.

Female students looking through microscopes
Chloe Bliss uses a microscope to identify the stomach contents of a fisher. Photo by Rikki Van Camp

The process starts with thawed organs, numbered in batches of 10, in an outbuilding at the FLCC Muller Field Station at the south end of Honeoye Lake. Jessica and Chloe open the stomachs, then remove and rinse the contents in strainers. They have gotten used to the smell, they said, except for the instances when a fisher has preyed on skunk. Next, they place the contents on numbered petri dishes and take a look under a microscope.

“I’m seeing a lot of fur here,” Chloe begins as she picks through the material. “There are two different animals in here, based on the feet I found, and there’s some red fur, possibly a squirrel…”

Looking at another small pinkish-red mass, she continues, “I can tell this is a head because I can see the jawbone here…”

Head and shoulders image of John Van Niel
Professor John Van Niel

The students identify the undigested materials using field guides and information they have learned from doing this over and over again. The contents of each stomach is matched to its number and will be uploaded into a database that also contains the sex, age and location and date of capture. Since trapping is permitted only in the fall, the results are limited to the animals’ fall diet. John checks their work, but even he gets stumped sometimes. “It’s humbling,” he adds, “I guess it’s a good thing I like learning because I’m still doing a lot of it.”

John, a Seneca Falls resident, is a 1983 graduate of FLCC and holds a doctorate in teaching and curriculum from the University of Rochester. He teaches Black Bear Management and Wildlife Management in addition to serving as director for both of FLCC’s field stations, the 48-acre Muller property in Canadice and the 85-acre East Hill Campus in Naples. He has been teaching at FLCC, based in Canandaigua, Ontario County, since 1995.

Chloe, 21, a Canandaigua Academy graduate, will get her FLCC degree in fish and wildlife technology in December. She has a two-year degree in animal management from Niagara County Community College and works part-time at Seneca Park Zoo in Rochester.

Jessica, 25, went to Alden High School in Erie County and will graduate with an associate degree in fish and wildlife technology next spring. She plans to use some of the fisher data for a mapping project in her geographic information systems class to see if diet varies by location. She was recently accepted into Cobleskill’s wildlife management bachelor’s degree program.

Four others took part in the fisher research in previous semesters. Jacob Ameele, a 2020 fish and wildlife technology graduate, and Allison Pellett, a 2020 environmental science graduate, were the primary student workers on the project. Courtney Renner, a 2020 environmental science graduate, and Gina DeBlieck, an environmental science major, also contributed to the research. FLCC’s conservation degree programs also include environmental conservation law enforcement and natural resources conservation.

Porcupine quill
Porcupine quill

Chloe and Jessica are enjoying the hands-on aspect of the project and the unpredictable nature of research. Unlike a lab exercise, there is no answer key.

“My grandfather used to say, ‘Every day you don’t learn something new is a day wasted,’ Jessica says, “This helps me learn something new. You never know what you are going to find.”



Author: Lenore Friend

Lenore Friend is the community affairs director at FLCC and the college's liaison with Finger Lakes TV. Contact her at (585) 785-1623 or Lenore.Friend@flcc.edu.

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