Rat prevention and control

Overview

Rats are the most destructive vertebrate in the world. Globally widespread, rats cause major economic losses to stored and infield crops, destroy property, and transmit diseases, including Rat Bite Fever, C. difficile, E. coli, Leptospirosis and superbug bacteria.

The Norway rat (Rattus norvegicus) is the most common species of rat on the Canadian Prairies. 

Alberta’s Agricultural Pests Act, and Pest and Nuisance Control Regulation, lists the Norway rat and any other rat from the genus Rattus as declared pests. While the province is responsible for the administration of the Rat Control Program, every person and municipality , must take active measures to prevent the establishment of rats on their property. Under the Act, it is also illegal to import and sell rats in the province or keep them as pets.

Rat Control Zone

Norway rats directly depend on the presence of people. In Alberta, the distribution of people is largely determined by vegetation type and geography, which also acts as a barrier from invading rats. The province is protected from rat invasion in the south by open, relatively unsettled short-grass prairie, in the north by boreal mixed-wood forest, and in the west by the Rocky Mountains. The only route of invasion is overland from the east along a sparsely populated rural area, itself a limiting factor to rat migration.”

– From Norway Rat Exclusion in Alberta, published as part of the Proceedings of the Eighteenth Vertebrate Pest Conference (1998).

To address this, Alberta has maintained a Rat Control Zone (RCZ) along the eastern border with Saskatchewan since the 1950s. This 600-km long by 29-km wide swath of land runs from Cold Lake in the north to the Montana border in the south (Figure 1). Supported by government through funding and supplies, the 7 municipalities in the zone bear the most responsibility for rat control. In addition, farmers, counties, pest control officers and the government’s rat control staff help maintain Alberta’s rat-free status.

As well, the Saskatchewan Association of Rural Municipalities operates a provincial rat control program. The governments of Saskatchewan and Alberta collaborate by sharing information and resources. Some municipal employees from Alberta have worked on rat control in Saskatchewan to reduce rat migration into Alberta.

Figure 1. Rat Control Zone in eastern Alberta

View larger image: Alberta Rat Control Zone

Identification

Hundreds of suspected rat infestations are reported each year by concerned citizens. But most sightings turn out to be muskrats, pocket gophers, ground squirrels, bushy-tailed wood rats or mice. However, local or provincial field staff investigate all suspected infestations.

The Norway rat has many distinguishing characteristics and clues. However, some other rodents can be mistaken for rats. Find out how to identify rats, and animals mistaken for rats.

Life cycle

The Norway rat is a shy and primarily nocturnal animal. A rat shelter can be almost any object rats can crawl under, including planks, plywood, buildings or structures resting on the ground.

Once secure, rats will quickly seek food. A Norway rat can survive on a wide range of food items from domestic garbage, rotten meat and fish, stale grain, greenfeed and straw, to fresh fruits and vegetables, packaged foods, sugar and candies.

Following about a 3-week gestation period, 12 to 18 rats are born to a female rat that can be as young as 8 weeks of age. A Norway rat can produce up to 12 litters per year. Male rats are sexually mature at approximately 90 days of age. Norway rats may live up to 18 months in the wild. It has been estimated that, under ideal conditions, a single pair of Norway rats could produce 15,000 offspring in a year.

Prevention

Rats are known to hitchhike; of the 26 rats found in 2020, many rode into Alberta on transport trucks or personal vehicles.

Property owners and tenants can take these basic preventive measures to help stop Norway rats from establishing populations in the province:

Remove food sources – Remove all food items from your property. Because rats can eat almost anything, it is important to remove all food items such as garbage, empty food containers, spilled grain or feed.

Remove rat shelters – Keep your property clean and tidy. Rats will make any object their home as long as they can crawl underneath it. Until a rat can seek out permanent cover, it will use any flat object lying on the ground including tires, planks, square bales, etc. Keep your property clean and tidy.

Rat proof structures – By elevating farm outbuildings, protecting doorways and windows, utility connections and other openings to barns, sheds, granaries, warehouses and industrial structures, rats can be successfully turned away from potential shelter. Efficient rotation of stored grain or forage bales will also discourage rat activity.

Check your vehicle – When you return from an out-of-province trip, check for rats hitchhiking in your vehicle’s undercarriage.

Rats within bale stacks of hay and straw are a continual problem, so farmers are encouraged to place bait within the lower one or 2 layers of bales when the stacks are built. Pits are dug for municipal garbage disposal sites so that garbage can be buried or burned, and sites are fenced to channel garbage into the pits.

Control

The 7 rural Alberta municipalities bordering Saskatchewan carry the major responsibility for rat control. The Alberta government contributes by paying the salary and expenses of a pest control inspector for each municipality along the eastern border.

Small infestations are occasionally found in Alberta and are dealt with through the program’s response plan. When found, rats are isolated and eradicated as soon as possible. Buildings are occasionally moved or torn down. In some cases, rats are dug out.

All reported rat sightings are investigated to verify identification, establish control measures, and determine the possible source.

Table 1. Rat (and non-rat) sightings in Alberta

The public information and education effort supports rat prevention and control. Within the control zone, periodic inspections serve as a reminder that the Rat Control Program is active and necessary. Within Alberta's interior, most residents know that Alberta is rat-free and there is a program to keep it that way.

All Albertans should report suspected rat sightings to the Rat Control Program. Email information about the sighting, including the location and a photo (if safe to do so), to [email protected]. Or contact your local or municipal authorities for further action.

Resources

• Rat Control in Alberta (fact sheet)
• Alberta Invasive Species Council
• Norway Rat (fact sheet)
• Rat Control Program (Saskatchewan Association of Rural Municipalities)
• Rat Control in Saskatchewan (fact sheet)