New York mammals

Big Brown Bat in New York

Eptesicus fuscus

Native to New York S5 Secure in New York

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

Big Brown Bat in New York, by the numbers

Common in New York 27th most recorded of 102 mammals logged in New York

466 occurrence records
294 with iNaturalist photos
Jul 10, 2026 Last seen in New York

Records from 2000–2026.

466 total records count every New York occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 300; the monthly chart covers the 447 records with a full observation date.

When to look for the Big Brown Bat in New York

Most sightings fall in July to August.

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

Monthly New York records (table)
MonthRecords
January27
February24
March30
April33
May60
June33
July77
August93
September21
October17
November13
December19

Monthly big brown bat occurrence records (iNaturalist and GBIF) in New York, 2000–2026.

Seasonality

Year-round in New York, with recorded sightings peaking in July–August, with a smaller rise in May.

Occurrence map

Where Big Brown Bat has been recorded in New York

300 records mapped · zoom and drag to explore

300 New York records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
Long Island 9
Harriman State Park 5
Reinstein Woods Nature Preserve And Environmental Education Center 4
Fire Island National Seashore 3
Mine Kill State Park 3
Green Lakes State Park 2
Beaverkill Campground 2
Niagara River corridor 1

Protected places with the most big brown 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 New York

CountyRecords
Tompkins County 59
Albany County 52
Ulster County 36
Suffolk County 19
Onondaga County 18
Monroe County 17
Erie County 16
Cayuga County 16
Orange County 15
Kings County 14
Westchester County 13
Dutchess County 12
43 other counties 179

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

New York’s records for the big brown bat cluster on Long Island, with smaller counts around Adirondack Park and Catskill Park, 466 records in all. It’s an occasional presence in this data, not because the species is scarce, but because it roosts in places people don’t always think to check.

Long Island’s buildings do the job of a cave

Long Island has little of the rock crevice and cave habitat this bat can use elsewhere, but it doesn’t need that here. Big brown bats roost readily in attics, barns, church steeples, and bridge joints, and Long Island’s mix of older houses, farm outbuildings, and shoreline structures gives them exactly that kind of shelter. In the Adirondacks and Catskills, the same species falls back on tree bark, rock crevices, and cliff cracks instead.

New York’s own white-nose syndrome story

Big brown bats are recorded here through the same winters that gutted New York’s cave-hibernating bats. White-nose syndrome, the fungal disease that has killed millions of North American bats since it was first documented in a cave near Albany in the winter of 2006 to 2007, hits little brown bats and Indiana bats hardest. Big brown bats tolerate colder, drier winter sites and have fared better, which is part of why this species still turns up across the state while some of its cave-mates have all but vanished from New York’s hibernation sites.

Two summer peaks, not one

Records rise in May, dip briefly, then climb again through July and August. That double peak likely reflects maternity colonies settling in early summer, followed by young bats taking flight and feeding heavily on beetles and other insects before fall.

Status in New York

NatureServe ranks the big brown bat S5, secure, and it’s native to New York. Its ability to use buildings alongside natural roosts has made it one of the state’s more resilient bats through a period that has been brutal for several of its relatives.

Occurrence data from iNaturalist and GBIF.

More mammals in New York 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"