Ask a Specialist: Dealing with Meadow Vole Damage
Tuesday, Mar. 26, 2013
Extension Wildlife Specialist
Utah State University
Phone: (435) 797-3975
ASK A SPECIALIST: DEALING WITH MEADOW VOLE DAMAGE
LOGAN - As the snow melts this spring, many homeowners are surprised as they walk across their lawns and fields and find extensive surface runway systems and numerous burrow openings. In addition there is girdling or chewing damage to orchards, ornamentals and trees.
According to Terry Messmer, Utah State University Extension wildlife specialist, the damage is most likely caused by meadow voles. Voles are often confused with field mice, but their appearance and habits are much different. Meadow voles are pudgy, mouse-to-rat sized rodents with blunt faces, small eyes, short ears, short legs and a short tail. There are eight species of voles in Utah, and their lawn damage is easy to identify. Excessive surface runways, following weeks of snow cover, are characteristic of meadow vole populations.
“The problem appears to be especially bad this spring since we had so many weeks of deep snow,” Messmer said. “Most damage occurs during the winter as they eat and multiply under the snow. They are active both day and night and don’t hibernate. Voles have one to five litters throughout the year with one to 10 young per litter. The young are weaned by the time they are 21days old, and females mature in 35 to 40 days. Uncontrolled, they multiply quickly and do significant damage. They can live in dense populations along ditch banks, rights-of-way and near unmanaged waterways.”
Tilling the soil is effective in reducing damage as it removes cover, destroys existing runway-burrow systems and kills some voles outright, he said. Because of tillage, annual crops tend to have lower vole populations than perennial crops.
Cultural and habitat modification can also reduce the likelihood and severity of meadow vole damage. Eliminating weeds, ground cover and litter in and around crops, lawns and cultivated areas reduces the capacity of these areas to support rodents. Mowing, spraying and grazing are cost effective ways to control vegetation. Mulch should be cleared 3 feet or more from the bases of trees.
Messmer said hardware cloth cylinders can exclude meadow voles from girdling or feeding on and removing bark from young trees. The mesh should be 1/4 inch or less in size and roughly 12 to 18 inches tall. It is wise to bury the bottom of the wire 6 inches below ground level to keep voles from burrowing under the cylinders. Another effective method is to place PVC pipe around the base of young trees. The pipe can be split with a saw before being placed. It may be necessary to adjust the cylinders as trees grow.
In rural areas such as farm fields, grains or pellets containing zinc-phosphide are the most commonly used poisons for controlling meadow vole infestations, he said. They can be broadcast at rates of 4 to 8 pounds per acre or placed by hand in runways and burrow openings. Certified applicators licensed in the vertebrate category may purchase the product in large quantities from the USDA Supply Depot in Pocatello, Idaho (208-236-6920). Other baits that do not require a pesticide license are available on store shelves, but they are slower acting and usually require multiple applications.
“Homeowners need to be cautious when using toxins in urban areas,” Messmer said. “Poisonous baits should only be used in approved containers and not even considered if there are pets and children around. Removing ground cover, lawn thatch and weeds is the first line of defense. Population control using wooden-based snap traps placed upright in the vole runways will do a good job and mitigate the need of using poison in urban areas.”
Large population fluctuations are characteristic of meadow voles, said Messmer. Population levels generally peak every 2 to 5 years.
“We are already receiving a number of calls this year, suggesting that the snow cover this past winter provided a security blanket to bolster vole survival and magnify the potential for impact,” Messmer said. “Unfortunately, we could be in for a banner vole year.”
Landowners are encouraged to carefully monitor their property because large populations of meadow voles can economically impact crop yields.
“Often a control program may not appear to be justified in comparison to the damage being incurred,” said Messmer. “However, the ‘ounce of prevention rule’ frequently applies in vertebrate pest control, and preventative control measures usually prove to be a bargain.”
For further information on voles, contact Messmer at 435-797-3975 or email@example.com or Nicki Frey at 435-586-1924 or firstname.lastname@example.org.