Richardson Ground Squirrels (Gophers)
Richardson Ground Squirrels (RGS), locally referred to as Gophers, are a naturally occurring rodent species in Kneehill County and play an important ecological role as a food source for many predators. When populations expand and disperse rapidly, they can pose a significant economic threat to agriculture, as well as severely impact natural ecosystems. For this reason, Agriculture Services recommends developing an understanding of RGS biology and utilizing an Integrated Pest Management (IMP) approach to maintaining gopher populations below threshold limits. A combination of population monitoring and cultural prevention in addition to lethal control measures are commonly recommended strategies for effective control.
Richardson Ground Squirrels first appear in early spring, with the males coming out of hibernation from the end of February to early March, depending on the weather. Two weeks later, the females come up for a short 10-day mating season. After a 23-day gestation period, the litters are born underground and remain there for the first month of their life. Because of their annual life cycle and foraging habits, control measures such as baiting or hunting are best taken in the early spring when both males and females have emerged, before the litters are born.
The first step in the IPM process is determining what your population threshold limits are and monitoring the population. Do regular checks of your fields for mounds and burrows and keep track of the number and density of holes. Count the active mounds within a 1-meter space as you walk 100 meters. Typically, one mound per 2 strides is considered a heavy population. Your threshold can also be based on the economic threshold of crop or forage loss occurring.
The most important step in an IPM program is prevention. RGS’s prefer short vegetation where they can see their surroundings. Maintaining pasture health and implementing rotational grazing can encourage enough ground cover from grasses to discourage populations from moving in and causing more vegetation loss. For cropland, leave headland grasses tall to provide an uninhabited border and encourage predator species such as foxes and coyotes. Raptor (carnivorous bird) platforms, nesting boxes, and perches can also encourage natural predation.
When the population hits a high threshold level, it’s time to move to the final IPM step, lethal control. These measures are temporary at best, and once the population is reduced, additional measures such as cultural control and prevention as described above should be taken to prevent the population from rising again. Lethal control measures can vary in intensity, risk, and effectiveness, so it is best to consider all of the available options and choose what suits your situation best.
- Shooting- Often considered a recreational sport, this method can be effective when used early in the season. Landowners can give permission to any person they wish to enter their property and hunt gophers year-round--as long as they are following all firearm regulations.
- 2% Liquid Strychnine- This concentrate product is designed to be mixed with grain--oats or barley work best--and placed far down the hole before covering. Formerly sold through municipal ASB offices, it is no longer available for purchase as of March 2022 due to deregulation of the product by the PMRA. The federal registration of this product for producer use expires March 2023 and must be used before then. Read and follow the label directions when utilizing this product.
- Chlorophacinone (Rozol, Ground Force)- An anticoagulant, this is usually sold as a ready-to-apply bait through farm supply stores. It can be used downhole or in bait stations and requires multiple feedings to consume a lethal dose. It is not recommended for crop stands with a high percentage of alfalfa as the alfalfa contains Vitamin K which is an antidote for Chlorophacinone.
- Sulphur Gas Cartridges (Giant Destroyers)- As they require gopher holes to be sealed to contain the gas, these types work best for Pocket Gophers (sometimes called moles) but can be used for Richardson Ground Squirrels. Late evening is the best time of day for burrow fumigation when rodents will be sure to be inside.
- Trapping- This option is very labour intensive and likely only suitable for small infestations. Many different styles and brands of traps exist, contact your local farm supply store to see what they have available.
- There are some other products registered for use on Richardson Ground Squirrels including Rocon (mustard foam), zinc phosphide, and phostoxin, though these require special equipment and/or certification for use. If you would like more information on these contact Ag Services.
For more information on the biology and control of Richardson Ground Squirrels check out this informational factsheet from Alberta Agriculture.