California mammals

Western Bonneted Bat in California

Eumops perotis

Native to California SNR Unranked in California

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

IUCN Red List status

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

LC – Least Concern

Widespread and abundant; not at risk.

Western mastiff batLive western bonneted (mastiff) bat perched on a rock, ears and face visibleWestern Bonneted Bat (Eumops perotis)
Photo: RatioTile · CC BY-SA 4.0Western mastiff batPhoto: RatioTile · CC BY-SA 4.0Live western bonneted (mastiff) bat perched on a rock, ears and face visiblePhoto: Vincent A. Vos · CC BY 4.0Western Bonneted Bat (Eumops perotis)

Western Bonneted Bat in California, by the numbers

Rare in California 188th most recorded of 241 mammals logged in California

422 occurrence records
16 with iNaturalist photos

Records from 2000–2026.

422 total records count every California occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 405 records with a full observation date.

When to look for the Western Bonneted Bat in California

Most sightings fall in August.

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

Monthly California records (table)
MonthRecords
January12
February10
March43
April23
May49
June44
July28
August62
September34
October18
November54
December28

Monthly western bonneted bat occurrence records (iNaturalist and GBIF) in California, 2000–2026.

Seasonality

Year-round in California, with recorded sightings peaking in August, with a smaller rise in November and March.

Occurrence map

Where Western Bonneted Bat has been recorded in California

300 records mapped · zoom and drag to explore

300 California records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Hain Wilderness Area 1
Pinnacles National Park 1
Joshua Tree National Park 1
Santa Susana Pass State Historic Park 1
Sierra National Forest 1
Santa Monica Mountains National Recreation Area 1
Colonel Allensworth State Historic Park 1

Protected places with the most western bonneted bat 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 California

CountyRecords
Los Angeles County 239
San Diego County 53
Kern County 34
San Bernardino County 27
Riverside County 22
San Benito County 21
Fresno County 5
Orange County 4
Tulare County 4
San Luis Obispo County 4
Sacramento County 1
Butte County 1
5 other counties 7

The complete county distribution, spread across 17 California counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

California’s combined state files contain 435 Western Bonneted Bat records: 16 from iNaturalist and 419 from GBIF. It ranks 189th among 243 mammals in this California record comparison, placing it in the lower third. That’s a ranking of submitted records, not a head count of animals.

The monthly series reaches its high point in October, with 5 records in the busiest month. Records appear in 9 of 12 months, so the pattern shows when sightings were documented, not when the species must be present or absent.

California accounts for about 55% of the mapped GBIF records summarized on the national Western Bonneted Bat page. That’s a large share of the known record footprint, though differences in survey effort can strongly shape the percentage.

Occurrence data from iNaturalist and GBIF.

Western mastiff bat
Full species profile Western Bonneted Bat Eumops perotis Size 15.7–18.3 cm6.2–7.2 in Weight 57 g2 oz View the full profile

More mammals in California 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"