On Nov. 5, visitors to the Habitat Audubon site in Belmont noticed a great horned owl perched on a log. The raptor appeared lethargic and eventually fell from its low perch.
The bird was taken to an emergency hospital in Grafton, where it died two days later. A necropsy revealed it had died from ingesting poison likely consumed by the owl’s prey, rodents.
Not long after that, another great horned owl was found dead in a Cushing Square yard. A necropsy performed earlier this week also showed the bird had evidence of consuming rodenticide.
Each week, wildlife rehabilitators around eastern Massachusetts are flooded with sick raptors, most of which will eventually die from the poisoning. Raptors of all types are vulnerable: Two bald eagles have died in Arlington, for example.
Now, grassroots organizations are cropping up in towns across the state, with members targeting the use of rodenticides.
“We are driven by the wanton, unnecessary destruction of wildlife,” said Belmont resident Jeffrey North, a founding member of Save Belmont Wildlife. “We have a desire to educate people in the private sector and the business sector about the destructive nature of these compounds.”
At issue are rodenticides that cause internal hemorrhaging in rodents. The rodent eats the tainted bait, which may take a week before killing the animal outright. In that window, they are easy prey to hawks, owls, and eagles. Eat enough tainted rodents, and the raptor is doomed. The compounds can have lethal effects on mammals, as well.
According to North, Save Belmont Wildlife copies Save Arlington Wildlife, the brainchild of Arlington resident Laura Kiesel. Kiesel began working on curbing or eliminating the toxins in 2015, kicking it into a higher gear when a bald eagle was found dead in Arlington, a victim of rat poison.
“We started as a website and a movement to get people to write the select board and offer public comment to get (Town Meeting warrant articles) passed,” she said.
Kiesel said the warrant articles, which passed, banned the use of rodenticides in Arlington public buildings and called for a home-rule petition to ban their use on private property, as well.
The Belmont group has 11 members, including North, who writes the Belmont Citizens Forum. In its two or so years of existence, it’s gone through different activity levels, according to North. Right now, the “small but passionate” group is moving toward greater activity, he said.
The Problem
Data about the impact of rodenticides on raptors comes in two forms. There are two studies done a few years apart on red tail hawks. The first showed more than 80% exposed to rodenticides. The second study, about 10 years later, showed that number was closer to 100%.
Anecdotal evidence comes from the various dead raptors discovered and handed over for study. Kiesel said it’s hardly a representative sample, citing the fact birds often die out of sight, and those that are found are often disposed of without testing.
“Sometimes I’ll go a week or month without hearing something,” Kiesel said. “But now, I’ve had four dead owls in the past eight days.”
That count does not include the owl found at Audubon because Kiesel wasn’t directly involved, but one of the four was the owl found in Cushing Square.
“There is not good data out there,” said Sam Anderson, director of legislative and government affairs for Mass Audubon. “You have to find the bird, then find someone to pay for the necropsy.”
According to zooidaho.com, a great horned owl’s home range is roughly 1.5 square miles, much of it wooded.
Advocating for change
Anderson’s job at Audubon is, in part, to advocate for legislation to ban rodenticides. But that has proven a difficult task, he said. The pest-control industry is well-represented on Beacon Hill and speaks with a unified voice.
North and his group have found legislators supportive, but not, he said, enthusiastically so.
Now, the tactics to curb or control have shifted to groups like Save Belmont Wildlife.
“There are ways to deal with (rodents) that don’t include putting hyper-toxic compounds up the food chain,” North said.
Those include electrified boxes that zap the rodent to death, black plastic boxes containing non-toxic traps and even rodent contraceptives introduced through laced bait.
“There are towns all over eastern Massachusetts, signing on to the Save Wildlife movement at a steady clip,” North said.
Kiesel looks at a series of small victories as evidence her efforts to curb the poisons are working.
They have, she said, dozens of businesses that have banned the rodenticides; at least a half-dozen municipalities have moved to file home-rule petitions, allowing them to ban the use of the rodenticides on private property.
The Reason Why
North told the story of a group member who told him they once heard owls outside their window at night. Now, the owls don’t call anymore. The fear: The birds have died off.
“That is why we are doing what we are doing,” he said.
For Kiesel, the reasons are metaphysical and practical.
“There is an intrinsic value to our wildlife,” Kiesel said. “I think we are deprived of something, a piece of ourselves when we don’t have that access.”
Owls, Kiesel pointed out, eat about 5,000 rats and mice each year. Remove raptors from the equation, and you remove a crucial predator of the animal you are trying to control, she said.
“So, even if you only care about controlling the rodents, you are undermining your own efforts,” she said.
The Industry
David Flynn is president of the New England Pest Management Association, a volunteer group that counts about 200 members from all New England states.
“These rodenticides are a hot-button issue,” he said.
The poisons are a cost-effective, high-volume method of control, he said. That cost-effectiveness is important because many customers, including towns and housing authorities, are on a limited budget.
“If you set traps, you get one rat, and that trap has to be serviced again,” he said. “It gets very costly.”
However, the industry is trying to respond, he said. New rodent control methods, including filling burrows with carbon dioxide and bait laced with contraceptives, have shown some promise.
“We work hard to train our members,” he said. “The rodenticides are one tool, but it’s an important tool.”
There is movement on other fronts, as well, he said. More manufacturers are trying to remove the dangerous-to-bird elements from rodenticides, and the federal Environmental Protection Agency is studying them; depending on the study’s outcome, more restrictions could come to the use of the rodenticides, he said.
Banning them outright would, he said, mean an uptick in rodent populations, increasing their potential as disease vectors.