Of Moles and Molehills
Text & photos by Neil Soderstrom

Moles infuriate people by creating unsightly ridges in lawns and gardens. These ridges represent the roofs of tunnels that moles push up when forcing themselves through soil like a projectile. This tunneling breaks the roots of grass and other plants, while also exposing roots to air-drying. In addition, moles create molehills when they push piles of unwanted soil up from deeper tunnels.

A single mole can create a crazy network of ridges that may appear to be the work of an extended mole family. Yet, in lawns of modest size, there's usually only one highly territorial mole. Moles don't eat plant roots. Instead, they are insectivores. They tunnel wherever they can find earthworms, insect larvae, centipedes, and other small critters. Blame for root-and-bulb consumption usually belongs with voles, which are mouse-like rodents. On the plus side, moles kill and eat mice and voles.

Tunneling at a pace of 15 18 feet per hour, moles can consume the equivalent of their own body weight each day. They feed around the clock, day and night throughout the year, taking brief rests every few hours. In winter, moles don't hibernate. Instead they follow earthworms below frozen soil (frost line), which can be three and a half feet deep in our region.

In nature, moles serve valuable ecological roles. They consume insect larvae that damage roots. Many of those same larvae would otherwise emerge as plant-damaging insects. Mole tunnels aerate soil, while also serving as thoroughfares for snakes, salamanders, shrews, and rodents. In addition, moles are significant food for foxes, coyotes, bobcats, and owls.

Among the Northeast's three mole species, the eastern and hairy-tailed moles cause the most problems in lawns and gardens. They have head-and-body lengths of about five inches and tails about one and a quarter inches. A third species, the star-nosed mole, is somewhat smaller (to four inches) and has a three-inch tail. It tends to be less noticeable because it favors very wet soils of marshes and shorelines. Its nose has 22 short pink, fleshy appendages that resemble many points of a star.

Moles vs. voles: Moles have large, disk-shaped forepaws with stout, long claws for digging and propulsion. The ears aren't visible, and the tiny eyes are dysfunctional, except for light detection, whereas the eyes and ears of voles are apparent. Moles have a pointed, naked snout rather than the relatively blunt, furry snout of a vole. Voles more closely resemble mice, though with blunter noses and far shorter tails. Our region's voles range midway in size between our largest and smallest moles.

Moles vs. shrews: Moles and their smaller cousins, the shrews, have superficial resemblances. But unlike moles, shrews can't dig well in soil because their forepaws are far more delicate, somewhat like those of mice. Although shrews travel in mole tunnels, they forage mainly aboveground in soft humus and leaf litter.

Options for Controlling Moles
Nature doesn't love a void. That is, removal of an offending mole often results in re-colonization. So before addressing removal by various means, let's consider other options.

Tolerance. If your lawn has barely noticeable ridges that get flattened during lawn mowing or settle naturally after rains, consider mowing higher and tolerating the presence of a single mole. In lawns mowed high (four inch blade settings) with good soil, mole ridges may be hardly noticeable, except when you walk on them and feel them sink underfoot like sponges. Other benefits of high mowing? It shades soil, reducing the need for watering and encouraging grass roots to grow deeper, which helps grass survive droughts.

In fact, a mole can be good for a lawn. Besides aerating soil and consuming root-damaging grubs, the highly territorial resident will kill or help drive off other moles as well as voles and mice. And, even if no mole replaces a mole you've removed, families of voles might infiltrate. Unlike moles, voles dine on roots and bark of ornamental plants, possibly creating a problem worse than mere mole ridges and the occasional molehill. That said, you might want to remove any mole that tunnels on steep slopes, since that can cause erosion and washouts.

Masking mole presence. Two options everyone should consider are converting to no-mow lawns of high grass or planting native plants in lieu any kind of grass. Both are ways to reduce environmental impacts as well as the effort of mowing and multiple trips to refill gas canisters. The bonus: Both no-mow grass and native plants tend to conceal mole ridges.

Deterrents. Various factors determine a soil's appeal to moles. Here are some options for reducing appeal.

•Watering and fertilizing less. Compulsive watering and fertilizing improves soil attractiveness to earthworms and therefore to moles.

• Improving drainage: If your soil is naturally wet, consider improving drainage and also filling low areas that collect water at times.

• Installing mole "fencing": Moles often establish main runways along edges of barriers. So if your lawn or garden border is protected by one-half-inch galvanized mesh sunk two feet deep or a narrow, two-foot-deep trench filled with coarse gravel, moles usually can't enter. You can protect bulb plants by planting inside sunken wire-mesh boxes. And you can protect cold frame plants by stapling wire mesh to the bottom of the frame.

• Biological controls? Some people suggest that Milky Spore will kill enough lawn grubs to leave moles bereft of their favorite food. However, Milky Spore isn't thought to hurt earthworms—the favorite mole food—or other soil critters, so it doesn't reduce the food supply much.

• Frighteners: These tend to be noisemakers or soil vibrators of various types of questionable effect beyond a few feet.

• Helpful predators: These include weasels, foxes, coyotes, opossums, skunks, housecats, hawks, and larger snakes.

Trapping. You can use either lethal traps or live traps. Traps need to be set in main runways, which tend to be longer and straighter than feeding tunnels that instead meander haphazardly near the surface. Once you locate what appears to be the ridge of a main tunnel, tamp it down with your feet. If that ridge soon reemerges, you've located a main tunnel that its maker assumed had collapsed on its own.

• Live trapping: Mole researchers often live-trap by digging a hole to accommodate a one- or two-gallon bucket so the bucket lip is just below the base of a main runway, as shown in the accompanying drawing. On both sides of the bucket lip, they plug the tunnel's two new openings with just enough soil to make the mole believe the tunnel caved in there. Thereafter, a mole hurrying down that tunnel will often blast straight through the soil plug and fall into the bucket with no means of climbing out. First, be sure to cover the hole with a board so no one else falls in. The board also keeps the tunnel looking naturally dark.

Any form of live trapping poses conflicting concerns. New York State forbids transport of most wild animals beyond one's own property, mainly because relocated mammals can transmit diseases to other animals. Besides, many released mammals become easy prey in an unfamiliar or unwelcoming environment.

If you plan to live-trap a mole for release elsewhere, be forewarned that moles have a high metabolic rate and can starve to death in a few hours. So it's wise to place at least cupful of soil with a handful of worms in the bucket and then check the trap every few hours.

• Lethal trapping: New York allows landowners or tenants to control moles by any legal means. One illegal means would be a firearm within municipal limits or near another residence.

• Other "catching" options: Some exasperated homeowners watch for moving earth along main tunnels and then attempt to drive over it with a lawn tractor. Such efforts usually do nothing but expend fuel, tear up turf, and raise your blood pressure. Other people have used axes to slice downward just an inch or two behind soil movement or blast movement with a shotgun. Some people watch for soil movement and use a shovel to scoop the mole into a large tub for release, or scoop first and then whack with the shovel. And then there's heavily-gloved Mole Man Tom Schmidt, of Cincinnati, who's plucked moles out for awaiting cameras. His website, the moleman.com, provides an afternoon of informative, entertaining reading, particularly on the eastern mole.

Neil Soderstrom abridged much of the above from the mole chapter in his newly published Deer-Resistant Landscaping, including Strategies for Controlling 20 Other Pesky Mammals (550+ color photos, 352 pages).

Repellents & Poisons?

Research suggests that repellent odors, based on home recipes and commercial products aren't effective. Even if a repellent, such as mothballs, forces a mole to abandon a portion of a tunnel, the mole can easily dig a detour. Besides, mothball naphthalene is a soil toxin.

Poisons seem the worst possible option because they could be ingested directly by children, pets, predators, and secondarily by scavengers that eat the poisoned mole. Besides, poisons can contaminate the soil and can wash into watercourses and settle into wells.