Richardson Ground Squirrels (Urocitellus richardsonii)
Richardson’s Ground Squirrels (commonly called gophers or flicker tails) are the most common rodent pests in prairie crops. RGS cause damage through feeding, trampling and the construction of burrows that can damage equipment and injure livestock. As a native pest Richardson Ground Squirrels are an important part of the ecosystem as food source for predatory mammals and birds. These natural enemies along with disease and starvation can keep RGS levels in check but severe infestations will require active management to limit damage and loss of crop.
Richardson’s Ground Squirrels are considered Nuisance species under the Alberta Agricultural Pests Act. The Nuisance designation gives landowners the right to control RGS on their own property but does not require landowners to control RGS.
As with any pest the best management tool to keep Richardson Ground Squirrel populations below damage causing levels is by using an Integrated Pest Management program combining Cultural, Mechanical, Behavioural and Chemical control methods.
The Pest Management Regulatory Agency has de-registered the use of 2% Liquid Strychnine for the control of Richardson Ground Squirrels as of March 4, 2023. Other chemical options exist but agricultural producers should employ other IPM techniques in their ground squirrel management programs.
Non-Chemical Control
Shooting
- Time and Labour intensive
- Firearms laws must be followed
Trapping
- Time and labour intensive
- Not practical for large areas
Cultivation
- Cultivation and/or anhydrous ammonia application destroys burrows, reducing ground squirrel numbers and discouraging reinfestations of old burrows.
Natural Predators
- Leave standing trees or construct artificial pole nesting sites for hawks (a pair of nesting hawks can consume over 500 ground squirrels in a season).
- Long grass on field edges discourages ground squirrel infestations and increases the hunting success of foxes and coyotes.
Chemical Control
Current options for chemical control of Richardson Ground Squirrels are available in the from of pre-treated grain and paraffinized baits. Baiting is most effective early in the season, before vegetation greens up. Once there is ample supply of fresh vegetation RGS are less likely to consume bait. Pre-baiting with non-treated grain for a few days before application can increase consumption of bait. Landowners using bait must take precautions to reduce the likelihood hood of unintended poisoning to children, pets, livestock and wildlife and secondary poisoning of scavengers and predators consuming ground squirrel carcasses. Bait stations must be secured and tamper proof and treated fields must be checked daily with any carcasses removed and properly disposed of.
Click here to view an Inverted T Bait Station
Always read and follow the label directions before using any pesticide.
Anti-coagulant baits: Chlorophacinone (Rozol), Diphacinone (Ramik Green)
- Requires multiple feedings, a steady supply of bait must be maintained for at least 5 days
- Can be used in bait stations and burrows
- Risk of secondary poisoning to predators and scavengers, treated areas must be checked and carcasses removed
- Vitamin K is an antidote, but will not provide control in alfalfa fields
Acute poison baits: Zinc Phosphide (Burrow Oat Bait, ZP Rodent Bait AG)
- Single feeding bait
- Reduced risk of secondary poisoning
- Can be used in bait stations and in burrows
- Moisture limits efficacy, should not be applied to burrows when soil moisture is high
Fumigants: Aluminum Phosphide (Phostoxin)
- High risk to applicator and bystanders
- Restricted use pesticide, must have Farmers Pesticide Certificate with Exterior Rodent Control endorsement
- Soil moisture must be high enough to cause reaction of fumigant pellets
- Burrow entrances must be filled in
Non-poison control methods: Carbon Monoxide (Cheetah machine) and Rocon Rodenticide Foam
- Requires specialized equipment
- Labour/ time intensive
- Not practical for large areas
- Suitable for use in areas toxicants are not permitted
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