"Hi Eric- Just a quick question regarding those nasty voles that played havoc on a lot of our neighbors grass this year. I was nominated to email you from our homeowners association and ask what is the best procedure to use in getting the grass back to its original state. Should you rake the dead grass? Is there something to use to prevent this in the future? Any information you can give us would be appreciated. Thanks" April 2010. ...from our friend Susan. She's the 5,343rd person to ask those questions this spring and there are many who ask every year.
This will require more than a brief blog can cover so I'll put up a lawn-care info sheet in the next day or two. (see reference). Voles are not moles. Moles eat insects. Voles are not mice but they are called meadow-mice. They look like hamsters or small gophers and are as destructive and far more numerous.
Voles are meat. (Microtus montanus-Mountain Vole / Microtus longicaudus - long-tailed vole / Lemmiscus curtatus - Sagebrush Vole). (See also lemmings) The role of a vole in the ecosystem is to convert plant material into meat. Every native and non-native carnivore in our forests, fields and skies eats voles. Owls, hawks, ravens, eagles, herons, gulls, snakes, martins, weasels, badgers, foxes, bobcats, mountain lions, coyotes, and many more I'm sure, all eat voles.
Voles spend much of their summers in tidy runways through tall grasses, often near water but they are present everywhere. They are fast diggers and burrow underground but are happy to use tunnels left by moles, gophers or ground squirrels. Voles love the condominium-like dwellings created in man-made rock walls. The females mature to produce more voles in less than a month, up to three times a year and they have 4-8 pups in every litter. They have the "highest reproductive potential" of any mammal. These two sites have loads of useful information: U.C. Davis I.P.M. or Cornell / Clemson et. al The Internet Center for Wildlife Damage Management Voles experience wide population fluctuations depending on predators and weather.
Voles will eat just about any plant material, leaves, bark and roots. In winter, voles thrive, unmolested, in the subnivean environment (the world under the snow). The longer the snow-cover the more they eat (we always say that when ice skating is good voles suffer). Under cover, voles burrow with ease through the granular snow at the soil surface. They eat lawn grasses, perennials, bulbs, and the trunks of shrubs and trees when they bump into them. Roses are a favorite food. When our snows melt, the old tunnels, packed with vegetation become apparent.
There's not much you can do for a woody plant or perennial that's had it's roots eaten but lawns usually recover well. Most of our parks and golf courses have voles, probably millions of them. I'm not sure but several tens of thousands per acre would not surprise me at all. (at some locations in Nevada, populations have been estimated as high as 25,000 voles/acre)
The beauty of lawn as a ground cover is that it is durable and resilient. Bluegrass is, by far, the most aggressive weed we have. It will spread underground during winter. Voles USUALLY clip the grass very short without killing it so most of the time lawns recover from vole damage to look great by mid-May. We rake off the dead grass and pine needles so the lawn can see light and receive air, we top-dress with dark finished compost to absorb warmth, hold a little moisture and nutrition (Kellogg's Topper) and we give it a little water when it needs it. As soon as you put down Topper, the lawn looks great. The dark brown layer of mulch contrasts with the emerging green grass and you will FEEL better. If there are spots that don't seem to be recovering by mid-May or within a couple of weeks after snow-melt, then go ahead and mix a little 80/20 lawn seed with Topper and Dr.Earth lawn food to sprinkle in those areas. In the warmer days of May the perennial rye seed will germinate quickly while the bluegrass seed takes its time.
I often put smoke bombs down the open vole holes before filling them with sandy topsoil. Mousetraps beneith a piece of plywood over bricks and above their holes, baited with peanut butter has worked well. The most effective trapping technique we've seen uses a bit of rain-gutter and mouse traps (Vole Trapping). Aeration of laws in late fall may be a deterrent. The ONLY large-scale success I've seen in repelling voles from lawns is using Biosol organic fertilizer in late fall. Biosol is labeled as an organic fertilizer for every imaginable manner of crop, landscape and restoration work. It is not a repellant. Ask any ski area revegetation specialist and he'll tell you that "you can grow grass on a lift-tower with Biosol". For some reason, about eight of ten clients who use it according to the label have a significant reduction in vole damage. And even when there is significant vole damage, lawns with a fall application of Biosol recover very quickly.
We had more plants eaten by voles and rabbits this past winter than we've ever had before. Plants that we've always thought of as "immune" to voles were devoured. I've got to run outside now to rake up a few more piles of grass and pine needles before the next set of snow storms. Spring will be here eventually.