Rats have always lived in Portland, but construction projects, an increase in composting, and now changes in restaurant service due to the coronavirus pandemic seem to be driving an increase in their population. (Courtesy Big Blue Bug Solutions)
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While the coronavirus pandemic forced most Portland residents to stay home for the past year, the city’s rats were pushed out of their homes and into the light. 

Rats have always lived in southern Maine. But in recent years construction, composting, and now the pandemic have increased the rodents’ population and changed their habitats.

On March 16, Portland resident Lori Thayer noted on the internet bulletin board NextDoor that she had seen a rat in her Massachusetts Avenue yard every day that week. Her post received 42 comments.

The responders agreed that rats are a problem in many areas of the city. Neighbors suggested a range of solutions, from burying the creatures underground with dry ice, using kitty litter to keep them away, or calling the city’s animal control officer.

Jeanne Muse commented that neighborhoods such as Deering, Rosemont, and Libbytown are “infested” with the animals.

“I simply urge folks to do their own research on this issue,” she wrote. “Rats are mostly nocturnal as well. Seeing them in the day is a clear sign there’s plenty more.”

Michael Cash of South Portland-based Big Blue Bug Solutions said construction projects, like the one at Back Cove, can displace rats and cause them to migrate to residential areas. (Portland Phoenix/Elizabeth Clemente)

Angela Jensen-Wickham of Ridgeland Avenue in South Portland has rats and field mice that her cat brings home from around the city’s oil tanks. This year, she wrote, seems to have been worse than ever before.

Oakdale resident Greg Bodlovick said he thinks the problem is “out of control” and he has “requested city action” on the city of Portland website.

Likewise, Angela Leighton said she has lived on Jersey Avenue in North Deering for about five years and had never seen rats before January. Since then, she has caught eight of the rodents on her property, she said.

The anecdotal evidence, it seems, is that Portland’s rat population is growing into neighborhoods previously believed to be immune from the problem.

Do rats get a bad rap?

Rats have a reputation for being disgusting, in part due to the widely held belief that they were the vehicle for spreading bubonic plague throughout medieval Europe and Asia.

In recent years, however, that notion has been challenged, with a 2018 study finding human parasites such as fleas might have been to blame, according to National Geographic.

Still, rodents are far from harmless, with the CDC reporting rats and mice spread 35 diseases worldwide.

At Northwood condominiums in North Deering, residents received an email last week that property managers would be launching a “rodent prevention program” by placing tamper-resistant bait stations on the property.

Michael Cash, an exterminator with the South Portland branch of Big Blue Bug Solutions, has worked in the pest control industry for 15 years. He said last week that there has been “a lot going on” with rats locally to drive their increased numbers in the past few years, and also that he has received more calls about rats in the past year.

Portland’s rat population was already growing, but the pandemic created more opportunities for them by promoting outdoor dining and restaurant closures, Cash said.

When many restaurants initially closed due to COVID-19 restrictions last spring, some left garbage in outdoor containers, which were not being emptied as frequently, thus creating a ready food source for rats.

Portland is not the only U.S. city where the pandemic exacerbated the rat problem. The New York Times reported last spring that New York City rats were becoming “more aggressive” with each other in the wake of COVD-19 restaurant shutdowns, exhibiting behaviors like eating each other’s young because there was less food available. 

Cash said when thinking of what attracts rats, people should remember that the rodents seek conditions conducive to their survival: food, water, and shelter. 

Rats’ need for a water source is one thing that differentiates them from other rodents, he said.

“If there’s old plant pitchers (in your yard) or a swimming pool or a tire, or anything that’s housing water, (it) can become a drinking fountain for the rat population,” he said.

More city restaurants offering outdoor dining have also contributed to the problem since people are more likely to drop food scraps on the ground that might not be picked up as they would indoors.

“You’re basically bringing that food source right outside,” Cash said.

More people have also been cooking more meals at home instead of going out during the pandemic, he said, which generates more garbage on their properties that rats can eat.

Another factor is the rise in popularity of composting. Especially on what Cash called “the outskirts” of Portland, where many single-family homes exist, people are composting and sometimes using flimsy containers that are easy for rats to chew through. 

That’s an “additional food source … for the rat populations and even squirrel populations, and other rodents,” he said.

Instead of using plastic bins, Cash said, composters should use secure metal or wood containers that rats cannot chew through.

Home alone no longer

Ruthann Weist, animal control officer for the Portland Police Department, said she and her roommate recently had rats burrowing under their chicken coop and have stopped tossing old food in the woods for composting.

Weist said the anecdotal increase in rat sightings in Portland could be the result of several factors, including that people are noticing rats on their property more often simply because they have been home more during the pandemic.

Another could be the natural predator-prey cycle. With all animals, she said, there are times when there are not enough predators to keep the prey at bay.

In the case of rats, Weist said, a decline in predators could be the result of people using rat poison, which also kills animals like hawks, owls, foxes, and coyotes that prey on rats. 

Weist noted she does not handle calls about rats, which typically fall under the domain of code enforcement because of the frequent relationship to trash buildup on private property.

Dena Libner, chief of staff for Portland’s executive department, said via email April 23 that the city has not seen an increase in the number of complaints about rodent activity and that it does not provide rodent mitigation services for private property owners.

Libner offered another reason, however, for more rodent activity in town.

“I can tell you that construction projects can cause rodents to seek out new homes and result in an increase in observed activity, especially when construction is occurring in a formerly vacant space or underground,” she said.

City spokesperson Jessica Grondin did not respond to follow-up questions about whether the city has plans to mitigate the rat population in the coming years. Grondin also did not answer a question about whether construction projects like the sewer separation work being done near Back Cove have safeguards in place to deal with displaced rats or other wildlife. 

In response to similar questions, South Portland City Manager Scott Morelli said via email April 30 that his city has received “occasional” complaints about rodents, with some people attributing the sightings to construction projects.

When the city has had complaints about rodents on city property such as parks, Morelli said, staff has worked with a local exterminator to plant traps. He also said city staff has educated some homeowners about how to prevent rodent problems.

Morelli also added he believes some city construction projects have required contractors to provide some form of rodent control.

Cash said as the Portland area continues to grow, more people also means more opportunities for rats to thrive. Portland is a city that he said has “outgrown itself,” and with more people moving to surrounding towns the rats are bound to follow.

He also noted that like all cities, Portland’s sewer system and the “integrity of the structure” are degrading over time. As things break down, he said, rats burrow and make dens in areas of the sewer system “where the structures are not as sound as before.”

The bottom line, he said, is rats are opportunists.

“The more we take away their natural homes,” he said, “(the more) they come into what we’ve created as homes.”

Portland resident Liesse Thibeault posted this photo on NextDoor, advising people to use snap traps instead of rat poison to avoid poisoning other animals. Portland Animal Control Officer Ruthann Weist agreed. (Courtesy NextDoor)

What to do if you have a rat problem

Frustrated or freaked out by the sight of rats near your home? Experts in greater Portland advise people to stop creating conditions for the animals to thrive.

Michael Cash of the South Portland branch of exterminator Big Blue Bug Solutions said that means people should make sure their houses are sound enough to prevent the animals from gaining shelter.

The national extermination chain Terminix said that means plugging up any exterior holes in your home that are larger than a quarter of an inch, trimming tree limbs to ensure rats cannot climb to the upper areas of your home, and not leaving food out inside your house, which includes cleaning crumbs from areas like behind the toaster.

Yard maintenance also helps keep rats away, according to Terminix: cleaning up pet feces in the yard, ensuring litter boxes are clean, and picking up decaying fruits or nuts that might have fallen off plants.

Pet owners should also feed their animals inside the house and keep their water bowls indoors. Stacking firewood away from your home and only keeping as much as you need is also recommended, along with storing trash and compost in tightly sealed containers.

Portland Animal Control Officer Ruthann Weist advised against using rat poison because it can also poison rats’ natural predators, which allows the rat population to grow.

Glue traps or Tomcat kill traps should also be avoided, Weist said, because they have a tendency to “severely injure raccoons and skunks.”

If rats are inside your house, Weist said, the best way to get rid of them is with snap traps, instead of trying more humane options.

“Unfortunately rats are smart enough. They tend to avoid humane traps,” she said. “Mice are a lot more likely to go into a humane trap than a rat.”

— Elizabeth Clemente