If you live in New Hampshire or Maine, you’ve probably had a late summer evening when you’ve looked up at the dusky sky and spotted a few tiny, fast-moving shapes darting and swooping through the air. Chances are, you were watching brown bats at work — our region’s natural pest control squad.
But while these remarkable creatures do an incredible job keeping insect populations in check, they sometimes cross a boundary we’re less excited about: moving into our homes, barns, and outbuildings. Let’s take a closer look at the brown bat species that call New England home, why they sometimes bunk up in our attics, and what you should do if you suspect a colony has set up camp overhead.
Meet the Brown Bats of New Hampshire & Maine
In the forests, farmland, and waterfronts of northern New England, there are two primary brown bat species you’ll encounter — each with its own habits, quirks, and reasons for making themselves at home in your buildings.
Little Brown Bat (Myotis lucifugus)
The little brown bat is one of New England’s most famous native species — or at least it was before a devastating fungal disease known as white-nose syndrome decimated its population.
- Size: Roughly 3 to 4 inches long, with an 8 to 11-inch wingspan
- Color: Glossy brown fur with a slightly lighter underbelly
- Diet: Insects — particularly mosquitoes, moths, beetles, and gnats
- Fun Fact: A single little brown bat can devour up to 1,000 mosquitoes in a single hour, making them one of nature’s most effective pest controllers.
Little brown bats were once one of the most common species found in homes, barns, and outbuildings, especially during the summer maternity season, when females gather in colonies to raise their pups.
Big Brown Bat (Eptesicus fuscus)
As its name suggests, the big brown bat is a heartier, slightly larger cousin to the little brown bat and one of the most resilient bat species in the Northeast.
- Size: 4 to 5 inches long with an 11 to 13-inch wingspan
- Color: Rich chocolate brown with a lighter underside and a robust build
- Diet: Beetles, wasps, and other hard-shelled insects
- Fun Fact: Big brown bats are among the few species hardy enough to hibernate inside buildings like attics, basements, and barns throughout our frigid New England winters.
These bats are often the culprits behind wintertime scratching or fluttering sounds in your attic, as they hunker down for months in dark, undisturbed spaces.
Why Brown Bats Love Homes, Barns, and Outbuildings
Historically, both little and big brown bats roosted in natural cavities: hollow trees, rock outcrops, and caves. But as forests were cut back and development spread, suitable wild roosting sites became scarce. Ever resourceful, these bats adapted by moving into human-made structures that mimicked their natural shelters.
Today, homes, barns, churches, sheds, and abandoned buildings are prime real estate for brown bats seeking:
- Warmth, especially in attics that can remain 90°F or warmer on summer days
- Safety from predators like hawks, owls, and raccoons
- Protection from the elements
- Close proximity to water and insect-rich habitats
Common Roosting Spots in Homes & Barns
- Behind attic insulation
- Inside wall voids
- In barn rafters and hay lofts
- Beneath roof shingles or loose siding
- Inside chimneys (especially uncapped ones)
- Behind shutters and under porch roofs
During maternity season (typically May through August), female brown bats gather in large colonies to give birth and raise their pups in the safety of enclosed spaces. It’s not uncommon for one attic to house dozens to even hundreds of bats.
The Risks of a Brown Bat Infestation
While bats are essential to the ecosystem, they’re not ideal houseguests. Having a bat colony inside your home or barn can lead to:
- Structural damage: Accumulated guano (bat droppings) can corrode wood and insulation.
- Health concerns: Guano is a breeding ground for histoplasmosis, a fungal lung infection, and though rare, bats can carry rabies.
- Unpleasant odors: Guano and urine create strong, musty smells in enclosed spaces.
- Staining and contamination: Droppings can stain walls, ceilings, and stored items in barns or attics.
Bat Protection and Conservation
Due to the devastating impact of white-nose syndrome, both New Hampshire and Maine have declared little brown bats a species of special concern. It’s illegal in many places to harm or intentionally kill bats, especially during their maternity season when pups are unable to fly.
That’s why humane exclusion methods and professional wildlife control are crucial — you want to remove bats safely and legally without disrupting vulnerable populations. Professional bat removal services use humane techniques that protect both homeowners and bat populations.
Brown Bat Removal & Prevention Checklist
If you suspect brown bats have moved into your home, attic, or barn, here’s what you should do:
- Confirm the sounds: Listen for rustling, squeaking, or fluttering noises at night.
- Check for guano: Look for small, pellet-like droppings near entry points and in attics.
- Avoid sealing exits: Never trap bats inside. Wait until professionals confirm safe removal.
- Call a licensed wildlife prevention specialist.
- Schedule a home inspection to identify entry points, roosting areas, and colony size.
- Plan humane exclusion using one-way doors that let bats out but not back in.
- Seal up your home once bats are gone.
- Clean and sanitize contaminated areas.
- Add prevention upgrades like chimney caps, screened attic vents, and soffit repairs.
- Schedule a follow-up to confirm your home stays bat-free.
Many homeowners also choose long-term wildlife prevention services to ensure animals cannot return once exclusion is complete.
Final Thought: Protecting Bats, Protecting Homes
Bats might seem like spooky intruders, but they play a vital role in controlling pests and maintaining forest health throughout New Hampshire, Maine, and beyond. The key is keeping them outside, where they belong.
If you’re hearing strange sounds at night or suspect bats in your barn rafters, take it as a sign to call in a pro and check your home’s defenses. And when you do, you’re helping protect your property and the future of one of New England’s most important — and now endangered — native species.
Bat Awareness Guide for New England Homeowners
Why Bats Matter
- Eat thousands of insects (including mosquitoes) every night
- Essential for forest health and crop protection
- Many species — like the Little Brown Bat — are now endangered due to white-nose syndrome
Common Roosting Spots
- Attics
- Barn rafters and hay lofts
- Behind shutters
- Under roof shingles or loose siding
- Inside chimneys
Signs of Bats in Your Home
- Scratching, rustling, or fluttering sounds at night
- Tiny high-pitched squeaks
- Small, dark, crumbly droppings (guano) near entry points
- Stains around holes, vents, or rooflines
Health & Safety Risks
- Histoplasmosis: a lung infection from bat guano spores
- Rabies risk: though rare, bats can carry the virus
- Property damage from accumulated droppings and urine
What To Do If You Suspect Bats
- Confirm the signs
- Avoid blocking exits — do not seal holes while bats are inside
- Contact a licensed wildlife prevention specialist
- Schedule a home inspection
- Plan humane removal (never harm or kill bats — it is often illegal)
- Seal entry points once the bats are safely excluded
- Clean contaminated areas professionally
- Add prevention upgrades like chimney caps, screened vents, and soffit repairs
Important Local Note
In New Hampshire and Maine, Little Brown Bats are a species of special concern. Removing bats during maternity season (May–August) without professional help is dangerous for pups and often illegal.
When in Doubt — Call a Pro
A wildlife prevention specialist can identify species and colony size, safely remove bats using humane exclusion methods, seal entry points, clean contamination, and install long-term protection. If you suspect bats are present, contact Advanced Wildlife Control to schedule a professional inspection.
Protect Your Home & Our Bats
Bats are essential to New England’s ecosystem. Keep them wild, keep your home safe, and support conservation efforts by using humane prevention services.
