Pocket gophers are rodents 5 to 12 inches long that burrow, pushing up soil into flattened mounds. The mounds range from 12 to 24 inches wide and are at least 6 inches high. Pocket gopher mounds, which are clumped in tight groups, have side tunnels attached to main tunnels and noticeably plug the surface opening. Control pocket gophers with a number of methods including deep tilling the soil, flooding its tunnels, traps or poison bait.
Moles are small, burrowing rodents that consume large numbers of insects and earthworms. They often tunnel near the ground surface, causing ridges. Moles, unlike gophers, build up high, volcanolike mounds that have no evident hole and are often spaced in a line rather than clustered. Discouraging the grub population in the lawn and traps control moles.
Voles, also known as field mice or meadow voles, are small, stocky rodents that usually eat herbs and grasses but may feed on roots and seeds. These small, brown rodents create an extensive network of surface runways and underground tunnels. Keeping the landscape neat, preventing unwanted vegetation and avoiding heavy mulch are the best control methods. Anticoagulant baits or mouse traps set with the trigger in the runway are effective.
Crayfish burrow in yards with a dependable water source nearby and high soil water movement. Crayfish, which are largely nocturnal, build 2- to 4-inch towers of mud balls with an inch wide hole at the peak.
Many insects spend at least a portion of their lives underground. Larvae sometimes burrow and emerge as adults, leaving small holes surrounded by loose soil. Solitary bees live in the ground as adults, creating holes about 1/2 inch wide in areas of sparse vegetation. Cicada killers are large wasps that drag immobilized cicadas into tunnels with an entrance up to an inch in diameter. These tunnels are commonly located in dry, bare areas with limited vegetation and may have a u-shaped mound near the entrance.
Several additional pests may occasionally dig in a yard while in search of insects but do not typically burrow in the lawn. These animals include skunks, raccoons, squirrels, birds, opossum, shrews and others.