After rising steadily for the past three to five years, the GTA’s rat population appears to be in the midst of a boom.

With people now out gardening and hosting backyard barbecues, they’ve started to notice rats scurrying around — or nests, droppings and the like — and have turned to companies like GreenLeaf Pest Control, where calls for the beady-eyed rodents are up 30 per cent over last year.

“Yes, 100 per cent we’ve noticed an increase,” GreenLeaf’s Daniel Mackie told CityNews.

“This year in particular, there was a tremendous increase. It’s quite substantial.”

Mackie blames the milder winters, the availability of food from compost bins and vegetable gardens, and a lack of predators. Rats may also be more visible in areas where construction projects have disturbed their nests, he adds.

Plus, as the City of Toronto puts it, “Large urban environments provide excellent habitats for rats to survive and thrive.”

The rats we see in Toronto, the Norway or brown rat, may be the most common mammal in the world, according to an article in Toronto Life. They came to North America from Europe in the 1700s and have an incredible ability to procreate. One pair of rats, the article notes, has the ability to produce 15,000 descendants in a year.

“As the weather is warmer and winters are milder, there’s more abundance of food — and more activity,” Mackie said.

“The rodents are active longer and not going into winter slumber. There’s more love that’s happening.”

Mackie says there are three things you can do to make your yard hostile to rats, which chew through wires, urinate and defecate with aplomb, and spread bacteria, allergens and disease.

Inspect your home and yard for possible entry points — gaps around pipes, missing bricks — and seal the gaps with concrete or steel wool. Keep vegetation 12 to 18 inches away from your house. The open space makes rodents feel vulnerable to predators. Get rid of debris in your yard, like piles of wood, or at least don’t place it against your house.

“Rats don’t know you don’t want them,” Mackie said. “The reality is they’re part of nature too.”

Find more rodent-control tips from the City of Toronto here.