NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/873551
54 NEBRASKAland • OCTOBER 2017 Becoming a Ground Hole Detective By Adam Jones H ave you ever been strolling along a trail, or walking through your backyard, and discovered a series of small holes no bigger than a dime? Maybe you found a large, messy hole large enough to reach into and wondered: how did this happen? Did an animal create this opening and why? Is it their home or were they looking for food? Mysterious holes can appear with no guilty party in sight. When holes and excavations appear, put on your detective hat and look for hints as to what was there and why it created the hole. First, it is helpful to note the season, location, habitat and hole size. Children playing (children often find it fun to make tunnels and forts in dirt), rotting roots, and running water (sink hole) issues are usually the go-to suspects, but after ruling out these possibilities, most likely you are looking for a wild animal or even an insect. Often you will see scratch marks or shallow holes in the ground with no mounds. There are many explanations for these soil disturbances. If you are observant, you may notice small holes as if something were poked into the ground with the absence of mounds or loose soil. Most likely, the miscreants are birds looking for food. Most common in the spring and fall when the soil is moist, you may have a healthy population of earthworms. These annelids create 1-inch tall piles of small, granular pellets of soil (castings) with no visible holes. Holes or "divots" 2 inches in diameter, shallow, with no mound of soil around them may be squirrels digging buried nuts and other food. Three- or four-inch wide, cone- shaped holes may be a hint that skunks and raccoons, active during the dark of night, have been digging holes and divots in the ground to look for grubs and other insects. Both of these animals have been known to peel back newly laid sod. There are some common clues for animals that burrow, and noting the following information will help you sleuth out the particular critter. Mounds A key step to diagnosing holes is investigating for mounds of soil. If the holes have raised dirt covering or surrounding their entrance, you can narrow your list of suspects. Ants, crickets, solitary bees, and beetles: Holes are one-quarter to one-half of an inch in diameter with soil mounds extending up to 3 inches across. Their tunneling helps to aerate soil. Mole crickets, one of 13 species of grasshoppers and crickets in the state, for example, are named because they tunnel underground like moles and create burrows with their shovel-like front legs. Solitary bees (or ground bees) and beetles: Holes are surrounded by a 2-inch mound of loose soil in urban and natural environments. These insects prefer to live underground during their adult stage. June beetles and Japanese beetles burrow into the soil to lay their eggs. You will also find fecal matter around the entrance to the burrows. It is often difficult to determine what may be causing these particular holes. Part of detective work includes the "stake- out," and this is one of those times. Wait and watch, and the hole will eventually show you the critter. Cicada killers (cicada hawks): With a 1 ⁄2- to 1-inch diameter hole or tunnel used to drag paralyzed cicadas into, these solitary wasps choose sites with specific characteristics: well-drained, light-textured soils in full sunlight that are near trees harboring cicadas. Cicada killer wasps, often seen carrying a cicada, are large, black and pale yellow wasps. The adult female wasp will paralyze the cicada with her venomous sting. Then she carries the cicada into the Get out the measuring tape for a day of sleuthing. Ants near a series of underground holes. A black widow spider clings to its web. PHOTO BY CHRIS HELZER PHOTO BY CHRIS HELZER PHOTO BY CHRIS HELZER A cicada killer wasp drags a cicada back to its hole. PHOTO BY JULIE GEISER