Raised tunnels in a yard are a clear sign of subterranean activity, typically caused by a small mammal pushing up the soil just beneath the surface. These shallow ridges indicate a pest is foraging for food in the upper layers of the earth. While the damage is primarily cosmetic, the tunnels can disrupt grass roots, creating soft spots and harming the overall health of the turf. Understanding the source of this damage is the first step toward effective removal and prevention.
Identifying the Culprit Moles Versus Voles
The distinctive raised tunnel ridges are the signature of the common mole. Moles are insectivores, creating these ridges as they quickly excavate shallow foraging tunnels in search of prey. The surface tunnels are generally closed, appearing as a meandering, raised line of sod about three inches wide. Moles also create volcano-shaped mounds of soil, which are the byproduct of digging deeper, permanent tunnels.
Voles, by contrast, are rodents that feed primarily on plant matter like roots, bulbs, and seeds. They do not create raised ridges, but instead create small, open entry and exit holes, typically the size of a golf ball. Their movement paths are visible as shallow, two-inch-wide, open runways of chewed-down grass on the surface. Knowing the difference is important because their distinct diets and behaviors require different control methods.
Understanding Mole Tunneling Behavior
The creation of shallow, raised tunnels is a direct result of the mole’s high metabolism and specialized diet. Moles are dedicated insectivores whose diet consists mainly of earthworms, grubs, and other invertebrates. They must consume a large volume of food daily, which requires constant foraging.
These surface tunnels, running only one to three inches below the soil line, are temporary feeding runs created rapidly as the mole searches for prey. The mole pushes the displaced soil upward, forming the visible ridge on the lawn. Moles can tunnel up to 18 feet per hour, constantly expanding their foraging territory, which is why new ridges can appear overnight. Moles also create deeper, permanent tunnels six to twelve inches below the surface for main highways and nesting areas.
Immediate and Effective Control Methods
Trapping is the most effective and practical method for immediately removing moles from a yard. To identify an active tunnel, flatten a section of the raised ridge with your foot. If the tunnel is pushed back up within 12 to 24 hours, it is an active run and a good location for a trap.
Several trap types are effective, including the harpoon, scissor, and choker loop designs. Harpoon traps are often the easiest for a homeowner to set and are suitable for shallow surface feeding tunnels. Scissor traps are better suited for deeper, more established runs. When setting a trap, place it firmly into the compressed section of the active tunnel and cover it with soil or turf to block out light. Methods like using sonic devices, flooding tunnels, or applying castor oil-based repellents are generally not effective, as moles can tunnel around the disturbance or ignore the irritant.
Long-Term Yard Modifications to Deter Pests
Long-term mole management involves modifying the yard’s habitat to make it less appealing, focusing primarily on controlling their food source. While moles prefer earthworms, they also readily consume white grubs, the larvae of beetles. Reducing the grub population through beneficial nematodes or targeted insecticides in mid-June to mid-July can help eliminate this food source.
Reducing excess soil moisture can make the environment less habitable for earthworms and other invertebrates, as moles prefer moist, well-aerated soil. Watering a lawn deeply but less frequently encourages deeper root growth and reduces moisture content in the upper soil layer. For a complete solution, installing a physical barrier, such as an underground wire mesh buried two to three feet deep around the perimeter, can prevent moles from migrating into the area.