Monitoring Vole Activity

Signs of Vole Activity

It is important to be alert for signs of vole damage. If vole activity is detected, the nature of the damage will reveal the type of vole present. As discussed earlier, this information is essential in selecting a control strategy.

Integrated Pest Management for Voles

Sound principles of integrated pest management (IPM) require that pest populations be monitored before any control measures are taken. Grounds managers with shrub and flower plantings can use the apple sign test to determine if voles are present. Control measures can then be restricted to those locations.

Developed in Virginia, the apple sign test has been verified at the Mountain Horticulture Crops Research and Extension Center at Fletcher, North Carolina. This test for voles is inexpensive and does not require much time once the monitoring stations are established.

The Apple Sign Test

The apple sign test was developed to monitor vole populations in commercial orchards. The test permits the grower to detect vole populations before damage becomes severe. It also encourage economy and reduces exposing nontarget animals to control activities. Because the test shows where control is needed, areas without voles are not treated, saving time, money and environmental risk. For these reasons, anyone who has invested in ornamental landscaping or a home orchard should establish and maintain an apple sign test.

The apple sign test is easy to do. The original method used 1-foot-square pieces of asphalt shingles, placed throughout the orchard and particularly where old fields, woods, and shrubs joined the orchard boundary. Brown shingles that will blend in with mulch and leaves or sections of 1- to 2-inch-thick pieces of board painted to match the background color of their flower garden or plantings can be used.

Step 1. Prepare enough of these shingles or wooden pieces to scatter them strategically along the edges and throughout plantings at 15-foot intervals. Sketch a map of the grounds, especially if you have extensive plantings.

Step 2. To establish a test site, place a shingle on the ground, if possible over a hole caused by a vole. If you are monitoring for meadow voles, the shingle must be rounded in a tent-like fashion or propped up 3 to 4 inches off the ground so that the animal can go under it. Mark the location of the shingles on the map drawn in step 1.

Step 3. After 5 days, place a 1/2-inch cube of apple under each shingle. After 24 hours, check whether or not the apple has been removed or eaten. On the map prepared in step 1, mark a simple + (to indicate that voles are present) or - (to indicate that voles are not present). Leave the shingles in place for future monitoring.

Step 4. When monitoring has been completed, you can determine the locations where vole damage may occur and can direct control activities to those areas rather than treating the entire planting.

Step 5. File the recording sheets with the dates of monitoring and the locations at which control measures have been used.

Step 6. Conduct the apple sign test in the fall and spring each year and 21 to 30 days after each rodenticide application.

Trapping for Positive Identification

Trapping is an effective way to determine if one or both kinds of voles are present. A snap-type mouse trap works well, using a small piece of apple as bait. The trap should be placed under a shingle. To trap pine voles, some excavation will be needed to place the trap down in the run. Place the trap at a right angle to the run. Bend the shingle to form an arched roof over the trap so that the spring will clear the shingle. Meadow voles can be caught by setting traps at right angles to their runways in the grass. No excavation is necessary because meadow voles live above ground. Under North Carolina law, a depredation permit must be obtained from an agent of the North Carolina Wildlife Resources Commission before trapping voles.

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