Rats!!! Rodent poisoning has long term impact on Worcester wildlife

Jenny Pacillo is thrilled with the amount of wildlife her family can see in their neighborhood of Burncoat.

“It’s such a treat – foxes, hawks. (I) didn’t expect to see so many animals in the city, but it’s very cool.

The mother-of-three opened up about the two neighborhood hawks and how they sometimes sit on her neighbour’s roof. “And two backyards from ours is an abandoned shed where a fox gave birth last year. There was a small pack of baby foxes.

She finds any type of bird fascinating. “I love crows, they’ll bring you presents if you’re on their good side. They love peanuts and cashews, so if you build a good relationship with them, they’ll bring you what they consider a gift, like string and rubber bands.

Jenny Pacillo, with her children, in March 2020.

But rats are another story. At first, she saw a rat at night that triggered the motion sensors. But it became a bigger problem during the summer, when the rats were running around outside in the middle of the day.

“I was forgiving at first, it’s part of city life.” Inspection services pruned some bushes, which helped until this winter, when the rats returned with a vengeance. Sometimes their traps catch three or four a night.

Worcester is dealing with an increase in rat sightings in recent months.

She believed the ongoing construction work on Burncoat Street may have agitated them and now there is so much of it that her children will run to the window to look for rats when the motion sensor goes off. It is difficult to control the problem of rats. “We use traps, but (we) have used poison a few times and it sucks because poison is the easier choice.”

It may be the easiest choice, but it’s not safe; in fact, it’s downright dangerous because rat poison moves up the food chain and affects all other animals.

Yenni Desroches, a former candidate for city council and an animal rights activist for more than a decade, agreed.

The use of rodenticide could have harmful effects on the environment.

“The four main rat poisons used are the ones that cause the most problems in the food chain, because they are the most powerful. They block the creation of the protein that controls bleeding and causes animals to bleed due to organ rupture.

The animals most at risk from rat poison moving up the food chain are raptors – hawks, owls, eagles and cats.

“There are ways to control the rat problem before resorting to rodenticide,” according to Desroches. Covered bins for trash and recycling will help, but the viable options for the city are really just trapping and prevention.

“Trapping is a never-ending battle and it’s not something we’re going to solve because we’re never going to get rid of it,” Desroches said.

With only three animal control officers they don’t have time so it’s at DPW and big projects like Polar Park only exposed the problems, which were always there but underground, so to speak .

Construction and other duct replacement projects displace rats, and people see them more because it removes the scent trails rodents use to navigate and they become disoriented. Chemical treatment of sewers has also been linked to the use of a deterrent that blocks olfactory pathways, which could displace them and lead to more rat sightings.

“It’s not that we can’t engage in construction, but we have to be aware that it will lead to seeing more rats. Moving them can help because it interrupts their breeding cycle as they cannot find a safe place to breed,” Desroches said.

Chris Spencer of the Worcester Department of Inspection Services confirmed that this is certainly an issue that needs to be addressed, but certainly not at the Boston or New York level.

Desroches recognized that these cities needed more urgent solutions. “In these kinds of situations, there really is no other option but rodenticide.”

A rat runs with a packet of poison pellets as others chase it through an infested warehouse in Gardner in 2004.

But Worcester’s levels are so much lower than other urban areas, she said. “We don’t hear people talking about how rats congregate in the street. It’s just, ‘oh, I saw a rat.’

“The methods we use,” Spencer said, “depends on state regulations and what’s effective.” The city has always done more baiting and trapping, not only because of the problem of poisons going up the food chain, but you can’t know for sure if they’ve handled the problem because you can’t always see the proofs.

“We don’t want to deal with the rat problem and create another problem,” according to Spencer. He explained how the city takes complaints as a metric, which it tracks through online and telephone complaint systems and has noticed a slight increase over the past year. The difficulty was that the garbage and rat complaints were categorized differently and they had to do a word search to find all the rat complaints, which were about 128. They took all of those and applied geographic information to identify hotspots or repeat calls, then overlay this map with other information such as construction projects. Resources will be pooled in these areas, be it education, baiting, etc.

American kestrals are one of the local predators that include rats in their diet - birds of prey are particularly vulnerable to the bioaccumulation effects of rat poison.  This one at the Ecotarium is called Newt.

“We’ve been developing this plan over the last three or four months, starting in September/October,” Spencer said. Construction now requires an assessment by a pest control expert before work begins and guidelines require restaurants to dispose of food waste so dumpsters don’t attract rodents and landlords must provide trash cans at the weather and rodent proof to minimize food source for rats. Owners can be fined for not providing them.

“We don’t conduct an annual rat count so can’t say if they’re on the rise or not, but once we started discussing it the complaints escalated quickly – maybe people didn’t know not where they could report their problems.”

Mass Audubon policy director Heidi Ricci weighed in on the public perception of the rat poison.

“People often see the rat poison as an easy solution, but it’s actually not the most effective and even counterproductive solution.” Mainly because rats don’t die right away. It takes a few days and during this time they weaken and stagger, becoming easy prey for predators, and there is enough poison in them to deliver a lethal dose to the predator that consumes them. Predators don’t reproduce as fast as rats so more and more rats and fewer predators.

Possums - the only North American marsupial - also hunt rats.  This one, Bear, was rescued and now lives at the EcoTarium and is a favorite with staff and visitors.

She agreed with Spencer that what works is sanitation – removing all sources of waste, litter and access to food sources like pet food, livestock feed, bird feed; exclusion — filling of holes in the foundation; and trapping. Some communities even distribute rat-proof trash cans, which can keep numbers down to much more tolerable levels. Cutting overgrown brush near structures will also help as rats can stay hidden and likely be more persistent in burrowing into foundations. “It’s a compromise,” she said, “because we want people to maintain more naturalized yards, but maybe not quite against your foundation.”

People living in urban areas should realize that it will never be possible to eradicate rats, but the goal would be to keep them away from areas of human habitation. Rat poison should only be used when other methods are not enough, as it creates more problems than it solves. Ricci cites the resurgence of raptors in urban areas since the withdrawal of DDT, but also notes that one of Worcester’s new eagles died last summer after consuming an animal that had been poisoned. “We don’t want to lose all of these raptors that we’ve worked so hard to restore.”

Rachel Davison, zoological manager at the EcoTarium, said all rats in Massachusetts are Old World rats and the house rat that is known as a pest here has been around for about 300 years.

“They were just introduced so long ago that they are established as part of this ecosystem.” Where there are humans, there are rats and mice, she says. “We just brought them everywhere with us, but obviously if someone sees a rat or a mouse in their home, that’s a bigger problem. But on the outside it’s probably due to the disruption – all the development going on in the city. At the EcoTarium, the rats that live on the property are part of the food system and there is no need to fear poisoning for large predators.

Davison noted how proud the people of Worcester are of the common Worcester hawks and pointed to the effect on local predators such as mountain lions, birds of prey and coyotes.

“Obviously when you have a lot of people you’re going to get parasites, but as human and animal habitats merge, larger predators come into contact with humans and rodenticides.”

The EcoTarium's resident skunk, Stormy.  Skunks are also vulnerable to rat poison transmitted to them from their prey.

The process of “bioaccumulation” in rats and mice or even smaller predators makes more poisonous for top predators. “People don’t think about it,” she said, “they just want to kill rats and mice. A study showed that over 80 percent of mountain lions had evidence of rodenticide poisoning.” She believes it’s because of a lack of education and encouraged people to think about the big picture: small decisions can have a huge impact on the overall environment.

Both Ricci and Davison noted that a bill in the state Legislature, An Act Relative to Pesticides (H.3991), would reduce the use of rat poison in the state. And they suggested concerned citizens contact their representatives to support the bill.

Desroches lamented that the bill didn’t get much traction, but praised the fact that the EPA also ordered guidelines, but did not officially ban poisons.

The state bill would further regulate rodenticides, making second-generation rodenticides available through pest control companies, and require better disclosure of alternative methods and the risks associated with pesticides.

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