Species

Gophers are burrowing rodents in the family Geomyidae. Two species of pocket gophers have appeared in Washington. The Northern pocket gopher (Thomomys talpoides) occupies much of eastern Washington. The Mazama or Western pocket gopher (Thomomys mazama) is the predominant species in the western part of the state.

Gophers are often mistaken for moles because both are burrowing rodents. Gophers are also similar in appearance to squirrels

Host/Site

Gophers burrow through soil and feed on plant roots, seeds, and bulbs. They are especially active near the soil surface during spring and fal. Gophers consume about 60% of their body weight each day. They can also feed on plants found near the entrances to their tunnels, and can uproot and pull entire plants into their tunnels.

Gophers can be beneficial to soil quality, but can significantly damage plants and produce large soil mounds from burrowing, which many view as unattractive.

Identification

Indicators
Gopher mounds can be similar to mole hills but there are some distinct differences. Their mounds are fan-shaped, unlike mole hills which are circular with an often undetectable plug at the center.

You can locate a gopher burrow by first finding the mound. After locating it, look for a depression in the land around the mound. This will help in locating the plug. Then begin probing the ground for the burrow with a stick or wire about 10 inches from the plug. If you poke through ground that is hollowed out a few inches (the probe will drop a short distance) you have found the tunnel.

Life Cycle

Gophers do not hibernate but spend most of the time underground, coming out only to look for food, search for new areas to burrow, and look for mates. They live in solitude except when mating or raising young. Mating occurs sometime between January and April. Lifespans can reach 12 years.

Natural Enemies

Gophers spend much of their time underground, protected from other omnivorous animals. Many animals will prey on gophers when given the chance, including dogs, cats, raccoons, weasels, foxes, badgers, coyotes, and hawks. In more rural areas, snakes and owls are the dominant predators.

Monitoring

Monitor your yard and garden for gopher mounds and tunnels. Look for the fan shape mound that is a signature of gophers. Use a stick or probe as described earlier to penetrate the soil on the side of the mound opposite the fan. If you feel your probe descend 2-3 feet into the soil then you have gophers.

Action Threshold

Gophers provide benefits to soil but can indeed be detrimental when they destroy plants. Gophers tunnel through soil and create burrows below ground, which are filled up with vegetation and redistributed soil. The newly compacted soil benefits from the increase vegetative content in it, and the soil quality increases. Additionally, the mounds of fresh soil created at the surface create a fresh soil seedbed for new plants, which can increase plant variety at the site. Gophers can become pests when they inhabit areas where plants are being cultivated.

In small numbers, gophers might not be a big problem, and should be considered a natural player. However, an increase in gopher holes in your yard plus having your plants destroyed will be the sign to take action.

Physical/Mechanical Controls

There are a few ways to directly disrupt gophers and their burrows. Installing barriers such as fences deep enough (5-6 feet to be safe) in the ground can prevent gophers from tunneling. A barrier around your garden or orchard can also protect the plants themselves from being pulled out and consumed by gophers.

Flooding burrows can be complicated if the burrow is located next to a building. If the burrow is far enough away from any structures, you can insert a hose into the burrow. Gophers will escape from the mounds,

Setting traps in the gopher burrows can effectively trap the animals. Gopher Getter or Macabee traps can be purchased and inserted into the burrow. It is recommended to stake down the traps by tying them to a secure rope or twine in order to retrieve the traps afterward and to prevent the rodents from pulling the traps down into the burrow. Handle the traps with care and wear gloves when setting them up to avoid having human scent being passed onto them.

The use of frightening or disturbing devices, such as vibrating stakes or ultrasonic devices may work, but experiments have been met with mixed results. This could be due to gophers becoming accustomed to the devices and not being bothered or frightened anymore.

Biological Controls

Introducing gopher predators into your garden or yard would probably bring more nuisance than benefit. However, in a rural and open environment, a gopher problem might be eliminated by placing barn owl boxes around a property to encouraging owls, for example, to nest in the vicinity.

Chemical Controls

The most common chemical controls to combat gophers are strychnine-based. These substances are very toxic to gophers, predators that eat poisoned gophers, and to humans. These treatments are therefore not recommended. Anticoagulants such as warfarin are less toxic on non-target organisms, but are still dangerous, and not suggested for use.

References

"Pests: The Vermin Reports- Gophers." 2002. University of Washington Extension. 22 Aug 2008. <http://wihort.uwex.edu/pests/Gophers.htm>.

Link, Russell. Living with Wildlife in the Pacific Northwest. Seattle: University of Washington Press, 2007. 15 Oct 2008.
< http://wdfw.wa.gov/wlm/living/gophers.htm>.