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Is Brookline’s fight against rats putting other wildlife at risk?

A red-tailed hawk seen in North Brookline. Photo by Ashley D'Souza.
June 18, 2024

As the town and residents try to combat Brookline’s continued rodent problem — which includes a recent instance of rats coming up through a woman’s toilet — some advocates are pushing for alternatives to rat poison that minimize harm to other wildlife.

Second-generation anticoagulant rodenticides (SGARs) are a common treatment for rat infestations and can be found in bait stations near dumpsters and along the perimeters of buildings around Brookline. They can pose a serious threat to rodent-eating wildlife like bald eagles, hawks, owls and coyotes.

SGARs work by inhibiting vitamin K production in the body, preventing blood from clotting and causing internal bleeding, organ failure and paralysis. It can take several days for a poisoned rodent to die, giving it time to consume more poison and be eaten by a predator, who then suffers from secondary poisoning.

Brookline adopted an internal policy in May 2023 prohibiting the use of SGARs on town property, citing dangers to non-target predators and pets, negative impacts on soil and water quality and a counterproductive effect on rodent control efforts due to killing rodents’ natural predators. However, Massachusetts law prohibits towns from regulating pesticide use on private properties, where pest control companies still use bait stations containing SGARs.

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Advocates worry that poison threatens wildlife like bald eagles. A bald eagle named MK, one of the first bald eagles to nest in nearby Arlington in over 50 years, died from “catastrophic” internal bleeding due to SGAR poisoning in February 2023.

“I saw a bald eagle in Brookline Village last year and wondered if that magnificent bird was at risk from rat poison,” said Sean Lynn-Jones, president of the Brookline GreenSpace Alliance. “The Brookline GreenSpace Alliance fully supports the efforts of the Massachusetts Audubon Society to end use of SGARs and to protect raptors. We are trying to spread the word.”

A national study of dead bald eagles in 2021 found that 82% had been exposed to rodenticides, and a Tufts University study in 2020 found that 100% of red-tailed hawks at the university’s wildlife clinic were exposed to SGARs, up from 97% in 2017.

A bait box containing the rodenticide brodifacoum outside the Florida Ruffin Ridley School. Photo by Ashley D’Souza

Pets at risk, too

SGARs can harm pets as well. In March, a 6-year-old Golden labrador retriever and 7-month-old puppy belonging to a family in Reading died after ingesting rat poison.

“Each spring and summer, we get a few cases of rat poisoning in pets,” said Dr. Lori Feldman, veterinarian and co-medical director at the VCA Brookline Animal Hospital. “Our biggest concern is unlabeled poison usage, where pet owners are not made aware that SGARs have been applied.”

Environmental organizations including Mass Audubon, the Massachusetts Sierra Club, the Charles River Watershed Association and the Brookline GreenSpace Alliance are advocating to eliminate SGAR usage due to the risk of secondary poisoning.

Joslin Murphy, former town counsel, current Town Meeting member and a longtime environmental advocate, pushed for the town’s 2023 policy after learning that SGARs were being used on school properties.

Murphy is sympathetic to residents impacted by rodents, but she is confident that more humane and holistic rat control practices will prove to be a better long-term solution than SGARs.

“Folks who are deeply affected by the rodent population in Brookline are understandably upset,” she said. “But rats are really good at repopulating; you can poison them and electrocute them but that won’t make them go away.”

While the town’s policy includes a waiver for significant rodent infestations that have exhausted all viable less-toxic approaches, no waivers have been issued yet, according to Sigalle Reiss, Brookline’s Director of Public Health and Human Services.

The SGARs inside bait stations on town property have been replaced with snap traps, Reiss noted.

SGARs at home

Another Brookline resident, Sue Chin, encountered dead wildlife and noticed her neighbors around Brookline High School using loose rodent poison last year. She still hears other residents discussing using rat poison despite its risks.

“I found a lot of dead wildlife near my house, and one person told me she saw someone sprinkling white stuff from a bag into the bushes before taking off,” she said. “I’m hoping someone from the town enforces prohibiting people from using rat poison and holds them accountable if they do.”

SGARs are prohibited for residential consumer purchase both in Massachusetts and federally due to the dangers posed to children, pets and wildlife. However, licensed pest control companies still widely use SGARs — including many companies that serve Brookline, according to the state’s 2022 annual pesticide use report.

Poisonous baits containing brodifacoum, bromadiolone, difenacoum or difethialone are classified as SGARs. And while pest control companies are typically required to label any box containing SGARs with its ingredients, advocates claim they don’t always do so.

A barred owl at Halls Pond Sanctuary. Photo by Ashley D’Souza

Advocates push for a different approach

What will make rats go away, Murphy argues, is integrated pest management (IPM), which can reduce the rodent population in Brookline through comprehensive measures like proper trash control, sealed buildings and cleared brush.

The town recently updated its waste regulations with stricter rules for keeping dumpsters pest-free, and Reiss agreed that IPM is most effective.

“Any pest control that only uses rodenticides is not an effective strategy,” she said. “For mice or rats on commercial or private property, you always want to use integrated pest management strategies, looking at the whole environment to make sure it isn’t conducive to harboring rodents.”

One alternative to SGARs, ContraPest, can already be seen on some private properties in Brookline. ContraPest is a non-toxic rat contraceptive used by some pest control companies that can be purchased online for residential consumer use. According to its manufacturer, SenesTech, Contrapest is intended to be used as part of IPM.

Brookline’s Town Meeting could also ask the state legislature to let the town prohibit SGARs on private property as some other communities have done, Murphy added. Newbury, Arlington, Newton and Orleans have previously submitted home rule petitions that are now awaiting state legislative vote.

“These are really strong chemicals that are not regulated strongly enough, and we want local action and statewide change,” said Clint Richmond, a Town Meeting member, GreenSpace Alliance board member and conservation chair for the Massachusetts Sierra Club.

He believes restricting SGARs is just one step in an uphill battle to regulate pesticides, however, and cited PFAS chemicals in pesticides and first-generation anticoagulant rodenticides (FGARs) as ongoing issues as well.

“SGARs get a lot of attention because they kill raptors, which are a charismatic species, but eliminating SGARs won’t mean that pesticide problems are gone,” he said. “It’s just one facet of a much larger issue.”