Musing over moles
Are moles mussing your marigolds, lawn or other areas? Understanding their habits will help you manage their mussings. Unfortunately, mole myths mostly mess up mole management. (Try saying that three times fast!)
The eastern mole, Scalopus aquaticus, is a mostly solitary creature that lives in well-drained, loamy soils. They are woodland and woodland edge animals, though they will venture out into grass turf and gardens in search of their favorite food, the earthworm. While they can swim, if necessary, aquaticus refers more to the webbing on the front feet (which are more like paddles, actually) rather than aquatic habits.
Moles are built for digging. With a bullet-shaped head and nose, powerful shoulder muscles, and large, outward-facing front feet with strong claws, these earth miners literally swim through the soil in search of their prey. Their raised feeding tunnels and occasional mounds of excavated dirt are what raise homeowners' ire. Otherwise, we would likely praise them for their habits. In the process of digging, they mix and aerate soil, provide tunnels for water to reach down to plant roots, and eat many destructive insects such as cutworms and Japanese beetle larvae in addition to a main course of earthworms. They add variety to their diet with supplements of millipedes, centipedes and spiders.
These food habits make moles insectivores, closely related to their cousins the shrews. Like the shrews, moles have a very high metabolism: they must eat quite regularly and often consume more than their body weight in food in a day. During drought and winter months, however, they can survive on much lower quantities.
Being mammals, moles are covered in fur. The fur is all the same length, thin and dense, and will lie in any direction, feeling much like velvet. This allows them to move forward or backward in their tunnels with no fur resistance. At one time, mole skins were considered quite valuable, used both as fur trim and as powder puffs.
As mammals, they also feed milk to their young. Breeding once per year, the female raises two to five young by herself in an underground nest. The young are independent about a month after their birth but don't breed until the following spring.
Moles have eyes that are hidden in their fur and covered with a skin (a type of fused eyelid). As a result, they see poorly and are able only to distinguish light and dark. They have no external ears to hamper their underground movements, but they have a highly developed sense of smell and are deft at detecting ground vibrations.
While you may think there are dozens of moles invading your lawn, there are likely only one or two. They generally are at densities of only one to three per acre. Being loners, except during the breeding season, that means that in most urban or suburban lawns, a few moles are raising a lot of turf. The many tunnels are merely feeding tunnels that are often used only once. With the ability to dig 12-18 feet in an hour--and sometimes faster--moles can tunnel quite a distance in a night's foraging. If the feeding is good, they'll be back the next evening for more.
The mounds of dirt they push up are conical, made much like small volcanoes as the mole pushes excess dirt straight up from below. This distinguishes them from the more fan-shaped mounds made by another underground but unrelated prairie dweller, the pocket gopher.
In addition to the surface tunnels, moles have deeper travel tunnels 6-24 inches below the surface. These lead to a nest of dry vegetation about two feet below the surface, often under a boulder, tree or stump.
Unfortunately, mole digging causes some problems. Their surface tunnels disfigure lawns, golf courses and cemeteries. Their digging can dislodge bulbs and roots, exposing them to air and death, even though they don't eat them. As a result, people who cannot tolerate the tunnels often seek ways to manage the damage they cause.
Many mole myths unfortunately hamper proper management. Though one can find numerous people who will testify to their effectiveness, no scientific studies support the use of sonic or ultrasonic devices, repellents, chewing gum or grain-based poisons in mole control. Having moles also does not necessarily mean you have grubs in your lawn. In fact, you may simply have a healthy, loamy soil filled with earthworms. Don't be fooled by those who say that "all you have to do" is treat your lawn for grubs to control moles. As with any smart pest management strategy, test your lawn for grubs before applying any chemical.
To control moles, knowledgeable consumers generally turn to one of several traps on the market. Live trapping is possible, using a three-pound coffee can as a "pit-fall" trap. The live-caught mole must be released only in areas where it is legal and permission is granted. More commonly, people purchase a type of kill-trap. To mangle a common cliche: a dead mole in the hand is worth more than two ineffective mole devices in the bush!
Whether trapping dead or alive, the active run must be found. Unlike the random surface feeding tunnels that may be used only once, the active run is often straight, comes from a more sheltered burrow area (often shrubs or trees), and is often used daily. To determine it, flatten the raised turf with your foot. Check it again several hours later or the next day. If it is raised up again, you have an active run and the location in which to set your trap. Follow all label directions carefully.
One other possible management strategy is to contract with a local cat, dog or owl. Cats and dogs will often dig up moles and kill them. They will rarely eat them, however. Like shrews, moles emit a strong, glandular odor, which may prevent them from being eaten. Of course, then you still have to fill in the dug holes. Owls, on the other hand, have little or no sense of smell, and will eat moles, if they can catch them.
The other alternative, of course, is to watch the moles as they swim through your lawn, fascinated by their wonderful adaptations for an underground life.