In Idaho’s Treasure Valley, residents confront ancient pest
Chloe Baul
BOISE, Idaho (CN) – A few months ago, property owner Melina Gritton got a troubling call from a tenant at a trailer park in a working-class part of Southwest Boise.
Something, the tenant told her, was chewing through the walls.
Gritton’s trailer park had a rat problem. “As I started investigating, it was widespread,” she said. “We have spent about $20,000 trying to get rid of them.”
At first, an exterminator was skeptical. Rats haven’t historically been a big problem in Idaho, where winters are cold and human populations were for decades pretty small.
“He said, ‘No, it’s not rats. It can’t be,’” Gritton recalled. “My tenants started catching them, so we could show him.”
The evidence quickly became hard to ignore. In some cases, Gritton said the rats caused so much damage that she had to replace entire walls.
“A mouse can’t eat through a wall in two minutes,” Gritton said. “I assure you, a rat can.”
For basically as long as human civilization has existed, rats have been a scourge, damaging property, ruining food supplies and spreading disease.
In many big cities, it’s a problem that continues even today. Exhibit A: Pizza Rat, New York City’s most iconic rodent celebrity.
Still, for many people in the Treasure Valley, a region that includes Boise, rats have long been a problem for somewhere else.
Then came black and brown rats. They’ve become a major problem in recent years, spawning community groups and even an effort to crack down through legislation.
No one knows for sure how they arrived — but there are a few theories.
Scott Rogers, co-owner of Wild West Pest Control, mentioned one involving escaped rats from a middle school in the city of Eagle. He observed that one of his first rat jobs was about a mile from the school.
So far, though, no one has been able to confirm that hypothesis — and it may not be the most simple. Rogers also noted that rats can travel by hiding away on shipping pallets or other transported goods. It’s a less exciting theory but one that mirrors the history of human-rat relations, as the pests have often spread by stowing away with humans.
Whatever the cause, stories like Gritton’s have become increasingly common across Treasure Valley as the infestation has spread. Rats have shown up in yards, garages and crawl spaces.
Sightings have been steadily growing — and the pests can be aggressive. As Gritton has worked to repair her trailer park, she said the rats living there have confronted her. “They literally hissed and chased me.”
In the upscale Boise suburb of Eagle, resident Jane Rohling said she first noticed rats on her property in 2022.
She soon started hearing stories from neighbors as well.
In 2024, Rohling created the online group “Rats in Eagle and Beyond,” allowing residents to vent, share tips on trapping and prevention and alert others when rats seem to be spreading. It now has more than 1,000 members.
Besides offering tips and community support, Rohling is also preparing a survey aimed at gathering more detailed information about rat sightings. As officials consider how to respond, she hopes the results can help lawmakers and agencies understand how widespread the problem has become.
Although rats have likely existed in small pockets in the region for decades, locals say the problem has exploded in just the last three or so years. “I first had rats in my yard in the fall of 2022,” Rohling said, “and have been trapping a few each year ever since.”
A review of Rohling’s group captures the rat panic that has swept the Boise area in recent months.
In one post from March 7, Boise resident Janelle Wise reported she’d seen a group of rats crossing the street.
“Rats!” Wise wrote. “On my way home from Boise High tonight, I saw them crossing Warm Springs Avenue.” It’s unclear why the rats were crossing the road, but they presumably made it to the other side.
In an email, Wise said she plans to set traps and secure food sources around her property.
“I’ve lived in this neighborhood for 47 years and have never seen rats before,” Wise told Courthouse News. “I am getting traps and already have chickens, which will go after them.”
Pest control professionals say several factors make the Treasure Valley an appealing home for rats.
Urban growth has expanded housing into formerly agricultural and undeveloped land, pushing rodents toward neighborhoods and buildings. Irrigation canals, greenbelts and dense landscaping — all of which are prominent in Boise — provide protected travel routes and hiding places.
“In the wintertime, [rats] use the dry canals to navigate throughout the urban area,” explained Scott Rogers, the Wild West co-owner.
These days, Adam Schroeder, director of Ada County Weed, Pest and Mosquito Abatement, estimates his office gets between two and five calls per week from concerned residents. They come from all over the county.
“Most of the calls that we’re getting are from landowners or property owners, homeowners that are trapping rats or that are noticing rats in their neighborhoods,” he said. “Some of them say they’re trapping 12 to 20 rats within a matter of a couple of weeks.”
Despite the complaints, Schroeder said his agency has limited authority to address the issue. Currently, rats are not formally listed among the pests the county is authorized to control.
Even so, Schroeder acknowledges that without coordinated action, populations will likely continue expanding.
“If we don’t have any kind of control measure, they will certainly spread,” he said. “The problem will certainly get worse and more expensive to deal with.”
Rogers likewise says he’s seen a steady increase in rat calls in recent years.
“It’s been picking up ever since the initial outbreak was reported,” he said. “Just the fact that your home exists makes your house a target for rodents.”
Boise and Eagle seem to be hotspots, Rogers said. He’s urging residents not to underestimate the problem.
“I think that’s the one thing that people get wrong about rats is, they tend to think of rats as just big mice,” he said. “That’s totally wrong.”
Because of their size and strength, rats can chew through wood, plastic and wiring. Damaged electrical wires can create fire hazards, while chewed plumbing can cause flooding. All of it creates economic loss.
On top of that, rats reproduce quickly and are difficult to trap. A pair of breeding rats can create thousands of offspring in a year under ideal conditions, Rogers said.
Their intelligence also makes them cautious around traps and bait. Unlike mice, which often approach traps immediately, rats tend to avoid unfamiliar objects until they are certain they are safe.
This behavior, known as neophobia, makes do-it-yourself control methods less effective.
“You have to play mind games with rats in the initial stage,” Rogers said.
The scale of the problem has prompted calls for state lawmakers to step in.
In March, Senate Bill 1271 landed at the House Agricultural Affairs Committee.
The measure would have declared rats a public health nuisance, adding black and brown rats to a list of agricultural pests and invasive species while also directing state and local officials to map infestations and develop a statewide mitigation plan. The bill passed in the Senate but never made it out of the House, disappointing those who say Idaho’s rat problem needs quick and coordinated action.
Even with organized efforts, experts say rats are unlikely to disappear completely.
In Boise — as with much of human history — the pests by now might just be here to stay.
“Personally, I don’t believe that we could ever really exterminate the rats,” Rogers said. “We’re probably going to have them forever. I don’t think we’re going to be able to stop their population growth — but I think we can stop them in areas where we need to suppress their population.”