California mammals

Western Heather Vole in California

Phenacomys intermedius

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 heather vole tucked among moss and wet alpine leavesWestern heather vole moving away through moss and alpine ground cover
Photo: Aerin Jacob · CC BY 4.0Western heather vole tucked among moss and wet alpine leavesPhoto: Aerin Jacob · CC BY 4.0A western heather vole moving through mossy ground cover.

Western Heather Vole in California, by the numbers

Rare in California 164th most recorded of 241 mammals logged in California

42 occurrence records
1 with iNaturalist photos

Records from 2000–2026.

When to look for the Western Heather Vole in California

Most sightings fall in July to August.

42 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
January0
February0
March0
April1
May0
June2
July14
August15
September5
October5
November0
December0

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

Seasonality

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

Occurrence map

Where Western Heather Vole has been recorded in California

42 records mapped · zoom and drag to explore

42 California records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Yosemite National Park 10
John Muir Wilderness 4
Ansel Adams Wilderness 1
Kings Canyon National Park 1
Desolation Wilderness 1

Protected places with the most western heather vole 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
Tuolumne County 15
Fresno County 5
El Dorado County 5
Madera County 4
Siskiyou County 4
Mariposa County 3
Nevada County 3
Alpine County 1
Sierra County 1
Mono County 1

The complete county distribution, spread across 10 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 41 Western Heather Vole records: 0 from iNaturalist and 41 from GBIF. It ranks 166th 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 August, with 10 records in the busiest month. Records appear in 3 of 12 months, so the pattern shows when sightings were documented, not when the species must be present or absent.

California accounts for about 9% of the mapped GBIF records summarized on the national Western Heather Vole page. That’s a modest share of the known record footprint, though differences in survey effort can strongly shape the percentage.

Occurrence data from iNaturalist and GBIF.

Western heather vole tucked among moss and wet alpine leaves
Full species profile Western Heather Vole Phenacomys intermedius Size 11.2 cm4.4 in Weight 40 g1.4 oz Lifespan 4 yr 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"