WHAT'S DIGGING HOLES IN MY YARD? Robert Bystrom

Sometimes it's difficult to identify burrowing animals that have been damaging yards or gardens. They may be nocturnal or so elusive that we never see them. Nevertheless, identifying the animal is an essential step toward controlling or managing the damage.

Often the presence of a burrow or other signs of digging are the only available clue to the animal's identity. And the burrows themselves may be the damage, creating unsightly mounds or depressions that interfere with lawn maintenance and disturb or uproot valuable plants.

Here is a list of diggers and characteristics of their work that can be used to help identify the mystery animal. Please note that some animals that dig do not eat plants. For instance, moles eat soil insects and the plant and root damage caused by their digging is usually incidental.

Evidence	Possible cause
Mounds of soil that cover burrows so that no entrance is usually visible:	Conical mound--eastern mole Rounded mound, often heart shaped--pocket gopher
Multiple tunnels near the surface that raise sod or soil. Tunnel entrance usually not visible:	In wet or swampy areas--star-nosed mole In upland areas--eastern mole
Burrows (usually shallow) with no soil piled near the inconspicuous entrance:	Entrance about 2 inches, near stone walls, rock gardens or foundations, in brush, open woods or gardens--eastern chipmunk Entrance 2 inches or less, in open areas with short grass--thirteen-lined ground squirrel Entrance 1 to 1.5 inches, in open areas with heavy vegetation--meadow vole Entrance about 1 inch, in open areas or woodlands, tunnel just under duff or deeper--shrew (Some shrew species may appropriate vole burrows and runs and several may occupy one burrow system. Shrews usually do not damage plants.) Entrance 2 to 3 inches, near or under buildings, wood piles, shrubbery or rubbish and near a dependable water source (stream, sewer, toilet, etc.)--Norway rat. Several may occupy one burrow system. Entrance 4 inches, near lake, stream or wetland--muskrat
Deep burrows with excavated soil spread around the entrance:	Entrance 10 to 12 inches, in fields, woodlands, under decks, or building foundations--woodchuck Entrance 12 inches, in fields, grasslands, prairies--badger (Badgers are scarce in Minnesota's seven metro counties, but a few may be found in the suburban fringe and developing areas)
Shallow excavations or "divots:"	In turf or mulch--skunk, raccoon, squirrel. This is usually a result of a search for soil insects or, in the case of squirrels, caching or retrieving food, such as corn, acorns or nuts.
Surface runways in grass or tunnels in snow	Strewn with clipped grass or other vegetation in grass or snow--meadow vole Under snow without grass--red squirrel
Potted plants dug up and/or pulled out:	Damage occurs at night--raccoon Damage occurs during the day--squirrel or woodchuck.

W702R
5/2004

top of page

Index to Yard & Garden Briefs