Moles drive gardeners crazy but do good too

Last Updated: 
August 28, 2008

CORVALLIS - Do you have soft volcanoes of dirt in your yard? Chances are, you may have moles, creatures adapted totally to life underground. Autumn or early winter is a good time to control moles, if they are a problem.

But think twice before you decide to get rid of them because moles play a beneficial role in the environment. They aerate and mix the soil and feed on insects, insect larvae and other invertebrates.

Oregon has four species of moles, according to Oregon State University wildlife biologist Dan Edge: Townsend's, broad-footed, coast, and the shrew mole. All dine primarily on insects and their relatives, rounded out with an occasional botanical treat - including plants and bulbs from the home garden.

Moles are insectivores, not rodents. They have rounded or cylindrical bodies, noses that are pig-like snouts, and short, bare or sparsely haired tails.

With outwardly turned palms and strong nails, moles are equipped for efficient digging. Their tiny eyes are well-concealed in short, dark, velvety fur. They have no external ears.

Moles are rarely seen above ground. It is their mounds of loose soil pushed to the surface that indicate their presence. Active throughout the year, they continually excavate new tunnel systems or extend old ones.

Home gardeners and farmers find moles to often be a major nuisance because of their mounds and their vegetarian snacks. Mole mounds make ideal seedbeds for undesirable grasses and weeds. Mole excavations can expose shallow-rooted shrubs to drying and to insect pests.

Moles will sometimes eat or damage tulips, lilies, iris, carrots, potatoes, peas, beans, corn, oats, wheat and many other plants.

Many home gardeners are confused about how to tell the difference between mole and gopher mounds. And being able to identify the critters is the most important first step in controlling them.

Mole mounds are rounded and symmetrical.

"Moles dispose excess soil by digging a short lateral tunnel to the surface and shoving the soil out on top of the ground," said Edge. "The mounds are built up, volcano fashion, by repeated 'eruptions' of soil pushed up through the center of the pile.

"Pocket gophers, on the other hand, push soil out to the side, resulting in a flattened semi-circle or fan-shaped mound, with their plugged exit hole at one side of the pile," he said.

To learn more about these tunneling insectivores, download or send for the OSU Extension Service publication "Controlling Moles," (EC 987). On the web, go to: Controlling Moles (EC 987).

Printed copies are available by mail by sending a request and a check or money order payable to OSU for $1 per copy plus $3 shipping and handling from: Publications Orders, Extension and Station Communications, OSU, 422 Kerr Administration Building, Corvallis, OR 97331-2119.

Author: Carol Savonen
Source: Dan Edge