Fact Sheet: English, Spanish.


Big brown bats (USDA Forest Service Southern Research Station Archive,

Silver hair bat

Silver hair bat (Larisa Bishop-Boros, Wikimedia Commons)


Bat exclusion with mesh (M. D. Tuttle, UC Statewide IPM Project)


  • wingspan ranges from a few inches to 17 inches
  • 18 species in Utah

Nesting Habits

  • caves and mines, tree foliage, hollow trees, cracks in rock cliffs and buildings
  • some live in Utah year-round; some are migratory


  • insects


  • major disruptor to building occupants
  • health hazard: could transmit histoplasmosis and rabies

IPM Recommendations

  • Do NOT kill bats; they are protected by law!
  • Do NOT seal cracks and crevices when bats and their young are present (late May - late July).
  • Exclude bats: seal exterior cracks, crevices and areas around pipes and electrical that enter through walls.
  • Exclude bats: use netting that allows bats to leave structures but blocks them from re-entering the building.
  • Construct bat boxes as an alternative roosting site.
  • Keep all exterior doors and windows closed.
  • Keep screens in good repair.
  • Avoid leaving gaps in construction where bats can roost.
  • Seal all cracks and crevices where bats may enter a building. This may take great effort and special equipment.
  • Use the presence of guano (bat feces) and grease markings on siding, etc., to find openings that need exclusionary measures taken.
  • Never handle bats with bare hands.