Lawn Bumps with Small Holes: Moles, Voles, or Crayfish?

Colorado homeowner (3-year-old landscaped yard) has many 1/2-inch tall bumps with 1/8-inch holes underneath, going down ~1 inch. No animals/insects seen. Photos provided.

Analysis

• Perfectly round holes ≠ moles (moles don't surface)
• Voles use mole tunnels but make surface holes
• Crayfish unlikely in Colorado
• Only one hole shown—may be outlier

Recommendation

Consult ICWDM damage identification guides to systematically diagnose. Need more data: number of holes, distribution, time of activity, soil moisture.