Alberta’s rat-free status creates one problem – if you’ve never seen one, you won’t necessarily recognize the signs that they’re around.
Advising Albertans of those telltale signs is one the jobs of Rob Pulyk of the regulatory services division of Alberta Agriculture in Vermilion. He described his experiences with rat control at the Grazing School for Women here in early June.
Norway rats are a nuisance in every province except Alberta, where they are legislated as a pest under the Pest and Nuisance Control Regulations. The difference between pests and nuisances is that the government is free to intervene in quarantine or eliminating pests, explained Pulyk.
The Norway Rat originated in Europe and eventually infiltrated Canada. Alberta developed its rat control program in the 1950s and is still the only province that enforces control. Borders between Saskatchewan and Alberta are controlled so that rats do not enter the province of Alberta. Border areas are patrolled by government personnel known as the “Rat Patrol.”
The area patrolled is 15 miles wide and 380 miles long and includes the municipalities of Bonnyville, Wainwright and Vermilion. “We provide the municipalities with specific types of bait to catch rats,” said Pulyk. “This year’s a good year for water bait because there is very little water around the province right now so the rats will go for the water bait.”
The poisons in the baits thins out the rats’ blood, forcing them to wander in a daze for several hours before they die.
Many of the animals walk over the border from Saskatchewan or hitch rides on trains, trucks or other vehicles. “If you go to Saskatchewan and come back, check your vehicle,” said Pulyk.
Rats will often create holes in spaces where hay or straw bales meet, said Pulyk. They tend to make a number of curved holes in close proximity to each other to use as escape hatches. Rat feces near the holes can also be a sign of rat activity. The animals will clean out their burrow by shoving their scat out the door, effectively revealing their presence. The feces of a rat are capsule shaped and are about three quarters of an inch long.
Rats will also create tunnels and runs about two inches wide and about two inches apart from each other. The animals like to camouflage their holes by putting grass or straw over their escape holes to cover them. Unlike gophers, rats do not seem to leave piles of dirt around their escape holes. The animals will also attempt to create dens by digging around the bottom of structures or buildings. They have been known to create burrow systems in the grass and are capable of boring through a variety of materials as they need to constantly chew things to file down their sharp teeth. The animals can eat the inside of a circular bale of hay and can chew a bale to bits.
Rats will often eat the grass in their runs, wear down a path, and will move onto another area once they have exhausted all the potential food from one spot. The animals can breed quickly as rats are sexually mature two months after they are born.
Norway Rats are nocturnal and generally will not be seen doing the daytime. The evidence of rat activity during the day can be a sign that the infestation has grown to a sizeable proportion, said Pulyk. “We encourage all landowners to keep their yards clean, to not leave anything piled up, and to make sure the grass is cut short, and to be on the look out for the animals,” he said.
When an infestation occurs, in a series of bales, for instance, the regulatory services staff will take a number of steps to eliminate the animals.
“The poisons we put out will start minimizing the population so that when we start moving the bales, we’re dealing with fewer numbers,” said Pulyk.
Animals could also be killed with guns if necessary. Bales inhabited by rats often need to be destroyed since rats carry a virus which could make cattle abort.
Related species like mountain rats, roof rats and muskrats still exist in Alberta and are not on the pest list.