Becky Thomas of Caribou has been trapping and releasing large river rats like this one since she began spotting them in her basement in May of this year. Credit: Courtesy of Becky Thomas

CARIBOU, Maine — In the 39 years that Becky Thomas has lived on Fontaine Drive in Caribou, she has never seen rats in the neighborhood.

Not until May anyway.

Thomas first saw a river rat in her basement. Then the creatures, “as big as guinea pigs,” began popping up in her stock room and on her back deck. When Thomas realized that the rats were eating food left in dog bowls outside, she began feeding her four dogs inside.

But the rats kept coming.

Rat populations have been rising in Maine since the pandemic, with many taking advantage of increased takeout food left over in garbage cans. Old Town and Milford have taken drastic measures to exterminate rats after residents publicly complained. In both cases, residents were taking it upon themselves to set special, often expensive traps, and dispose of rats rather than wait for officials who they accused of not responding quickly enough.

But making the issue worse in Caribou are the many blighted properties scattered throughout the small city. Though officials have made tackling these homes a priority, they have still found themselves receiving numerous complaints about rats that are likely populating near vacant properties and those with garbage piled in the yard. The quick reproductive rate of rats means that populations can grow in a neighborhood even after homeowners take care of garbage and other property issues.

Take 52 York St., located just behind Thomas’ home, for example.

This home at 52 York St. appears (above) as a blighted property and (below) after its owner took care of some property issues. Neighbors suspect the site might have contributed to the growing river rat population. Credit: Courtesy of Caribou Code Enforcement Office (top); Melissa Lizotte | Aroostook Republican (bottom).

Owned by an out-of-state landlord, the house sat vacant for many years. When the most recent tenants left, neighbors complained to the city about garbage piled in the yard and the tall grass they believed was helping to feed and shelter rats.

The landlord has since removed the garbage, cleaned up the property and is looking for a new tenant, said Ken Murchison, Caribou’s code enforcement officer.

But that’s just one house out of likely hundreds in equal or worse conditions.

“If you looked on my desk right now, you would see a dozen notices of violation [to be sent out]. We constantly take calls from concerned people and we do our best to keep up,” Murchison said.

Since Thomas did not have the heart to kill the rats that invaded her house, she began releasing them past the Aroostook River, more than 2 miles away, after trapping them. Those efforts soon became time consuming.

“I would make two or three trips a day sometimes, which is hard because I also work,” Thomas said.

She has never found out for sure where the river rats came from.

Either way, she said, the city has largely left her and neighbors on their own.

Becky Thomas of Caribou has been trapping and releasing large river rats like this one since she began spotting them in her basement in May of this year. Credit: Courtesy of Becky Thomas

This month, Thomas started buying guillotine-style traps that draw in the rats with food and then kill them. Between her previous traps and these, plus candy she uses to bait rats, Thomas has spent close to $100.

So far Thomas has killed one rat with the guillotine traps and has shared those contraptions with her next-door neighbors, Dianna Cameron and her son Mikal Cameron, who said they have also found river rats in their garage.

Many of the rats Thomas previously trapped were entering her cellar and basement by chewing holes through the home’s wooden beams. Thomas has since filled the holes with spray foam insulation, which seems to be working.

But Thomas, who said she has spoken with Murchison three times since the problem began, remains frustrated with the lack of more drastic rat control efforts from the city.

“I’m not sure what they can do except tear down more of these old houses,” Thomas said. “I know I’m not the only one [dealing with this], but no one ever talks about it.”

Unfortunately, Murchison said, any efforts to deal with rats largely fall on homeowners.

Since rats are wild animals, any population control or other measures fall under the expertise of the Maine Department of Inland Fisheries and Wildlife, not the city.

“Our animal control responsibilities are generally related to dogs and cats,” Murchison said.

When he does hear from concerned residents, Murchison usually tells them to avoid feeding stray dogs and cats and wild animals, keep garbage inside and dispose of it regularly and keep lawns well maintained.

What the city can do is continue fielding calls from concerned residents and make sure problem properties can either be remedied or torn down if necessary, he said.

“Whether all of the [blighted properties] are causing river rats, I cannot say,” Murchison said. “Ultimately, it becomes up to property owners to eliminate conditions that attract and hold rodents.”