New England Fishers Exposed to Rodenticides

Master’s student publishes foundational research in Environmental Monitoring and Assessment
An individual with long brown hair wearing a green jacket, blue jeans, and rubber gloves carries a container of supplies in one hand while walking beside a chain-link fence
In her role with Lincoln Park Zoo, Jackie Buckley, VG20, took tissue samples from rats in Chicago to survey for zoonotic disease. Photo: Abbott, Dan Socie

A study of fishers from New Hampshire and Vermont, led by Jackie Buckley, VG19 (MCM) (she/her), was published by Environmental Monitoring and Assessment in October 2023. The project, titled "High Prevalence of Anticoagulant Rodenticide Exposure in New England Fishers," revealed that nearly all the animals in the study were exposed to rodenticides.

Buckley conducted the research as a student in Cummings School of Veterinary Medicine's Master of Science in Conservation Medicine (MCM) program.

According to Dr. Chris Whittier, V97 (he/his), director of the MCM program and assistant teaching professor in the Department of Infectious Disease and Global Health, it was a first-of-its-kind study of New England fishers to be published. The project was inspired by a similar published study of fishers in California, where rodenticide exposure was associated with illegal marijuana cultivation.

Buckley collaborated with Whittier and Dr. David Needle, A03, V11, senior veterinary pathologist of the New Hampshire Veterinary Diagnostic Laboratory at the University of New Hampshire, among others, to conduct the study.

Working with Needle, Buckley gained permission to access liver samples from deceased fishers collected by the State of New Hampshire Fish and Game and the Vermont Fish & Wildlife Department in 2018 and 2019. The samples were sent to a diagnostic lab at the University of Pennsylvania for analysis.

Using liquid chromatography-mass spectrometry (LC-MS), an analytical technique that involves the physical separation of target compounds followed by their mass-based detection, all but one of the 45 animals sampled were positive for exposure to anticoagulant rodenticides (ARs), and 84% were positive for more than one type of AR. The most prevalent ARs detected were diphacinone (96%) and brodifacoum (80%).

Mostly consistent with the findings from the California fishers study, the results help to establish a baseline for exposure to ARs in New England fishers and suggest that ARs could threaten wild mesocarnivore species (medium-sized members of the taxonomic order Carnivora) in the region.

"Fishers are generally carnivores and primarily predators of squirrels, but they will eat other things, including mushrooms," says Whittier. "It's a mystery why so many are getting exposed to rodenticides, but I don't think fishers are nearly as deep woods wild as we'd like to believe."

Intrigued by the surprising results, Whittier is eager to learn how fishers ingest rodenticide. "We don't know how much rodenticide the fishers ate or how that affected them, but I have colleagues from Cornell University who are trapping and collaring fishers to monitor them in the wild," he explains. "Theoretically, it could be one of the ways to answer some of these questions."

Like most MCM students, Buckley submitted a draft of her manuscript as a capstone project of the 12-month intensive program. However, she was motivated by a drive to complete everything and an opportunity to become one of the first MCM students to publish their capstone paper. "Since published papers are a tangible accomplishment for universities, I wanted to complete it so future students may be able to get funding to do this, and it could be considered a measurable goal of the program," she explains. Buckley hopes more students will see it is possible based on her achievement.

From the Bronx Zoo to Cummings School of Veterinary Medicine
Growing up in New York City, Jackie was drawn to animals at a young age and regularly visited the Bronx Zoo with her father. "That's where it started for me," she says. After earning a B.S. in biomedical science at the University of New Hampshire, she worked as a zookeeper at Disney's Animal Kingdom. Her fluency in Spanish helped Buckley earn a trip to Colombia, her family's native land. The Disney Conservation funded a one-month trip, where she helped a conservation organization that works with communities and cotton-top tamarins.

"We collaborated with and learned from people of those communities on human behavior change," she explains. "It was a unified front to approach a local issue … a great example of working on a project from a One Health perspective."

Buckley was encouraged to explore master's programs and was excited to find the MCM program at Cummings School. "I had four years of work experience and felt that the MCM program aligned with my passions and to help grow the field of One Health."

She was learning about Geographic Information Systems, research skills, project management, communication, and much more prepared Buckley for the future. This led her to secure the One Health research coordinator position at the Lincoln Park Zoo in Chicago. "I wouldn't have this job if it weren't for the MCM program," she says.

Putting her research experience to use in Chicago
Buckley's experience conducting fisher research inspired her to explore the issue of anticoagulant rodenticides in urban animals in the Chicago area. "As urbanization expands, what does that mean for anything that we put into the environment?" she asks. "And how does that affect the animals that also call this area home?"

In her role at the Zoo, Buckley has obtained mammal carcasses from pest management companies to study the effects of rodenticides on mammals. 

Buckley partnered with The Field Museum in Chicago and local universities on this research, testing to learn as much as possible about anything from the diet and underlying diseases of the deceased animals to discovering exposure pathways of ARs. "Using what we learn, we work to provide residents with resources to help them keep wildlife out of their homes," she says. Buckley is writing a paper about her work on rodenticides in urban wildlife. 

She has also collaborated with RUSH University in Chicago and the Abbott Pandemic Defense Coalition to examine environmental samples and conduct testing to prevent the next pandemic. Buckley trapped and took tissue samples from rats in Chicago neighborhoods to survey for zoonotic disease. By learning of threats to animal populations, researchers can determine risks to the human population.

In addition to her role with the Zoo, Buckley is concurrently employed as a radiology manager at Northwestern University, where she manages three pre-clinical radiology labs.

Giving back to Cummings School's MCM program
Thankful for her Cummings School education, Buckley also created a one-time crowdsourcing fundraising effort to establish a scholarship fund to support MCM students in their externships. Funding a portion of her Fisher research motivated her to assist future students who may face a similar lack of funding.

"Equity is a big part of my values, so creating that scholarship fund was important to me. It later enabled a student to do an externship with the zoo, where they worked with our team, which was a great experience," she explains, hoping the fund will benefit future MCM students.

Buckley says, "I'm glad that the MCM program is getting more attention and that more students are doing research. It's hard to publish, but the motivation, support, and network that we have make it possible."

Whittier is thankful for Buckley's example as a compassionate and active alum. "Jackie is always finding opportunities for other students, such as her creation of the scholarship," he explains. "And she deserves much credit for getting her paper to the publishing stage. She joins other MCM graduates, helping to blaze a trail for others to follow her lead."

Working Toward Impacting the Environment

Cummings School’s M.S. in conservation medicine uses a One Health approach to educate and train students how to make an impact on the environment and ecosystem.