Washington mammals

Western Little Brown Myotis in Washington

Myotis lucifugus

Native to Washington S3 Vulnerable in Washington

Not listed as nonindigenous in Washington by USGS NAS; native to its Washington 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 Washington, by the numbers

Occasional in Washington 91st most recorded of 145 mammals logged in Washington

285 occurrence records
26 with iNaturalist photos
Apr 24, 2026 Last seen in Washington

Records from 2000–2026.

285 total records count every Washington occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 273; the monthly chart covers the 272 records with a full observation date.

When to look for the Western Little Brown Myotis in Washington

Most sightings fall in July to August.

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

Monthly Washington records (table)
MonthRecords
January4
February0
March1
April3
May20
June52
July83
August94
September12
October2
November1
December0

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

Seasonality

Year-round in Washington, with recorded sightings peaking in July–August.

Occurrence map

Where Western Little Brown Myotis has been recorded in Washington

273 records mapped · zoom and drag to explore

273 Washington records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
San Juan Islands National Monument 45
Washington State Department of Natural Resources (WADNR) State Resource Management Area 21
Alpine Lakes Wilderness 12
Mount Rainier National Park 4
Lake Roosevelt National Recreation Area 1
Skagit-Snoqualmie Wildlife Area Complex 1
Lake Chelan National Recreation Area 1
Gifford Pinchot National Forest 1

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 Washington

CountyRecords
King County 58
San Juan County 44
Clallam County 23
Pierce County 18
Yakima County 16
Chelan County 13
Whatcom County 11
Okanogan County 9
Snohomish County 7
Grant County 7
Skagit County 6
Lewis County 6
22 other counties 67

The complete county distribution, spread across 34 Washington counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

The Washington record for western little brown myotis comprises 285 submissions across the 2000–2026 window. The 26 iNaturalist entries sit alongside 273 GBIF entries, making source coverage a defining trait of this dataset. The ranking assigns this record set position 82 in Washington’s 126-mammal comparison.

The monthly series reaches its high point in August (94 records), compared with February in 0. Its uncounted location leads stretch between North Cascades National Park and Okanogan-Wenatchee National Forest. Observer access, surveys, and archives shape this pattern, so it should not be called abundance.

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 Washington 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"