Somerville residents and wildlife experts are raising concerns over the high frequency of bird deaths over the past months. Two owls were reported dead in Somerville over a two-week period in December 2024 with necropsies revealing internal bleeding indicative of anticoagulant rodenticide poisoning, according to Laura Kiesel, the founder of the nonprofit Save Arlington Wildlife.
“If you extrapolate there are likely many, many more,” Kiesel wrote in an email to the Daily. “Most dead wild animals are disposed of by the city or residents or are scavenged by other wildlife.”
Somerville’s surrounding municipalities have also seen high rates of raptor death recently. Since the latter half of November 2024, Kiesel has been involved in the processing of 11 poisoned birds of prey in the area, including Arlington, Somerville, Cambridge, Belmont and Lexington.
“All of those birds exhibited some bleeding issues (which anticoagulants cause by stopping the blood from clotting),” Kiesel wrote.
Both city officials and environmental activists emphasized the need to protect raptors in Somerville because they are natural predators that help to keep rat populations in check.
“Raptors can eat hundreds and hundreds of rodents in a year,” Mary Vriniotis, co-founder of Save Somerville Wildlife, said. “And it’s hard to know how many rodents are poisoned by one particular bait box, but if you kept their predators alive, then that just seems like a more effective strategy.”
“It’s hard to come by urban predators,” Colin Zeigler, the environmental health manager for the city’s Inspectional Services Department, said. “Predators — especially for rats — need high canopy. They need a lot of canopy. And Somerville, as much as we like our parks and trees, there’s not a lot, so to see even one die as a result of something that’s preventable is concerning to us.”
Zeigler and Vriniotis both said that effective rat control requires reducing reliance on second-generation anticoagulant rodenticides to simultaneously address the root causes of bird deaths.
“This isn’t something that we can poison our way out of,” Vriniotis said. “We need to have much better waste management … because as long as there’s an easy food supply for the rodents, then having all the poison in the world doesn’t get anything done.”
“You cannot just irresponsibly throw bait around and expect any sort of results,” Zeigler said.
“Rats are a condition and an indicator of poor human practices and human health.”
The Inspectional Services Department is working to implement rat abatement strategies that reduce reliance on poison, including methods like SMART Boxes, which enable rat baiting and trapping without rodenticides.
“We handle cases on an individual level,” Zeigler said, “while discouraging the use of rodenticides as much as possible. That is the number one goal and objective of the city’s response.”
Zeigler acknowledges that while the city still uses rodenticides for larger infestations, they have shifted away from second-generation anticoagulants in favor of a Vitamin D concentrate.
“The issues with bioaccumulation associated with second-generation anticoagulants is significant and it’s a real concern of the city, so we have moved away from that,” Zeigler said.
The towns of Arlington and Lexington have already banned the use of second-generation anticoagulant rodenticides on public property, with Arlington implementing the ban in 2023 and Lexington following in April 2024. Residents and wildlife activists are pushing Somerville to take similar action.
“The environmental health coordinator and her supervisor have said that they were working towards removing [these rodenticides] from municipal lands, but we haven’t seen anything public and in writing to that effect,” Vriniotis said. “We don’t have any real data on what is going on behind the scenes with this city.”
“I think that the local Somerville government is appallingly negligent in this area,” a Somerville resident, who has been an active supporter of a second-generation anticoagulant rodenticide ban since assisting in the rescue of a poisoned hawk in 2023, said. “I think that the [Somerville City] Councilors have, for the past several years, brushed it off.”
Although no official action has been taken in Somerville, Zeigler confirmed that a ban on these poisons is under consideration.
“I’m concerned that overuse of these poisons is unnecessary, and a blanket ban would be within the interest of a healthier environment,” he said.
The city of Somerville has also discussed a Home Rule petition to bypass state restrictions and implement a second-generation anticoagular rodenticide ban on both municipal residential land, according to Zeigler. Lexington and Arlington have pursued similar legislation.
As the city considers a blanket ban, residents highlight the essence of holding community members accountable for proper rodent management and educating them on best practices.
“I think that there could be much more accountability with regards to trash and waste management and also guidance,” the Somerville resident said.
“I would say the biggest thing about approaching the rodent issue to avoid these types of incidents of secondary poisonings is to work as closely as you can with your community members,” Zeigler said.
