Managing Wyoming Ground Squirrels Fact Sheet No
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Managing Wyoming Ground Squirrels Fact Sheet No. 6.505 Natural Resources Series|Wildlife by W.F. Andelt, S.N. Hopper* Revised 3/16** Quick Facts The Wyoming ground squirrel (Urocitellus the north central and northwestern sections • The Wyoming ground elegans formerly Spermophilus elegans) is of Colorado. It prefers open sagebrush, squirrel is one of six species one of six species of ground squirrels found grasslands and subalpine meadows. This in Colorado. Formerly called “Richardson’s has garnered them the nickname of “high of ground squirrels found in ground squirrel,” the Wyoming ground mountain prairie dogs,” because they can Colorado. squirrel averages 10 to 15 inches long and tolerate high elevations and will flourish if • Wyoming ground squirrels weighs 9 to 14 ounces as an adult. Its fur predators are absent. compete with livestock for is generally a brownish smoke-gray, with forage and can destroy food a dappled pattern of cinnamon-buff. The crops. underside of the tail is buff. Food Habits and Biology Wyoming ground squirrels prefer green • Wyoming ground squirrel The animals are not nearly as large as foliage, such as grasses, but also eat forbs burrowing can damage prairie dogs but are sometimes mistaken and shrubs. When green vegetation becomes hay fields, grasslands, golf as such. Wyoming ground squirrels have scarce, the squirrels eat dry grasses and seeds. courses, and lawns. an underground burrow without the larger They also eat insects, including grasshoppers, mounds, and most often what one sees is crickets and caterpillars, and eggs from • Wyoming ground squirrels the ground squirrel darting into the hole for ground-nesting birds. can be controlled by safety during the morning hours. shooting, trapping, poison Wyoming ground squirrels construct grain baits and fumigation. Wyoming ground squirrels are found and live in underground burrows. In brushy in Colorado, southern Wyoming, western country, Wyoming ground squirrel burrows Nebraska and Utah. The species occupies often are identified by a substantial pile of areas from 5,000 feet to above timberline in debris (sticks, rocks, sagebrush leaves) that covers the area downslope from the burrow entrance. Squirrels stay in their burrows at night and during the warmest part of summer days. The burrow is the center of a ground squirrel’s activity. The squirrels enter their burrows in late July or early August and hibernate until the following March or April. Males usually come above ground one to three weeks before the females. Breeding takes place one to four days after females emerge from hibernation. Figure 1: Wyoming ground squirrel distribu- The young are born after a three- to four- tion*** week gestation period with two to 10 young *W.F. Andelt, Colorado State University professor emeritus, per litter. Only one litter is produced each fish, wildlife and conservation biology; S.N. Hopper, year. The young are weaned at five weeks and consultant. *Marvin Reynolds, CSU Extension area are foraging above ground by June. Density © Colorado State University director, range & natural resources, SLV Area. 7/2014 of Wyoming ground squirrel populations Revised S. Bokan, Small Acreage Coordinator Boulder Extension. 8/98. Revised 3/16. can range from two squirrels per acre before County; K. Crumbaker, Ag and Natural Resources Agent www.ext.colostate.edu Larimer County; T. Hoelsi, Extension County Director young are born in the spring, to 20 or more Grand County; D. Lester, Extension County Director Park animals per acre in early June when juveniles County and I. Shonle, Extension County Director Gilpin and adults are active. County, 3/16 Management Methods Health Risks Economic Damage Ground squirrels are hosts for fleas Several alternatives are available for High concentrations of Wyoming and may act as carriers for bubonic Wyoming ground squirrel management. ground squirrels can pose a serious plague. Plague is transmitted to Landowners should use multiple methods pest problem. They compete with humans via flea bites. Early symptoms for squirrel management such as habitat livestock for forage and can destroy of plague include swollen and tender modification, predators, exclusion, food crops. The mounds of dirt that trapping and shooting. For the average lymph nodes, chills and fever. Early squirrels excavate to build burrows high mountain homeowner, unfortunately, diagnosis and treatment is imperative. in hay fields can damage haying the remedy is not a quick nor easy one. When walking through suspected The goal is not to eliminate the entire equipment and take fields out of plague areas, apply an insect repellent population, but to keep the population production. Burrowing activity also to socks and pant cuffs before tucking under control. A Wyoming ground can damage grasslands, golf courses pants inside boots. squirrel population of over 8-10 per acre and lawns. is a growing problem for any homeowner that won’t simply take care of itself. When when the food source is no longer plentiful. Ecological Value using rodenticides, always read and If badger encounters persist, contact your Predators of the Wyoming ground follow label instructions and other local local Colorado Parks & Wildlife officer and squirrels include bullsnakes, rattlesnakes, regulations for proper use to minimize or they may be able to help you relocate the coyotes, foxes, badgers, weasels, bobcats eliminate off target harm to children, pets badger. and raptors. and wildlife. Canine & Feline Predators Wildlife Predators Dogs and cats can in fact be very helpful Utilizing natural predators of Wyoming in reducing ground squirrel populations. ground squirrels is an easy management Dog breeds that are quick hunters such as method. Many of the high mountain the Terriers, especially Jack Russells, and areas are home to a variety of hawks, the Australian Shepards are the best breeds foxes, badgers, and coyotes that are natural for decreasing squirrel populations. Cats predators of the squirrels. can be effective if quick and agile enough to catch a scurrying Wyoming ground Unwanted Predators squirrel. In higher mountain areas, homeowners may find themselves with increasing Shooting Figure 2: Wyoming ground squirrel bur- Wyoming ground squirrel populations Small, isolated colonies of Wyoming row has a fanned out low mound. The hole with a “not so friendly” badger. Although ground squirrels can be effectively entrance is at an angle and remains open. badgers can help manage the ground controlled by shooting. Shooting lowers Usually ground squirrel burrows have squirrels, they can also create new the population by removing individuals several entrances. challenges. While most badgers prefer to and disrupting their life cycle. However, if remain out of sight and eat during the dark there are other colonies of ground squirrels night hours, badgers have been known to nearby, individuals from those populations attack people when threatened and with will migrate into the area where squirrels their medium size of 40-55 pounds (mature are being removed. For effective weight) should be considered dangerous management of problem ground squirrels, with their “bad tempers” and fierce claws. a population must be kept under constant If you encounter a badger, vacate the area as shooting pressure. quickly as possible. Unlike other burrowing animals, the Most badgers will burrow a large hole, Wyoming ground squirrel is considered a 8-10” in diameter or more. While they help small game species in Colorado, allowing with the ground squirrel problem, they licensed hunters to harvest them year- create a new problem to horse and large round without a limit. Figure 3: A newly formed Wyoming livestock owners, as these animals can fall ground squirrel mound. Note the fanning into these large holes and injure themselves. Always use good hunter safety practices similar to pocket gopher holes. Wyoming and follow local laws and regulations when ground squirrel holes remain open. Badgers will only be drawn to your using fire arms to depopulate. Don’t shoot property if Wyoming ground squirrels are within ¼ mile of any roadway. Always abundant. The badger will often move on, know your target and beyond. always read and follow the label and controlling large numbers of Wyoming Source of Supplies guidelines and be sure you understand ground squirrels. Baiting is most effective at Rodenticides for controlling them prior to use to minimize off target two points during their annual cycle: early Wyoming ground squirrels are (i.e. raptors, dogs, and cats) poisoning. spring, or late June to early July. available through commercial vendors Rodenticides are meant to kill rodent in Denver, a few farm supply stores species but will also kill other animals if In a year of average rainfall, begin outside Denver, and the Animal Health used improperly. poison grain control early in the spring, Division, Colorado Department of about one to two weeks after squirrels Steps for safe use of rodenticides* Agriculture, (303) 869-9130. Traps can emerge from their burrows. Continue for be purchased or ordered at hardware -Positively identify the pest and one month or until vegetation turns green. stores. determine all techniques that can be used to Early control is enhanced by cold weather deter the pest such as habitat modification and minimal vegetative growth that makes Trapping and exclusion. bait more desirable to ground squirrels. -Decide what your threshold limit For small populations, wire-mesh cage is. Set realistic goals such as minimizing As soon as green vegetation becomes traps can be set anywhere that squirrels rodent numbers. Do not expect to available, bait is less accepted. To achieve frequent. Place traps on level ground within eliminate them completely. successful control in early spring, apply bait a few feet of burrows or other high-activity -Choose the most effective, least toxic when the entire ground squirrel population areas. Bait for several days with the door rodenticide to minimize potential non- is active. If part of the population is still wired open to get squirrels accustomed to target poisoning.