Get to Know Your Grasslands: Richardson Ground Squirrels

The native prairies serve as a habitat for many diverse wildlife, all unique with their adaptations. While some are endangered rare species, others are considered nuisances. Producers across Canada can typically agree that Richardson Ground Squirrels or gophers, are unwanted in their pastures and fall into the nuisance category.

Richardson Ground Squirrels are abundantly found across the prairies. They are herbivores and will each almost any plant including forage grasses, legumes, cereal crops, pulse crops and native grasses. Each ground squirrel burrows a home underground, with only its closest family members allowed in that burrow. Their preferred environment is open terrain with lots of visibility to let them spot potential predators. A female gopher’s summer home consists of approximately 240 square meters and its borders overlap with its neighbours. The average burrow system has 2-3 exits and 2-5 sleeping spots. However, the home range is not a permanent spot and fluctuates based on a variety of factors including weather, mating season, hibernation, predators, and ground conditions.

Richardson ground squirrels inhabit above ground between end of February until October, being most active during the summer season. Adult males typically emerge from the ground in February, while females wait until March. They both become reproductively mature at a year old. Mating occurs after hibernation in March, as a female gopher is only in heat for 4 hours of the year. Once mated, a Richardson ground squirrel’s gestation is approximately 23 days. The average little size is 5-8 pups, with only one litter being born a year per female. Juvenile squirrels emerge out of the burrow at four weeks old and stay with their mom until then. The survival rate for juvenile Richardson ground squirrels is 10-20% for males and 40-50% for females. The life span is three years for males and six for females. However, that life span depends directly on the quality of life. Predators also impact this lifespan, as the Richardson ground squirrel has a variety of threats including foxes, hawks, badgers, weasels, and coyotes.

With gophers’ limited breeding time, low survival rate, and short life cycle, their abundant presence in the prairies is confounding and inconvenient to landowners. Producers often attempt to control population by trapping, shooting, and toxic baits. When we are managing native grasslands, we expect to see some populations of gophers but if it reaches a point where the population seems excessive and they are over taking areas of rangeland, we can also look at management changes.

Since gophers prefer areas of short vegetation to see predators, they are attracted to areas that may have been over grazed or high traffic spots. By assessing the amount of bare ground to determine if it’s abnormally high for that area then we discuss grazing management changes to prevent this from happening to other areas. Keeping pasture height above 15 cm if possible has been found to reduce gopher population as it reduces visibility to see predators. Rotating areas of heavier concentration such as salt and mineral placement can reduce the likelihood of gopher infestations by spreading out these locations.

The use of rodenticides is a common practice to eliminate the presence of Richardson ground squirrels. It is best to do it before Spring, as it greens up and the hibernating gophers are lacking food sources and will often eat whatever is in front of them. Before the gophers and youth emerge from their burrowing holes is the ideal time to ensure optimum success.

It’s important to remember that using rodenticide bait can also affect other animals in the food chain such as coyotes, owls, hawks, eagles and anything else that would prey on them. The native rangelands are home to numerous grassland birds at risk and given the declining populations, avoidance of poisoning should be adhered to at all costs. Another tactic to target gopher populations is installing nesting poles for hawks in pastures. These allow a suitable area for hawks to build a nest where there are no natural structures existing such as out in pastures with no trees. For example, Ferruginous hawks will eat an estimated amount of 500 ground squirrels every year but they are incredibly particular with nest location and prefer areas away from human development. Building these nesting platforms can be quite simple and once a nest is built many hawks and eagles will continue to revisit that site regularly.

Badgers are also known to follow gopher populations and will deplete colonies of over 50% in a summer before moving onto the next colony. They have also been known to co-hunt with coyotes which further increases their success between the below ground and above ground predator. So next time you curse a badger on your pastures, think of the effect they can have in eliminating gopher populations.

Gophers can be a problem for many ranchers across Saskatchewan, now that you understand their behavioural a little more, it may help you to win your gopher battle next year.

 

References:

 https://www.saskatchewan.ca/business/agriculture-natural-resources-and-industry/agribusiness-farmers-and-ranchers/livestock/pastures-grazing-hay-silage/control-of-richardson-ground-squirrel
https://escholarship.org/uc/item/6zj2p2x1
https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/1939350

 

Author:

Jorja Beck and Mindy Anderson