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Big Brown Bat Facts
Big Brown Bat Facts
Connecticut's Most Common "House Bat"
The Big Brown Bat is now the most prevalent species found in Connecticut structures, especially as they have proven more resilient to White-Nose Syndrome (WNS) than smaller species.
- Size & Appearance: Stocky build with a 12–13 inch wingspan and uniform chocolate-brown fur. They are significantly larger than the endangered Little Brown Bat.
- Behavior & Roosting: These bats form maternity colonies in warm attics, barns, and soffits from spring through fall. Because they prefer stable temperatures (80–90°F), they are the species most likely to overwinter (hibernate) inside CT buildings.
- Why They Are in Your Home: Extremely adaptable to suburban Shoreline areas, they enter through gaps as small as 1/4 to 1/2 inch. Their colonies can be noisy and produce significant guano accumulation over time.
- Conservation Status: Listed as a Species of Greatest Conservation Need (SGCN) in CT. They are legally protected, and humane exclusion is the only permitted method for removal.
Expert Insight: Because Big Brown Bats often stay in attics during the winter, you may hear scratching or "chattering" even on cold days. At RF Wildlife / Bat Removal and Exclusion CT, we provide year-round inspections to identify these roosts before the spring activity spike.
Little Brown Bat (Myotis lucifugus)
Little Brown Bat
- Formerly Very Common, Now Rare in HomesOnce one of the most abundant bats in Connecticut, dramatic WNS declines have made sightings less frequent. Still occasionally found in structures.
- Size & Appearance: Smaller (3.1–3.7 inches body length, 8.6–10.5 inch wingspan), glossy brown fur (darker back, paler belly), pointed muzzle with fur, tiny rounded ears. Weighs about ¼ oz.
- Behavior & Roosting: Maternity colonies in attics, behind shutters, or under siding. They like even warmer roosts than big browns. Fly faster (up to 22 mph) and hunt closer to water sources.
- Why in Homes?: Squeeze through tiny cracks; prefer humid, enclosed spots. Guano is smaller, rice-grain sized.
- Conservation Status: Endangered in Connecticut (and federally threatened)—strict protections; maternity season (May–August) bans evictions if pups present.
- Fun Fact: Can eat up to 1,200 insects per hour—excellent natural pest control!
Other CT Bats (Rarely Indoors)
While Connecticut has nine species, most are cave or tree-roosters that seldom cause indoor infestations.
- Cave Hibernators: Northern long-eared, eastern small-footed, Indiana, and tri-colored bats are highly protected (Endangered/Threatened) but typically prefer natural cave environments over human structures.
- Solitary Tree Bats: Silver-haired, eastern red, and hoary bats are "Species of Special Concern." They prefer roosting in foliage and migrate south for the winter rather than entering your attic.
The Specialist's Rule of Thumb:
If you spot bats in your Connecticut home—especially in shoreline areas like Madison, Guilford, or Old Saybrook—it is almost certainly a Big Brown or, less commonly, a Little Brown Bat. Because misidentification is easy and legal protections are strict, a professional structural inspection is the only way to ensure a safe, permanent solution.
"Special Case: Silver-haired Bats"
While typically solitary tree-roosters, I have personally removed Silver-haired bats from CT homes and chimneys. These migratory bats sometimes seek shelter in structures during late fall or early spring. If you find a black-furred bat with 'silver-frosted' tips on its back, it’s a Silver-haired bat—and it still requires professional, humane handling."