Richardson's Ground Squirrels

Richardson's Ground Squirrels as Pests

The two main complaints about Richardson's ground squirrels (also known as gophers) are their tunneling behaviour and their foraging behaviour. Despite many anecdotal reports on the impacts of Richardson's ground squirrels on agricultural crops, scientific studies that accurately measure these impacts are rare. Governments are increasingly realizing that accurate information is required to enable landowners to assess when and how much time and effort to spend on control measures.

Many ranchers and farmers have adopted a zero-tolerance attitude towards Richardson's ground squirrels and seek their total elimination. This attitude dates back to settlement days when prairie was newly broken, agricultural practices were not yet suited to prairie conditions, and any further loss of yield was unacceptable. Given the time, cost, and effort of attempting to control a native species, more information is needed on the real impact of ground squirrels to ensure that farmers and ranchers are spending their resources wisely if they choose to undertake control measures.

Although many people view Richardson's ground squirrels negatively, others work to promote healthy populations of Richardson's ground squirrels. Ground squirrels play several critical roles in the prairie ecosystem; for example, they are a food source for many predators and they create nesting habitat for burrowing owls.

Physical methods such as shooting and trapping and chemical methods such as poisons, fumigants, and reproductive sterilants have been used with variable success. Although distribution of poisoned grain can result in the immediate death of the majority of the population and chemosterilants can suppress reproduction for one season, numbers quickly rise again because ground squirrels from neighboring communities take over vacant burrow systems. Unless existing burrow systems are destroyed, reinvasion is inevitable.

Controlling Richardson's ground squirrels in lawns and gardens

laying sod over chicken wire
In this farmyard, Richardson's ground squirrels had invaded the lawn and created numerous tunnel systems over a 7-year period. In 2005 the owners humanely killed the resident squirrels, removed the old sod, tilled the soil, plugged remaining old tunnels with expanding foam, laid down chicken wire, then installed new sod. Twelve years later no reinvasion had occurred.

Once Richardson's ground squirrels have established burrow systems, controlling them becomes difficult because removal of animals results in vacant burrows that are eventually re-occupied by other squirrels. If an area is already inhabited by ground squirrels, those animals first have to be removed humanely. Richardson's ground squirrels do feel pain, so only humane methods are acceptable for actually capturing and killing the animals. After humane removal of animals, the area should be tilled as deep as possible to destroy existing tunnels and entrances.  Chambers used for sleeping and hibernation are usually located at depths of 35-80 cm, so it may be impractical to till deeply enough to destroy the entire burrow system.  Instead, block off access to deeper portions of the system by filling tunnels with expanding foam.

Before planting the new lawn or garden, spread chicken-wire on the ground to prevent the excavation of new tunnels and to reduce the likelihood of nearby animals discovering the deeper remnants of the old burrow systems.  Immediately cover the wire with sod or top soil. If ground squirrels start to invade, take immediate action to make new holes unattractive by filling them with expanding foam, covering with gravel and rocks, or pouring in unpleasant smelling liquids. Ground squirrels can be very persistent at trying to get back into a hole, so often these steps need to be repeated over a week or more until the animal gives up.

Richardson's ground squirrels feel pain; only humane methods are acceptable for capturing and killing the animals.

Related Pages:
Burrow System
Diet

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