What Are the Dirt Mounds in My Yard?

By Donna Dolinar, Wyandotte County Extension Master Gardener since 2006

It may seem like piles of dirt have appeared in your lawn overnight. They are a mystery and frustrating. In order to rid yourself of the pest, you need to determine which animal is the culprit.

Let’s start with basics:

  • If there is a visible hole and it is smaller than a quarter and has a “U” shaped channel with about an inch around the hole, it is probably a cicada killer wasp. This is a beneficial insect and not very interested in humans. In fact the males are very docile and although they are frightening, will probably leave you alone. The female is also passive, unless you start bothering her nest area. Despite this fact, don’t take chances. Don’t panic but don’t swat at them either.
  • If all the above is correct except there is no “U” channel, it is probably a digger bee. This is also a beneficial insect because it is a pollinator. In general, they are not harmful to humans, unless you threaten them in some way.
  • If the hole is larger than a softball, it is probably a groundhog also known as a woodchuck. This is a real problem. They can weigh up to 10 pounds and are part of the squirrel family. The entrance is usually hard to find and the burrow can be as deep as 5 feet. If this is your pest, call a professional.
  • If the hole is smaller than a golf ball, it is likely to be a vole. This is a rodent and very different from a mole. Voles like plant material and are quite prolific. The good news is that the damage is usually only short lived. The other option is that it is a chipmunk or ground squirrel. These critters will eat both plants and insects and they are very difficult to control.
  • If there is a hole but it seems plugged up, there is a good chance that this is from a mole. This is a mammal that eats insects. Any plant damage is caused by disturbing the roots during burrowing and not from consumption. They particularly like grubs, so if you treat your lawn for grub removal, the moles will find another place to feed.
  • The other option with a plugged hole is a pocket gopher. These folks are herbivores and can be damaging especially to alfalfa fields. These are actually somewhat beneficial in that they mix the soil as they dig, so it is like a living plow. Their excrement will also enhance the soil’s fertility.
  • If there is a mound of dirt and the sod is neatly rolled, you probably are being visited by a skunk. These are nocturnal and will eat whatever they find, adapting to their environment.
  • With a mound of dirt, no hole and no sod damage, this is probably the work of a raccoon. These guys are very destructive to garden vegetables and will forage through your garbage if it is available. They are skilled at entering attics, storage sheds, and chicken coops. They are known to carry a number of diseases that can affect humans, including roundworm and rabies. If they are in your house, call an exterminator pronto.
  • Ants nest and create small mounds of fine dirt. Unless they are in your kitchen, ants are beneficial to the environment. They prey on other insects and their tunnel aerate the lawn.

There are some DIY remedies available. There are poisons that are not recommended since they can also affect other animals and if used in vegetable gardens, can be harmful to humans. Traps sometimes work. If you use a humane trap and want to relocate some of these pests, be sure to check local laws and regulations. There can be rules about where you can release them without incurring fines. Owls are one of the natural predators of some of these rodents and can be encouraged to your neighborhood by installing nesting boxes. Some of the larger pests like raccoons and skunks can be discouraged by dogs, but just be cautious. Remember these are wild animals and can cause physical harm as well as disease. Contact your local Fish and Wildlife agencies to see if they have any recommendations.