Managing Pocket Gophers Fact Sheet No. 6.515 Natural Resources Series|Wildlife by W.F. Andelt and R.M. Case* The northern pocket gopher usually is The four pocket gopher species found in Quick Facts Colorado are distributed almost entirely in dark-colored with a whitish chin and belly different areas (Figure 1), possibly because whereas the Botta's pocket gopher is often • Four species of pocket of different ecological requirements reddish-brown with a blackish chin and gophers are found in reddish belly. The plains and yellow-faced or competition. Plains pocket gophers Colorado. (Geomys bursarius) are abundant in sandy pocket gopher species are often difficult and silty soils of the plains but are not to tell apart. The plains pocket gopher has • Pocket gophers reduce abundant in compacted soils. The northern two distinct grooves on the front surface productivity of portions pocket gopher (Thomomys talpoides) of each upper incisor where as the yellow- of alfalfa fields and native occurs in upland areas of the eastern faced pocket gopher has one distinct grasslands by 20 to 50 plains to shallow gravel in mountainous groove. percent. areas to thin soils of the alpine tundra. It is the most common species in mountain • Damage by pocket gophers rangelands and aspen forests. Botta's can be reduced by exclusion, (formerly called valley) pocket gopher cultural methods, habitat (Thomomys bottae) is found primarily in well- modification, trapping, and developed soils of warm valleys in southern toxicants applied by hand or Colorado. The yellow-faced pocket gopher with a mechanical device. (Pappogeomys castanops) inhabits a portion of southeastern Colorado where the plains pocket gopher is found. However, the yellow-faced pocket gopher is confined to drier sites. Pocket gophers attain the highest densities on light-textured soils with good herbage production. Shallow Figure 1: Distribution map of Botta’s (Thomomys soils limit pocket gophers due to tunnel bottae) and Plains (Geomys bursarius) pocket cave-ins and poor insulation from warm gophers.1 summer and cold winter temperatures. Distinguishing among the four pocket gopher species in Colorado is moderately easy. The northern and Botta's pocket gophers have smooth upper incisors with a single indistinct groove near the inner border and have smaller bodies and proportionately smaller front feet than the plains and yellow-faced pocket gophers. *W.F. Andelt, Colorado State University Cooperative Extension wildlife specialist and associate professor, fishery and wildlife biology; and R.M. Case, forestry, fisheries and wildlife, University of Nebraska. S. © Colorado State University Bokan, Small Acreage Coordinator, Boulder County, K. Extension. 11/95. Revised 2/16. Crumbaker, Ag and Natural Resources Agent, Larimer Figure 2: Distribution map of Northern www.ext.colostate.edu County, T. Hoesli, Grand County Extension County (Thomomys talpoides) and Yellow-faced Director, D. Lester, Park County Extension County (Pappogeomys castanops) pocket gophers.1 Director, & I. Shonle Gilpin County Extension Director. Reviewed 2/2016 Biology, Reproduction 10 young (typically three to four) after a and Behavior gestation period of about 20 days. Usually, only one adult is found in each burrow Pocket gophers feed on roots they system except during breeding and while encounter from digging, from vegetation raising young. Six to eight plains pocket they pull into the tunnel from above, and gophers per acre are considered high vegetation above ground near the tunnel. densities whereas northern pocket gophers They like above-ground vegetation when occasionally reach densities of 20 per it is green and succulent. Many trees and acre. Young pocket gophers usually begin shrubs are clipped just above ground, dispersing from the natal burrow in June especially under snow cover when about one-third grown. Figure 6: Mound produced by a pocket gopher Pocket gophers construct burrow systems by loosening the soil with their Damage and Control claws and incisors, and then use their forefeet and chest to push the soil out of the Pocket gophers can reduce the burrow. They do not use cheek pouches to productivity of alfalfa fields and native carry soil. The soil is deposited in fan- grasslands on which they are found by 20 shaped mounds 12 to 18 inches wide and 4 to 50 percent. If gophers are present on 10 to 6 inches high. percent of a field, they may reduce overall forage productivity of the field by 2 to 5 Burrow systems consist of a main percent. Gopher mounds dull and plug tunnel, generally 4 to 18 inches below sickle bars when harvesting hay or alfalfa. the soil surface, and a variable number of Gophers sometimes damage trees by lateral burrows extending from the main. girdling or clipping stems and by pruning Figure 7: Fan-shaped mound with closed burrow is typical of pocket gophers Lateral burrows end with a soil mound or roots. Gophers may, at times, destroy soil plug at the surface. Burrows are about underground utility cables and irrigation nonlethal measures such as habitat 2 to 3 1/2 inches in diameter, depending pipes. on the size of the gopher. A burrow system modification, resistant crop varieties, crop may be linear to highly branched, may rotation, flood irrigation, or cultivated contain up to 200 yards of tunnels, and may Gophers are not protected by state or buffer strips which may be as cost effective have a hundred or more mounds. federal laws but they do play an important as lethal measures and should minimize role in ecosystem function. When selecting adverse environmental impacts. a damage-control program, consider Ecological Value Pocket gophers are beneficial in several ways. Their burrowing activities increase soil fertility by adding organic matter Figure 3: Pocket gopher mound and its relation to the tunnel system. in the form of plant materials and feces. Burrows increase soil aeration, water The soil from burrow building forms infiltration, reduce compaction, mixing eskers, long snake-like mounds of soil organic material into subsurface soil layers looking like above-ground soil-filled tubes.. and increase the rate of soil formation Eskers are named due to their similar Figure 4 by bringing up subsoil, subjecting it to appearance to the ridges deposited by weatherization. glacial melt water streams. Figures 4 and 5: Two examples of eskers--these are only seen as the snow melts, and are a result of burrowing activity under the snow. Pocket gophers are prey for owls, hawks, Pocket gopher mounds are built badgers, coyotes, foxes, bobcats, skunks, of excavated soil. The gophers usually weasels, bullsnakes and rattlesnakes. construct one to three mounds per day although the rate varies. One gopher brings about 2 1/4 tons of soil to the surface each year. Mound-building activity usually is greatest in spring and fall. Pocket gophers usually breed in the spring and produce one litter of one to Figure 5 Exclusion Other Pocket gophers can be excluded from Shooting pocket gophers is valuable plots of ornamental trees and impractical because they seldom shrubs with a 1/4 to 1/2-inch mesh wander above ground. hardware cloth fence buried at least 18 inches. The bottom of the fence should be Protect buried utility cables and bent at a 90-degree angle so that a 6-inch irrigation lines by enclosing with apron of wire projects horizontally toward lead, PVC, or other conduit materials the gopher. Place the fence in shallow soil exceeding 2.9 inches in diameter. at least 2 feet from the nearest plants to Pocket gophers can damage cables Figure 8: Trap placement in burrow systems: (A) avoid root injury. This method is of limited Place two traps set in opposite directions in main armored with soft metals (lead, practicality because of expense and labor. tunnel; (B) set single trap in lateral tunnel from aluminum) if the diameters are less Cylindrical plastic Vexar mesh tubes placed which soil plug has been removed. Wire each than 2.9 inches. Crushed rock or trap to a stake. over the entire seedling, including bare gravel greater than 1 inch in diameter root, can reduce damage to newly planted placed around cables may protect for plains pocket gophers because they seedlings. them. easily survive on grasses. In orchards and shelterbelts, forb control will likely limit Ornamental beds and vegetable beds gopher damage. can be protected by lining the beds with Figure 8. The tunnels either can be left 1/4" hardware cloth. The easiest way to do Flood irrigation can effectively control open or covered after setting traps. Check this is to create a raised bed and staple the gophers, especially in fields that are traps twice daily because gophers often hardware cloth to the bottom. However, in- leveled to remove high spots that might visit the traps within a few hours. If a trap ground beds can be dug out to a depth that serve as refuges. The wet-flooded soil is not visited within 48 hours, move it to will accommodate the roots of the plants generally prevents diffusion of gasses in a new location. Trapping usually is most you wish to grow, lined with hardware and out of the burrow and sticks to the successful in the spring and fall when cloth, and then refilled with the soil. It is pocket gopher's fur and claws creating an gophers are actively building tunnels. recommended to put a fence at least one inhospitable environment. foot high, around the beds, to keep the gophers from going over the barrier. Rodenticides Trapping Crop Management Lethal trapping is one of the best Using and handling rodenticides methods to reduce pocket gopher numbers safely on small to moderate-sized fields (less Alfalfa varieties with several large When dealing with any rodent problem, than 50 acres) and to remove remaining roots rather than a single tap root suffer utilize all management techniques to animals after a poison control program.