by Kristi Hobson Edmonston ·
Friday, May 1, 2026
By unanimous vote, Harvard’s Select Board banned the use of second-generation anticoagulant rodenticides (SGARs) on town-owned property, based on a recommendation made by the Conservation Commission. The vote occurred at its April 7 meeting. The Select Board had received a letter, signed by John Lee, vice chair of the commission, recommending the ban “for the sake of Harvard’s wildlife and the protection of [Harvard’s] local ecosystems.”
Lee’s letter also acknowledged the ban would “demonstrate the Town’s support for Mass Audubon’s campaign and its commitment to evidence-based environmental stewardship.” The campaign referred to is Mass Audubon’s Rescue Raptor campaign. This campaign involves a number of statewide and national partners, including Massachusetts Society for the Prevention of Cruelty to Animals (MSPCA-Angell), New England Wildlife Center, and the Massachusetts Veterinary Medical Association (MVMA). The campaign focuses on reducing or eliminating the use of SGARs in Massachusetts.
According to the U.S. Environmental Protection Agency, rodenticides are categorized as follows:
- First-generation anticoagulants, also known as multiple-dose rodenticides: warfarin, chlorophacinone, and diphacinone.
- Second-generation anticoagulants (SGARs), also known as single-dose rodenticides: brodifacoum, bromadiolone, difenacoum, and difethialone.
- Nonanticoagulants: bromethalin, cholecalciferol, strychnine, and zinc phosphide.
First- and second-generation anticoagulants both work by preventing blood clotting, causing fatal internal bleeding.
With first-generation anticoagulation rodenticides, the target animal must consume bait multiple times to receive a lethal dose. These rodenticides are less likely to cause secondary poisoning, as they break down in a target animal more quickly than SGARs.
SGARs pose a more significant risk to animals other than the intended target population. Animal populations can be impacted in two ways: Primary poisoning occurs if an animal, like a domesticated dog or cat, eats the bait and then dies due to internal bleeding. SGARs can deliver a fatal dose with a single feeding. Secondary poisoning takes place because SGARs bioaccumulate; that is, they build up over time in poisoned prey. So an animal that consumes the poisoned prey will also suffer severe, and often fatal, internal bleeding. SGARs are slow-acting, taking several days to kill a rodent, which means there is a greater likelihood a predator will consume the rodent before it dies. Because SGARs persist in body tissue for a longer time, scavengers who consume affected dead animals are also affected.
In 2021, the Massachusetts Department of Wildlife and Fisheries (MassWildlife) confirmed the first case of a bald eagle’s death due to SGARs. According to information provided by MassWildlife, secondary poisoning has been documented in eagles, hawks, owls, foxes, fishers, bobcats, and coyotes.
Although the discussion of the impact of rodenticides often centers on wildlife, pets are also affected. The Massachusetts Veterinary Medical Association is a professional association for veterinarians and veterinary students from a broad range of specialties, including large and small animals and wildlife. Jamie Falzone, executive director of the association, said, “It [the organization’s support of restricting rodenticide use] started with the wildlife impact, that’s what has been in the media the most. But it’s not just the wildlife.” According to the association, veterinary care to treat an animal who has ingested rat poison can exceed $2,000, and the animal needs weeks of supportive care and medication to recover.
The Select Board’s decision occurred shortly before the Massachusetts Senate approved the Mass Ready Act. This bill includes an amendment allowing any town to restrict or ban anticoagulant rodenticide use within their borders on public and private property. The Mass Ready Act passed the Senate on April 15 by a 36-3 roll call vote and was sent to the House of Representatives for further review.
When asked about the importance of the legislation, state Sen. Jamie Eldridge, who represents Harvard and nearby communities, said, “I am a proud sponsor of the bill to ban rodenticides statewide, and I was pleased that the Senate version of the Mass Ready Act included several policies, including a local option for municipalities to ban rodenticide. I have heard from many constituents on this effort. It is heartbreaking to read of so much wildlife, including the state’s treasured eagles, dying from ingesting this poison.”