Michigan mammals

Western Little Brown Myotis in Michigan

Myotis lucifugus

Native to Michigan S1 Critically Imperiled in Michigan

Not listed as nonindigenous in Michigan by USGS NAS; native to its Michigan range.

IUCN Red List status

  1. LC
  2. NT
  3. VU
  4. EN
  5. CR
  6. EW
  7. EX

EN – Endangered

Very high risk of extinction in the wild.

Little brown myotis roosting alertly on a wooden beamLittle brown myotis roosting in the corner of an attic beamLittle brown myotis roosting on painted wood sidingLittle brown myotis resting among blue spruce branches
Photo: Steph Brulot-Sawchyn · CC0Little brown myotis roosting alertly on a wooden beamPhoto: LeeAnn Latremouille · CC BY 4.0Little brown myotis roosting in the corner of an attic beamPhoto: Tom Romeo · CC BY 4.0Little brown myotis roosting on painted wood sidingPhoto: Patrick Jackson · CC BY 4.0Little brown myotis resting among blue spruce branches

Western Little Brown Myotis in Michigan, by the numbers

Occasional in Michigan 48th most recorded of 75 mammals logged in Michigan

552 occurrence records
29 with iNaturalist photos
Jun 6, 2026 Last seen in Michigan

Records from 2000–2026.

552 total records count every Michigan occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 533 records with a full observation date.

When to look for the Western Little Brown Myotis in Michigan

Most sightings fall in August.

533 Michigan occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence.

Monthly Michigan records (table)
MonthRecords
January0
February3
March2
April4
May24
June29
July78
August269
September92
October22
November6
December4

Monthly western little brown myotis occurrence records (iNaturalist and GBIF) in Michigan, 2000–2026.

Seasonality

Year-round in Michigan, with recorded sightings peaking in August.

Occurrence map

Where Western Little Brown Myotis has been recorded in Michigan

300 records mapped · zoom and drag to explore

300 Michigan records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Mackinac State Park 22
University of Michigan Biological Station 18
Ottawa National Forest 15
Escanaba State Forest Area 13
Isle Royale National Park 10
Sault Ste. Marie State Forest Area 8
Gaylord State Forest Area 4
Pigeon River Country State Forest Area 3

Protected places with the most western little brown myotis sightings, from the USGS Protected Areas Database plus named mountain ranges, good spots to look, not a full breakdown, so they don't sum to the total.

Where it's recorded in Michigan

CountyRecords
Luce County 131
Mackinac County 61
Cheboygan County 52
Delta County 35
Marquette County 20
Washtenaw County 20
Menominee County 18
Berrien County 18
Chippewa County 17
Gogebic County 14
Keweenaw County 13
Isabella County 10
43 other counties 143

The complete county distribution, spread across 55 Michigan counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Little brown myotis records in Michigan run heavily through GBIF, 546 entries against just 29 from iNaturalist, a lopsided ratio that reflects hibernacula counts at sites like Ottawa National Forest rather than casual photographs of this small, fast-flying bat.

That mismatch matters here: NatureServe ranks the species S1, Critically Imperiled, in Michigan, and the IUCN lists it Endangered globally, both driven by white-nose syndrome, the fungal disease that has collapsed hibernating bat colonies across the Great Lakes since the 2010s. Reports run June through September, tracking summer activity outside the winter hibernacula where the real population crash is measured.

Occurrence data from iNaturalist and GBIF.

Little brown myotis roosting alertly on a wooden beam
Full species profile Western Little Brown Myotis Myotis lucifugus Size 8–9.5 cm3.1–3.7 in Weight 6–13 g0.2–0.5 oz Lifespan 35 yr View the full profile

More mammals in Michigan in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

  • GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
  • iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
  • NatureServe ExplorerCC-BYthe state conservation rank
  • IUCN Red Listattributed factthe global conservation status
  • USGS NASpublic domainnative / introduced status
  • Natural Earthpublic domainthe relief basemap
  • USFSpublic domainnational-forest boundaries
  • USGS Protected Areas Databasepublic domainthe named parks, forests, and refuges behind "notable places to look"