Wisconsin mammals

Eastern Red Bat in Wisconsin

Lasiurus borealis

Native to Wisconsin S3 Vulnerable in Wisconsin

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

Eastern red bat roosting among green leaves, disguised as a dead leafEastern red bat in flight against blue skyEastern red bat roosting on a pine branchEastern red bat hanging under tree leavesEastern red bat tucked among white apple blossoms
Photo: NPS Photo · Public DomainEastern red bat roosting among green leaves, disguised as a dead leafPhoto: Chrissy McClarren and Andy Reago · CC0Eastern red bat in flight against blue skyPhoto: Christina Butler · CC BY 2.0Eastern red bat roosting on a pine branchPhoto: Summit Metro Parks · CC-BYEastern red bat hanging under tree leavesPhoto: Rev. Lee A. Payne, Jr. · CC-BYEastern red bat tucked among white apple blossoms

Eastern Red Bat in Wisconsin, by the numbers

Occasional in Wisconsin 43rd most recorded of 75 mammals logged in Wisconsin

86 occurrence records
46 with iNaturalist photos
May 10, 2026 Last seen in Wisconsin

Records from 2000–2026.

86 total records count every Wisconsin occurrence from GBIF and iNaturalist; the monthly chart covers the 82 records with a full observation date.

When to look for the Eastern Red Bat in Wisconsin

Most sightings fall in July to October.

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

Monthly Wisconsin records (table)
MonthRecords
January0
February0
March0
April7
May7
June6
July15
August19
September14
October12
November2
December0

Monthly eastern red bat occurrence records (iNaturalist and GBIF) in Wisconsin, 2000–2026.

Seasonality

Year-round in Wisconsin, with recorded sightings peaking in July–October.

Occurrence map

Where Eastern Red Bat has been recorded in Wisconsin

86 records mapped · zoom and drag to explore

85 Wisconsin records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Kettle Moraine State Forest-Southern Unit 1
Havenwoods Forest Preserve And Nature Center 1

Protected places with the most eastern red 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 Wisconsin

CountyRecords
Milwaukee County 23
Dane County 22
Dodge County 6
Brown County 4
Rock County 4
Portage County 3
Kenosha County 2
Waukesha County 2
Door County 2
Grant County 2
Shawano County 1
Oneida County 1
11 other counties 14

The complete county distribution, spread across 23 Wisconsin counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Wisconsin records place Eastern Red Bats along wooded edges and wetland corridors around Horicon, Kettle Moraine, and southern state parks. The April signal and broader July–October rise bracket spring arrival, summer activity, and autumn migration, when a foliage-roosting bat may also be found grounded or exposed as leaves change.

Only 46 iNaturalist records underpin that pattern, and they represent encounters rather than abundance. Rehabilitation cases, storm-felled bats, acoustic effort, and heavy visitation to parks can all concentrate reports, while tree-roosting animals elsewhere remain difficult to see.

Occurrence data from iNaturalist and GBIF.

Eastern red bat roosting among green leaves, disguised as a dead leaf
Full species profile Eastern Red Bat Lasiurus borealis Size 9.3–11.7 cm3.7–4.6 in Weight 7–13 g0.2–0.5 oz Lifespan Up to 2.6 yr View the full profile

More mammals in Wisconsin 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"