Nature Notebook – Mole Hills
The numerous soil hills popping up in lawns look a bit like slalom courses. Many people blame thirteen-lined ground squirrels or what they call gophers. However, ground squirrels carefully remove the evidence of their burrowing activity. They seem to disappear into the ground. Moreover, the ground squirrels have been hibernating for the last few weeks.
Moles do not hibernate. They will continue their incessant hunt for soil invertebrates including earthworms and insect larvae. To protect themselves from winter’s temperatures moles construct or renovate deep tunnels below the frost line. The excavated soil is pushed to the surface through short vertical tunnels and deposited in volcano-like mounds. The digging is especially productive on damp days or after rain showers.
Tunnel numbers are higher in the fall as the year’s young disperse and claim their own feeding areas.