The fisher (Pekania pennati) is a small carnivorous mammal, native to forests across the northeastern United States. Prior to European colonization of the area, the species was prominent throughout the region but declined because of over harvesting and loss of habitat (Graham and Graham 1994). To address this decline, many states, including New Hampshire, closed fisher harvest in the 1930s, which allowed populations to recover (Coulter 1960, Hapeman et al. 2011, Lewis et al. 2012). In 1969, New Hampshire reopened the harvest (Powell 1993), and today fisher trapping is permitted in December and hunting is permitted in December and January (NHFG 2023). Fishers are a crucial component of the forests in which they live, offer ecological services such as prey regulation (Coulter 1960), are valued for their pelts, and have intrinsic value in their existence as a species.
A fisher bounding along a downed log in Durham, NH in early January.
My research, funded by the Research Experience and Apprenticeship Program (REAP), was part of an ongoing project between the UNH Wildlife Monitoring and Management Lab (WMML) and the New Hampshire Fish and Game Department (NHFG) dedicated to evaluating fisher populations and mortality. It is important to evaluate fisher populations to help inform management practices and develop conservation policies. The main objectives of my research were to estimate population size using camera traps and existing photo data from the past three years; identify and quantify fishers’ relationships with their habitats; observe and identify causes of mortality; and use the above to make recommendations for best practices.
Methodology
My intended methodology was built on non-invasive, passive observations through established camera traps, image analysis and species identification, and a more hands-on approach of live trapping. Because the GPS collars that were necessary for the habitat relationship and mortality components did not arrive in time, my summer research focused on camera trap and image analysis.
The WMML has a statewide network of trail cameras established in 2022 to monitor various wild populations for research purposes at UNH. These cameras are checked twice yearly, once in late spring/early summer, and again in late summer/early fall. The cameras use motion detection to determine when an animal is within the range of the lens. I traveled to multiple field sites in the Seacoast area, Central NH, the Lakes Region, the White Mountains, and the Great North Woods. Initially, I worked alongside another undergraduate field technician with experience at these sites, but by the end of my REAP project, I was able to go out independently.
Navigating to many of the sites involved hiking and bushwacking, and carrying site-specific gear such as rope, stakes, flagging, SD cards, spare batteries, tripods, and extra trail cameras. In addition, I carried site maintenance tools such as loppers and a saw; as well as personal gear such as rain gear, extra layers, food, water, and a med kit. I used the app OnX Hunt, which allowed me to follow trails and track my path when off trail, all of which was especially important when out of cell service.
Once arriving at each site, I replaced the SD card in the camera (bringing the old card back to UNH with me for analysis), changed the batteries, and switched the image capture settings from “rest” to “summer” settings. Rest settings, used from approximately August to May, are so named because they will inform a Random Encounter and Staying Time (“REST”) statistical model that will estimate population density. These settings entail a low image-capture rate, or pictures taken per movement sensed, because species are less active during colder months. This also helps preserve battery life. Summer settings, used from May to August, have a higher image capture rate because species are more active, and the collection period is much shorter making battery life less of a concern.
A field site with the triangle set up for visibility tests on Mount Washington, NH.
At sites in the White Mountains and Great North Woods, cameras had to be lowered from their rest heights, which are higher to accommodate snowfall. At some sites, we needed to reevaluate camera visibility. To do this, I extended a transect tape 10 meters, centered on the camera. At 7.5 meters, I set up two stakes with flagging each approximately 2 meters away from the transect. Then, I laid down a yellow rope, beginning at 2.5 meters, forming a triangle with the two stakes. This was to assess the ground visibility at the center of the site. I also held up a 3x4 foot sheet of orange fabric vertically facing the camera at 10 meters away on the center of the transect, and to either side in line with the stakes. An image taken at each of the three positions assessed the site’s visibility above the ground in the main capture area. Images of the triangle and orange sheet were analyzed by other members of the lab back on campus using a software aid to determine percent visibility of each site.
After finishing these tasks, I completed a survey in ArcGIS to record any basic maintenance that I completed or that would be required upon the next visit to the site. I then hiked to another site within the same area or back to the car to drive to the next location.
Seeing double: a pair of moose passing by a camera in Errol, NH in late May.
These research activities, however, Dz’t paint the whole picture of the work associated with each site. The physical challenge required to access the cameras put us in terrain with every possible obstacle you can encounter in NH—thick and prickly brush, rivers and wetlands, downed logs, dense forests, steep and rocky terrain in the alpine zone, rain, intense wind, thunderstorms, mosquitoes and horseflies, and what seemed like a constant heat wave. Sometimes cameras were broken or waterlogged, which meant not only changing SD cards and batteries, but the entire camera. On one instance, I unknowingly dropped the keys for the lock boxes at a camera site and had to hike back thirty minutes to get them.
On days I ɲ’t in the field, I processed images on campus or at home using the software Timelapse2. This program helped us quickly identify species captured in images, tag the images, and compile the data in a spreadsheet. The software automatically sorts and compiles the quantitative data collected by the cameras, such as the camera ID, date, time, and temperature.
A bobcat with its back turned in Pawtuckaway State Park, NH in early April.
For identification, up to two different species could be marked in each image. Some species I observed included moose, bobcat, coyote, and white-tailed deer. I could mark any image for review, which allowed others in the lab to double check an identification.
At the time of writing, our lab has nearly fully processed images taken over the past year. Once I have access to the lab’s entire bank of images, as well as data from the postponed GPS study, I will begin drawing conclusions about fisher population trends and potential mortality causes. Initial data analyses confirm that fisher populations are generally low throughout the state and appear the most robust in the southeast. This pattern is surprising because the southeastern region of New Hampshire is more urbanized and developed, and traditionally fishers are not associated with developed areas.
Reflection: Takeaways and Future Plans
The job of a field technician is crucial for data collection in large scale projects, as it is incredibly labor intensive to travel to hundreds of field sites across the state. My REAPproject granted me tremendous experience in this line of work and research, and also benefitted the graduate students in our lab who will use this image data for their projects. In addition, this research will better inform NH state policymakers on best practices for fisher conservation and management.
The most important thing I learned about field work is the need for a positive attitude and the ability to be flexible. Sometimes, the circumstances ɴDz’t be right to do certain work on certain days, like crossing a swollen river after a rainstorm. I often had to make the best of a not-so-good situation and just go with the flow.
I am now employed by the Wildlife Monitoring and Management Lab at UNH and continued analyzing images throughout the fall. Beginning this winter, I will assist with the fisher live-trapping effort. After completing my REAP project, I feel affirmed that I am working in the right area of study and am excited to continue my work over the coming months.
I would like to thank my mentor, Professor Rem Moll, for taking me on and giving me the opportunity to gain such hands-on research experience in my first year at UNH. I would also like to thank Andrew Butler and Mairi Poisson for helping to coordinate all my work in the field. Thank you to Eleora McCay for showing me the ropes during my first few weeks, I would still be lost in the woods without you. And thank you to Mr. Dana Hamel and the Eric Wilkes Bell Memorial Award Fund for providing the funding that made my REAP grant possible.
References
Coulter, M. W. 1960. The status and distribution of fisher in Maine. Journal of Mammalogy 41:1–9.
Graham, R. W., and M. A. Graham. 1994. Late Quaternary distribution of Martes in North America. Pages 26–58 in S. W. Buskirk, A. S. Harestad, M. G. Raphael, and R. A. Powell, editors. Martens, sables, and fishers: Biology and conservation. Cornell University Press, Ithaca, NY, USA.
Hapeman, P., E. K. Latch, J. A. Fike, O. E. Rhodes, and C. W. Kilpatrick. 2011. Landscape genetics of fishers (Martes pennanti) in the Northeast: Dispersal barriers and historical influences. Journal of Heredity 102:251–259.
Lewis, J. C., R. A. Powell, and W. J. Zielinski. 2012. Carnivore translocations and conservation: Insights from population models and field data for fishers (Martes pennanti). PLoS ONE 7.
NHFG. 2023. New Hampshire & trapping hunting digest. New Hampshire Fish and Game Department, Concord, NH, USA.
Powell, R. A. 1993. The fisher: Life history, ecology, and behavior. University of Minnesota Press, Minneapolis, MN, USA.
Author and Mentor Bios
Tyler Olkkola, from Ossipee, New Hampshire will graduate in May 2027 with a bachelor of science degree in wildlife and conservation biology. He began his field research on fishers through a Research and Experience Apprenticeship Program (REAP) grant funded by the Hamel Center for Undergraduate Research. Although challenging, Tyler feels that his experiences made him a better researcher and more prepared for time in the backcountry; either conducting more research, leading trips for the New Hampshire Outing Club, or when he attends the EcoQuest Study Abroad program in New Zealand in the spring of 2026. Tyler wanted to publish his work in Inquiry to help educate the public on how much work goes into developing conservation and management plans. He emphasizes the increasing importance of such research as climate change and urbanization alter the habitats of species across New Hampshire and the world.
Remington Moll is an assistant professor in the Department of Natural Resources and the Environment. He started teaching at UNH in 2020 and specializes in wildlife ecology and management. Moll has mentored several students who received grants through the Hamel Center for Undergraduate Research; Tyler Olkkola is his second mentee to publish in IԱܾ.
Copyright © 2024, Tyler Olkkola
