District of Columbia mammals

Big Brown Bat in DC

Eptesicus fuscus

Native to District of Columbia S4 Apparently Secure in District of Columbia

Not listed as nonindigenous in District of Columbia by USGS NAS; native to its District of Columbia 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 Bats (Eptesicus fuscus)Big brown bat flying in daylight with wings spreadBig brown bat flying at night with wings spreadBig brown bat roosting on lichen-covered tree barkBig brown bat roosting on a wooden structure
Photo: Connor Long · CC BY-SA 4.0Big Brown Bats (Eptesicus fuscus)Photo: rhododendrites · CC-BY-SABig brown bat flying in daylight with wings spreadPhoto: Dan Riskin · CC-BYBig brown bat flying at night with wings spreadPhoto: Rita Clare · CC0Big brown bat roosting on lichen-covered tree barkPhoto: Bonnie Isaac · CC0Big brown bat roosting on a wooden structure

Big Brown Bat in District of Columbia, by the numbers

Common in District of Columbia 15th most recorded of 51 mammals logged in District of Columbia

31 occurrence records
28 with iNaturalist photos
Sep 10, 2025 Last seen in District of Columbia

Records from 2000–2026.

31 total records count every District of Columbia occurrence from GBIF and iNaturalist; the map plots a georeferenced sample of 28; the monthly chart covers the 28 records with a full observation date.

When to look for the Big Brown Bat in District of Columbia

Most sightings fall in May.

28 District of Columbia occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence. Based on a small number of dated records; the seasonal pattern may not be representative.

Monthly District of Columbia records (table)
MonthRecords
January0
February0
March0
April0
May10
June5
July4
August2
September5
October1
November0
December1

Monthly big brown bat occurrence records (iNaturalist and GBIF) in District of Columbia, 2000–2026.

Seasonality

Year-round in District of Columbia, with recorded sightings peaking in May.

Occurrence map

Where Big Brown Bat has been recorded in District of Columbia

28 records mapped · zoom and drag to explore

23 District of Columbia records mapped

Notable places to look

Park, forest, or monumentiNaturalist records
National Capital Parks 2
Rock Creek Park 2

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 District of Columbia

CountyRecords
District of Columbia County 22
Other localities 9

The complete county distribution, spread across 1 District of Columbia counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

With 31 records and a NatureServe rank of apparently secure, the big brown bat is one of the more frequently recorded bats in DC. Reports cluster at Kenilworth Park and Aquatic Gardens and Rock Creek Park, both of which offer the insect-rich water and tree cover this bat forages over, and the National Mall’s monuments and older buildings likely supply roosting crevices in place of natural cliffs and caves.

This is a roost generalist rather than a habitat specialist. Big brown bats will use tree hollows, loose bark, and rock fissures where available, but they take just as readily to attics, church towers, and bridge undersides, which is a big part of why they hold on in a built-up city like DC. They feed entirely on flying insects, caught on the wing over water and open ground after dark.

Records span the warmer months, with the heaviest reporting in midsummer, matching when bats are most active and most visible over the District’s parks and waterways at dusk.

Occurrence data from iNaturalist and GBIF.

Big Brown Bats (Eptesicus fuscus)
Full species profile Big Brown Bat Eptesicus fuscus Size 7.5 cm3 in Weight 17 g0.6 oz Lifespan 19 yr View the full profile

More mammals in District of Columbia in the atlas

Data & sources

The data and visualizations on this page draw on these open sources: