Warm winters are to blame for the fast-growing rat population in Ontario.

Mike Heimbach with Abell Pest Control said they've seen a 26 per cent rise in calls for rats over last year.

He said in Kitchener, Waterloo and Cambridge, the number of inquiries this year is up 115 per cent, and last year they were up 60 per cent.

People living in Cookstown, near Barrie, have blamed ongoing construction of a new subdivision for the rats running rampant in their homes and on their properties.

But Heimbach said the increase is weather driven.

"Two winters ago, we had an abnormally warm winter, and we didn't get the kill off that we normally get, so we had more rats breeding," he said.

"And then, last winter, again we didn't get the kill off, so even in the spring of this year we saw an absurdly high rate of rats."

Heimbach gave the following advice to anyone wanting to rat-proof their home before this winter sets in:

Clean up your yard

According to Heimbach, a clean yard that is free of debris is very unattractive to rats.

So clean up compost, put leaves in bags, and remove standing water, including bird baths.

You may also want to remove or limit the number of bird feeders from your property, as they can attract rats.

He said a friends mother recently called him when she looked outside to see "three rats hanging off her bird feeder, trying to get in and up at the bird seed."

Rats depend on humans to live, so it's important to be aware of anything that could help them survive. 

Pizza Rat

Heimbach said rats depend on humans for food and shelter, which is why home owners need to rat-proof their properties before winter. (YouTube/Matt Little)

Fill in holes

It's important to replace vent covers and stuff copper mesh into any open spaces on the outside of your house.

"A rat can get through a hole the size of a quarter, a mouse can get through a hole the size of a dime," Heimbach said.

However, if you suspect a rat is inside the house, set a trap near the hole before eliminating the only way back out of your walls.

Heimbach also encourages home owners to take a look at their garage door, to ensure it's sealing properly.

CBC K-W contributor Barbara Robinson of Norton Engineering also tweeted if you have a downstairs bathroom, keep the lid closed and maybe even put a brick on top of it.

"Rats can walk up your sewer lateral and swim through [a] toilet trap," she said.

Don't trap them

Glue boards are cheap, but Orkin Canada warns a strong rat is often able to pull itself free.

As for snap traps, if a rat doesn't get caught in it, they learn to avoid them in the future.

Covered, electronic traps are expensive and must be emptied and recharged after each catch, while humane traps will catch rats, but releasing live rats just transfers the problem to another area.

"Avoid the hassle and health risks associated with cleaning out rat traps by leaving removal to the specialists," Orkin Canada suggests on its website.

Rat in downtown Toronto

An increase in rat infestations has been linked to colder weather and frozen ground, because the rats go inside to stay warm. (Bruce Reeve/CBC)

Trim your trees

Rats don't just stay on the ground, so make sure tree branches aren't touching your home.

"[It's a] great opportunity for a rat to run along the top of a tree branch, to jump on your roof and shoot down your chimney," Heimbach said.

Hope for a cold winter

This is the one thing you can't control, but Heimbach said a harsh, cold winter is necessary to slow down the rampant growth of Ontario's rat population.

That said, a cold winter makes it even more important for homeowners to rat-proof their properties, because the rodents will be extra keen to find a warm place to wait out the snow.