If Evanston could hire the Pied Piper of Hamelin, City Council would not have to discuss a subject that gives everyone the willies: rats. But indeed, at the Feb. 6 City Human Service Committee meeting, Rodent Control Update had a place on the agenda.

Rats are not a new problem in Evanston, and those black plastic bait stations are a common site in alleys and behind grocery stores and restaurants. For Evanston residents who face rat problems, the City’s Health & Human Services Pest Control website provides tips for identifying, preventing, and managing rat activity, and offers a downloadable brochure called “Controlling Rats.”

“This is a collaborative effort, and there are a number of things that our residents can help with in controlling the population of rats,” says Ike Ogbo, Public Health Manager, who encourages residents to call 311 if they find rat burrows or see something that doesn’t look right sanitation-wise around the City. “We do rely on the public to let us know about issues in our area.”

Evanston’s Public Health Department handled local rodent control until the City hired an outside pest control operator in 2012, Mr. Ogbo says. When residents call about rat activity, the City inspects for factors that attract rats, such as overflowing garbage, trash bins with holes, tall grasses where rodents can hide, dog feces, bird feeders, and dilapidated structures that allow rats easy access. When needed, the pest control company takes care of rat elimination treatments, usually with bait stations. The City also uses ward meetings and area newsletters to help inform residents about rodent control, says Mr. Ogbo, and has revised how 311 handles questions about rodents. 

Feed a Cold, Starve a Rat

Two Evanston residents spoke briefly at the Feb. 6 meeting, stating that easy food access attracts rats.

“The way to get rid of rats in Evanston is to close our garbage cans and clean up our streets,” said Teresa Horton, Ph.D., a professor with the Center for Reproductive Sciences at Northwestern University who has spent much of her career studying reproduction in rats. “For every 10 percent reduction in calories that a rat does not get, she spontaneously aborts one fetus,” Dr. Horton said at the meeting. “If you want to control rats, you control food.”

Common rat management methods include poisons, trapping, and blocking rat burrows. But rats are smart and quickly learn to avoid traps and baits, said Larry Heaney, Ph.D., who also voiced his concerns at the City Council meeting.

“If they see another animal eat poison and die from it, they will not go near poison for the rest of their lives,” said Dr. Heaney, Curator of Mammals at the Field Museum of Natural History and co-chair of the museums’ Pest Committee. Likewise, if they see an animal die in a trap, they will not go near a trap again, making the impact minimal and short-term. “The only way to remove the problem, or to reduce it significantly, is to remove its source of food,” Dr. Heaney said.

Rat Basics

The rats typically seen scurrying through dark alleys or huddling near garbage cans are brown or Norway rats (Rattus norvegicus), an apparent misnomer since the nocturnal rodents do not originate from Norway. They have lived with humans probably since agriculture began 10,000 years ago in the middle east, says Dr. Heaney, and they unwittingly migrated to North America on European ships in the 1600s.

Rats live two to three years and breed prolifically, with females producing up to 60 pups per year over seven or more litters. If the food supply wanes, female reproduction slows to accommodate; conversely, abundant food ensures plentiful offspring.

Street rats notoriously carry diseases such as leptosporosis, salmonellosis, and hantavirus, so public health departments constantly seek novel and effective rat-control methods. One method raised at a recent City Council meeting involves feral cats, with which the Sherman Gardens Apartments complex just north of downtown Evanston has experimented since May of 2016.

The Feral Cat Dilemma

Sherman Gardens residents provide shelter, food and water for two feral cats they adopted from the Tree House Humane Society, whose “Cats at Work” program neuters, vaccinates and adopts out small groups of feral cats to help control rodent populations. Tree House reports they have placed nearly 600 “working cats” in city and suburban backyards, barns, condo buildings, factories and warehouses. According to the September 2016 Sherman Gardens resident newsletter, their “rat patrol cats,” Sweetie and Stinky, “are happy and healthy and keeping our rats at bay for the most part.”

But a 2009 Johns Hopkins University study concluded that cats kill mostly juveniles and do not rely on rats for food, so their predatory habits have little impact on the adult rat population. Donnie Dann, of the Bird Conservation Network, presented information at a recent City Council meeting arguing that feral cats pose a greater threat to local birds and small mammals than they do to rats. Mr. Dann also shared American Bird Conservancy summaries of Trap/Neuter/Release (TNR) studies, which concluded that TNR programs “fail to reduce feral cat populations and negatively impact people and wildlife.”

Who Dares to Have a Pet Rat?

Those who can get past the rodent part usually find rats make good pets, says Hannah Horwick, an Evanston Township High School graduate who worked at Thee Fish Bowl for several years. Ms. Horwick keeps four black-and-white “hooded fancy rats” (a domesticated version of the brown Norwegian rat) in her Rogers Park apartment – in cages, of course. Rats are friendly and social like a cat or dog, she says, and like to hang out. They can be trained to do tricks, learn their name, and even use a litter box.

“They’re really awesome animals,” Ms. Horwick says. “They smell, the way ferrets do, but they’re loveable.”

Join the Rat Patrol

Chicago recently enjoyed the dubious distinction of being named Orkin Pest Control’s “rattiest city” (ranked by the number of rodent treatments in 2016), ahead of New York, Washington D.C., and Los Angeles. To prevent that from happening here in Evanston, the Health & Human Services department offers the following tips, with more at http://tinyurl.com/evanston-pest-control:

* Look for Evidence: nests or burrows, droppings, holes or gnaw marks, rub marks on walls and in the grass.

* Clean Up: get rid of clutter, control weeds, shrubs and bushes, wash away droppings and track marks

* Eliminate Sources of Food: seal and manage your garbage, and keep all food in tightly sealed containers.

* Shut Them Out: seal cracks and small holes in doors, fill large gaps and holes in walls and foundations, close inactive burrows

* Bait and Treat: Call 311 or hire a pest control company.

Meg Evans

Meg Evans has written science stories for the Evanston RoundTable since 2015, covering topics ranging from local crayfish, coyotes and cicadas to gravitational waves, medical cannabis, invasive garden...