Toronto pest control experts say they're seeing an unexpected silver lining to the COVID-19 lockdown: Reports of vermin like bed bugs and cockroaches are down significantly, thanks to physical distancing — but they say another kind of pest seems to be thriving: rats.

"Our calls specifically for rats have probably increased at least 20 per cent," since mid-March, said Dale Kurt, GTA regional manager for Orkin Canada.

"It definitely has increased a lot."

Jason Ward, a technician with Etobicoke-based Pesticon Pest Control, says he's also seeing a 20 to 25 per cent jump in calls from people who are seeing rats where they never had before, especially in residential areas.

Jason Ward, a veteran technician with Pesticon Pest Control, says he's noticed a drop in calls to eliminate the sorts of pests that are associated with person-to-person contact, like bed bugs and cockroaches. (Turgut Yeter/CBC)

"Because the restaurants and bars are shut, they have nowhere to feed so they're starting to spread out to the suburbs," Ward said. "They're looking for food, water and shelter, just like the rest of us."

The city stopped acting on vermin complaints on March 23 when Mayor John Tory declared a municipal emergency, city staff say. Only the most essential city services have been maintained since then.

Most bars and restaurants were shuttered by provincial order on March 17. That week, the city handled 14 rat calls — fewer than the average, according to city statistics.

And Kurt warns that for each reported sighting, many more rats are actually nearby.

"The rule of thumb: if you see one visually, there's probably 20 you don't see," he said.

But Kurt said the spike in calls he's getting doesn't necessarily mean there are more rats out there. "They're just more visible because they're on the move," he said.

Dale Kurt, of Orkin Canada, says rat complaints have risen by about 20 per cent since bars and restaurants closed their doors in mid-March. (Mike Smee/CBC)

He said his company's bed-bug calls dropped by 12 per cent in the first three weeks of April, compared to the first three weeks of March. Cockroach calls are down eight per cent.

Ward said he is seeing a similar drop.

"Because there's social distancing, other numbers are going down, like bed bugs and cockroaches, and those [pests] that are spread between people," he said.

To avoid rat problems, both Kurt and Ward recommend that homeowners do a simple survey around their properties.

"Part of it is removing the food supply, [and] doing structural maintenance," Kurt said, "sealing holes, having proper door sweeps installed to keep more from coming in, and then proper sanitation — keeping that food out of the way of easy access for rats and mice, so they will go to out baited traps more readily."

Kurt also pointed out that rats prefer cluttered areas, that offer easy hideouts.

Kurt recommends homeowners use what he calls the 'toonie rule,' while surveying their properties for potential rodent entryways. He says a rat can 'easily' slip through a hole the size of a toonie. (Orkin Canada)

"Rats and mice don't like to be in the open," he said. "They like to have hidden areas, whether it's under debris, under garbage. So keeping everything clean and tidy, up on shelves, really helps a lot."

He also recommends homeowners use something he calls "the toonie rule," when it comes to plugging holes that rodents can squeeze through.

"Anything the size of a full toonie, a rat will easily get through. The centre bronze coloured portion? A mouse will easily get through. So that's a good way to test, as you go around the outside of your home or business."

But once rats are established in an area, Ward says, it can be tough to move them.

Kurt advises people to clean up debris like this garbage pile in an alley off Queen Street East, because rats use them as hiding places. (Mike Smee/CBC)

He warns that even after the lock down ends and restaurants reopen, there's no guarantee the rats will simply return to their traditional hangouts.

"If they find new homes they might continue to populate within this region or this area, because they've found other sources to live off," he said.

"So it's a possibility that it might take years to come down:"