At the New England Wildlife Center in Weymouth, veterinarian Priya Patel checks the vitals of one of her patients. He’s a red-tailed hawk, and for the moment he’s swaddled in a sandy brown towel.
When this bird of prey was first admitted several months ago, he was bleeding, bruised and barely able to stand. An X-ray revealed no broken bones — an important clue about what is going on.
“ To have an impact that causes that amount of bruising and swelling, but doesn’t break the bone, tells you that something’s wrong with [the body’s blood] clotting mechanism,” Patel said.
His diagnosis? He ate too many rodents with rat poison in their bodies. This type of poison, called anticoagulant rodenticide, prevents a rat’s blood from clotting normally. Its effects can also be fatal for birds — or any animal that eats rodents.
Even when it’s not fatal, the poison can build up in animals’ bodies and make it difficult for them to heal from injuries.
There’s no cure. So the vet team has to wait for the hawk to flush the poison from its system naturally, which can take months. They support the natural process by injecting the hawk with vitamin K.
The Weymouth hospital treats thousands of animals annually, and almost half its patients are birds. Patel said the staff is usually treating at least one animal for poisoning at any given time.
“Every bird will be exposed at some point in their life,” Patel said. A study of more than 40 birds of prey admitted to the Tufts Wildlife Clinic found that all red-tailed hawks had some amount of this poison in their bodies.
This type of rat poison is so prevalent because it’s among the most cost-effective ways for exterminators to deal with rodents. But Maureen Murray, director of the wildlife clinic at Tufts University’s Cummings School of Veterinary Medicine, said there are methods that work better and are less likely to harm wildlife.
If rat poison were the answer to cities’ rodent problems, we would’ve eliminated rats by now, said Murray. “Solving the issue of rodent problems goes beyond using poisons.”
‘A people problem, not a rat problem’
In a Burlington park, exterminator Robert Linscott opens his bait box to find a gooey mess. Some of his homemade, organic rodent bait has spilled out of its containers.
This sticky concoction is key to Linscott’s poison-free method of pest control, developed for his company North Shore Wildlife. Instead of setting out toxic pellets, he catches rodents with a specially designed system of tunnels and snap traps lined with this bait.
For each job, he tailors the ingredients to what his customers tend to eat and throw in the trash, where rats feast on the leftovers. Some of his go-to ingredients include molasses, peanut butter and chocolate. Linscott said he even buys five-gallon tubs of bacon grease to make the mixture irresistible to rodents.
The bait is just one of his strategies. Linscott said good exterminators also talk to their customers about how to manage food waste and address holes in buildings that allow rodents to get in.
“ If you’re not addressing the problem, which are the holes and the gaps and the entry points, and you’re just putting bait boxes down, I don’t know how effective that is,” he said.
Most pest control companies are trying to move away from poison, said Galvin Murphy who runs Yankee Pest Control in Malden.
“ I feel that we have a people problem, not a rat problem,” he said.
Murphy tries to educate his customers about what’s attracting rats in the first place, making suggestions on how to keep trash secure or address landscaping that might look welcoming to critters.
“ If we get people to go along with our recommendations like that, we can often gain control for the long term, because we certainly don’t want to just keep throwing poison out to kill these animals,” he said.
Boston takes a similar approach to public buildings, said John Ulrich, the city’s assistant commissioner for environmental services. He oversees rodent control on public property and prefers to avoid poison.
While the department sometimes uses carbon monoxide to kill rodents living in burrows, Ulrich said lethal poisons aren’t the most effective way to address the problem.
“ Food is really the main driver of rodent activity,” he said. He advises residents to tightly cover garbage cans and not leave them outside overnight.
“It’s trying to get folks to understand the connection between how their behavior affects rodent populations,” Ulrich said.
‘Nature’s best solution’
Advocates are pushing for a bill in the state Legislature to restrict when and where rat poison can be used in Massachusetts. The measure would limit any use of this type of poison to public health emergencies.
But critics say the bill goes too far.
“If this bill, the way it’s written, passes, we’re losing a very important tool in our toolbox,” said Murphy, the exterminator in Malden.
He worries that restricting use of poison would drive up costs for customers, such as those living in affordable housing, and could push them to take matters into their own hands.
Many poisons used by commercial exterminators can be easily purchased online. But without a licensed professional, Murphy warns, consumers can inadvertently harm wildlife, pets and children. According to America’s Poison Centers, thousands of children are exposed to rodenticides each year.
The proposed legislation wouldn’t address online sales, said Dave Power, a project coordinator in environmental health and the unofficial rat czar for Cambridge. But he supports the idea of putting some legal guardrails on rat poison.
“ There’s a need, right? For regulation, for some sort of oversight,” Power said.
Currently, a patchwork of local ordinances and bylaws partially bans the poison on public property in many cities and towns, after local wildlife advocates pushed for limits in recent years.
Lexington resident Marci Cemenska, who has advocated for restrictions in her town, said people who hire pest control companies often aren’t aware of how this poison affects wildlife, in addition to pets and children.
But once they learn, she said, they usually support efforts to restrict it.
“This is a big issue. But somewhere in there, I’ve always felt like this is something that we can do something about,” Cemenska said.
A version of the statewide bill stalled last year. So Carol Disney, an advocate in North Andover, said she’s not waiting for state lawmakers to take action. She plans to keep pushing for more city and town restrictions.
“ This is a time when maybe we could do something on a local level that will really make a difference,” she said. “ By killing raptors, such as eagles, hawks and owls, we’re just throwing [away] nature’s best solution for rat control.”
Birds of prey eat thousands of rodents every year, said Zak Mertz, CEO of the New England Wildlife Center.
“ We can work with nature to solve rodent problems,” he said, adding that using poison “doesn’t do us or the environment any favors in the long run.”
‘Hard reality’
In mid-March, after more than 100 days at the Weymouth animal hospital, the veterinary team was finally ready to release the red-tailed hawk back into the wild.
They carried the majestic bird to the edge of the facility’s parking lot and unfurled the blanket covering him. The speckled hawk took flight toward a nearby forest in front of a crowd of cheering staff and wildlife advocates.
But it’s a bittersweet milestone. The hospital team is almost certain the hawk will ingest a poisoned rat again.
“ Doesn’t matter where in the state we choose [for the raptor’s release], as a bird that hunts for a living, it will most likely get exposed again,” Mertz said. “And that’s a really hard reality to come up against.”
This article was originally published on WBUR.org.
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