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Non-Aquatic Rodent Damage

Chipmunks & Squirrels
Mountain Beavers
Pocket Gophers
Porcupines
Prairie Dogs
Rats & Mice
Voles
Woodchucks
Links to Further Information

Chipmunks & Squirrels

There are 2 types of squirrels that are nuisance problems. Ground squirrels, as their name implies, dig burrows in the ground. They feed on crops and their burrowing weakens roads, levees, earthen dams etc. Additionally, burrow entrances can cause falls by humans and animals. Ground squirrels also deplete forage for livestock. Tree squirrels feed on tree branch tips, eat evergreen cones (affecting natural regeneration), and strip tree bark to feed on the softer inner sapwood. Orchards can sustain extensive damage. Chipmunks are primarily a minor nuisance, and like tree squirrels, will dig up and eat garden bulbs, and seedlings, as well as forage on bird seed at home feeders.

Mountain Beavers

Mountain beavers are not true beavers and are only found in the United States in the Pacific Northwest. They will eat almost any plant material including bark and small twigs. Mountain beavers cut tree seedlings, girdle stems, damage roots, and climb shrubs and small trees to cut off limbs and twigs. The beavers, in fact, cause considerable damage to Douglas fir regeneration in parts of the Pacific Northwest. They also will raid agricultural crops and occasionally tunnel in the walls of drainage ditches.

Pocket Gophers

Pocket gophers are burrowing rodents that live almost entirely underground. They damage trees by root pruning, stem girdling and clipping. They are responsible for the destruction of underground cables and irrigation pipes. Gophers forage on alfalfa fields and native grasslands, reducing productivity.

Porcupines

Porcupines gnaw bark from the stems of trees and cause girdling on boles. They can damage fruits, sweet corn alfalfa and small grain crops when foraging.

Prairie Dogs

Prairie dogs feed on same grasses and forbs livestock feed on. Their burrowing may destroy other above-ground vegetation, increase soil erosion, and threaten livestock, horses with riders, machinery etc. These rodents are known carriers of plague.

Rats & Mice

Rats and mice are probably the best known and most ubiquitous rodent species. Many rats and mice are "commensal," that is-they live in close proximity to humans. House mice and white-footed mice, like Norway rats and roof rats (black rats), are commonly found around homes, food storage facilities and other structures. Norway rats are also found in sewers. Rats and mice cause structural damage to buildings by burrowing and gnawing on electrical wires, cables, water pipes, insulation and other materials.

Deer mice are the most important seed predators in the northwestern United States in seeding operations for reforestation. The animals are also a reservoir for the hantavirus.

Rats, especially, are known to cause significant losses in nut crops, and citrus and avocado orchards. Additionally, cotton rats forage in alfalfa, grains, grasses, vegetables, peanuts, fruit crops, sweet potatoes, sugar beets. They are extremely troublesome in sugarcane and melons. Polynesian rats also cause significant losses in sugarcane in Hawaii. Kangaroo rats harm revegetation efforts on rangelands and damage irrigated fields and pastures by digging up newly planted seeds and clipping-off new sprouts at the base. Woodrats debark citrus and other trees and are nuisances around cabins, outbuildings and other structures.

Voles

Voles are similar in appearance to mice. They are known to girdle or debark mature trees and clip terminal and lateral shoots of small trees or seedlings, stunting growth or killing the trees. Voles also cause losses in field crops and build extensive runways and tunnel systems that interfere with crop irrigation by displacing water. These runways also ruin lawns, golf courses and ground covers.

Woodchucks

Woodchucks (groundhogs) dig burrows in hayfields and gardens. They feed in gardens, alfalfa, and clover fields, and will consume garden vegetables such as cabbage, beans and peas. They occasionally damage young trees in nurseries by clawing at the base. Woodchucks can gnaw on power cables. The mounds of dirt and holes at burrow openings can be hazards.