Rodents are big fans of garbage, which is why putting any outside garbage into an enclosed bin is important to keep their numbers down. (Dreamscape)
More food, more rats

Population growth and backyard gardens likely tied to increase in rodent numbers

Oct 21, 2022 | 3:53 PM

NANAIMO — Experts are coming to the conclusion initiatives to become greener, increase vegetation, home gardens and having backyard hens could be driving a rat population explosion.

Pest control technician James Sutherland said he’s been working on the Island for about seven years, and every year he has to deal with more and more rats.

“It’s just more and more calls, more population, people are continually seeing them more and more getting into their structures and homes, and just seeing them in their yards.”

While he’s not 100 per cent sure of the exact cause of the rise of the rats, he says it’s likely a multitude of factors, including denser populations and also people’s effort to become greener, especially after being stuck inside during the pandemic.

“Likely the push of people doing a lot more compositing, backyard gardening, having backyard chickens, which is basically just increasing food sources outside directly next to their home.”

He said the two most common types of rats on the Island are the roof and Norway rat, both of which can breed quite effectively year-round thanks to our temperate climate.

While rats are common, Sutherland said the classic house mouse is still the most dominant rodent.

“The way that the West coast kind of gardening is with lots of ground covering foliage close to the homes provides aerial cover against predators, habitat for them to breed and burrow into the ground.”

Sutherland said being a nocturnal animal, most people never see more than a flash of a rat tail as it escapes into a bush.

Dense foliage like this make great hideouts for rodents. (Jordan Davidson/NanaimoNewsNOW)

Animal Control Bylaw
When a new complaint-driven bylaw in Nanaimo was passed in early 2021 aimed at cutting down the number of cats at large, many residents were concerned the lack of roaming felines would increase the rat population.

Sutherland said he doesn’t think there is a connection, as most cats he’s seen are better suited to killing small birds than rodents.

“Mice and rats are pretty hard to catch unless they know specifically where a burrow or something is. So I would say I haven’t seen any kind of increase directly related to not having cats around. If cats were to catch rats or mice they’d probably only be able to catch one a night.”

Trapping rats is currently one of the only ways to cut down on their population, and with most traps only able to capture one rat at a time, it’s not the most effective strategy.

The use of pesticides are becoming increasingly rare, with a popular brand of rodenticide becoming banned in July last year.

Sutherland added home owners are the first line of defence against large rat populations.

Food sources, access to water and habitat are the key factors in making a property will be less inviting for rodents to live in.

Sutherland said without people making those changes or using pet and bird-safe traps, the rodent population will continue to flourish as our population grows.

“Or we can go back in time to a time before like, 1980 something and use first-generation anticoagulant rodenticides which require multiple feedings, are not very effective, and that’s pretty much the tools we have available as pest control professionals have become even more limited.”

A ban on those second-generation anticoagulant rodenticides was put in place from July 21, 2021 to January 30, 2023, with Sutherland saying they are likely to be permanently banned after the expiry date.

A national pest control company ranked Nanaimo in the 20thspot on their list of British Columbia’s “rattiest” cities, with Vancouver taking the top spot.

Vancouver also ranked second in the entire country, overshadowed only by Toronto who took the top spot

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