Species Identification
We Identify the Exact Species
Not all bats are the same. The species roosting in your structure determines the exclusion method, the entry point size, the legal timing, and the remediation scope. We identify before we act.
Why It Matters
Species Identification Changes Everything
A professional exclusion that works for a Brazilian free-tailed bat colony may fail completely for a big brown bat roost. Entry point sizes differ. Roost preferences differ. Maternity timing differs. Identifying the species before exclusion begins is not optional — it's the difference between a job that works and one that doesn't.
Entry point sizing
Brazilian free-tailed bats enter through gaps as small as ⅜ inch. Big brown bats need ½ inch or more. Sealing to the wrong spec leaves the colony a way back in.
Exclusion device selection
One-way exclusion devices are sized and positioned based on species behavior. A device that works for a free-tail colony may not work for evening bats or tricolored bats.
Legal protection status
All Florida bat species are protected under state law. Some species — including the Florida bonneted bat — carry additional federal protections that affect how and when work can proceed.
Maternity season timing
The statewide blackout runs April 15 – August 15. But species-specific maternity timing varies. Knowing the species helps us plan the most effective exclusion window.
Colony size estimation
Different species form colonies of vastly different sizes — from a handful of big brown bats to tens of thousands of free-tails. Colony size drives remediation scope and guano accumulation estimates.
Roost location prediction
Species have distinct roost preferences — tight structural voids, open attic spaces, behind bark, in chimneys. Knowing the species helps us find every roost location in the structure.
Species Guide
Tampa Bay Bat Species
Brazilian Free-Tailed Bat
Tadarida brasiliensisMost commonSize
3.5" body, 11–13" wingspan
Entry gap
⅜ inch
Colony size
Dozens to tens of thousands
Roost preference
Tight structural voids, attics, eaves, soffits
Maternity
May–June birth; pups fly by late July
How to identify
Tail extends noticeably beyond the tail membrane. Dark brown to gray-brown. Fast, direct flight at 40+ mph. Loud chittering at dusk exit.
Key notes
Responsible for the vast majority of residential bat problems in Tampa Bay. Highly colonial and migratory. Scent markers at entry points draw colonies back year after year.
Big Brown Bat
Eptesicus fuscusCommonSize
4–5" body, 12–16" wingspan
Entry gap
½ inch
Colony size
Small — typically 20–300
Roost preference
Attics, wall voids, behind shutters, chimneys
Maternity
May–June; twins common
How to identify
Larger than free-tails. Glossy medium-brown fur. Slow, erratic flight pattern compared to free-tails. Often found roosting individually or in small groups.
Key notes
Year-round resident in Florida. More likely to be found as a solitary bat inside the living space. Colonies are smaller but can persist in the same structure for decades.
Evening Bat
Nycticeius humeralisCommonSize
3–3.5" body, 10–11" wingspan
Entry gap
⅜ inch
Colony size
25–950 females in maternity colonies
Roost preference
Tree cavities, attics, behind loose bark
Maternity
May–June; twins common
How to identify
Dark brown, nearly black. Short, rounded ears. Often confused with free-tails but lacks the free-tail's protruding tail. Slower, more fluttery flight.
Key notes
Common in wooded residential areas of Tampa Bay. Maternity colonies in attics can be significant in size. Often co-roosts with other species.
Tricolored Bat
Perimyotis subflavusLess commonSize
2.8–3.5" body, 8–10" wingspan
Entry gap
¼ inch
Colony size
Small — typically under 50
Roost preference
Foliage, tree cavities, occasionally structures
Maternity
June–July
How to identify
Tricolored fur — dark base, yellow-brown middle, dark tips. Yellowish-orange forearms. Very small. Slow, erratic flight.
Key notes
Less commonly found in structures than free-tails or big browns. Listed as a species of concern due to white-nose syndrome impacts. Requires careful handling protocols.
Southeastern Myotis
Myotis austroripariusLess commonSize
3–3.5" body, 9–11" wingspan
Entry gap
⅜ inch
Colony size
Hundreds to thousands in cave colonies; smaller in structures
Roost preference
Caves, bridges, culverts, occasionally attics
Maternity
April–May (earlier than most species)
How to identify
Woolly, dull gray-brown fur. Long hind feet. Often found near water. Slower, lower flight path than free-tails.
Key notes
More common near Tampa Bay's rivers and wetlands. Earlier maternity timing means exclusion windows may differ from the standard blackout guidance.
Florida Bonneted Bat
Eumops floridanusRare — federally endangeredSize
5–6.5" body, 18–20" wingspan
Entry gap
¾ inch or larger
Colony size
Small — typically under 100
Roost preference
Tree cavities, bat houses, occasionally building voids
Maternity
May–August
How to identify
Florida's largest bat. Very large ears that meet at the midline. Distinctive loud, audible echolocation calls. Dark brown to gray.
Key notes
Federally endangered. Found primarily in South Florida but range extends into the Tampa Bay area. Any confirmed presence requires coordination with Florida Fish and Wildlife Conservation Commission before any work proceeds.
Not sure which species is in your structure?
Species identification is included in every free inspection — no extra charge.
Our Process
How We Identify Species
Dusk emergence observation
We observe the colony exit at dusk, noting flight pattern, speed, silhouette, and echolocation behavior. Brazilian free-tails fly fast and direct; big brown bats are slower and more erratic; evening bats flutter. Flight behavior alone narrows the identification significantly.
Entry point measurement and analysis
The size and location of active entry points are diagnostic. A ⅜-inch gap in a tight soffit void is characteristic of free-tails. A ½-inch gap behind a shutter or at a chimney cap is more consistent with big brown bats. Entry point morphology is part of the identification picture.
Guano examination
Bat guano is species-specific in size, shape, and composition. Brazilian free-tailed bat guano is small (⅜–½ inch), elongated, and contains insect fragments visible under magnification. Big brown bat guano is larger and more irregular. Guano examination confirms or refines the field identification.
Acoustic monitoring when needed
For ambiguous cases — particularly when the Florida bonneted bat or other less common species may be present — we use acoustic monitoring equipment to record echolocation calls. Each species has a distinct call signature that allows definitive identification.
Documentation and exclusion plan
Species identification is documented in writing before exclusion begins. The exclusion plan — entry point sizing, device selection, timing — is built around the confirmed species. This documentation also protects you in the event of any regulatory inquiry.
Common Questions
Species Identification FAQ
Does species identification cost extra?
No. Species identification is part of every inspection we perform. We don't begin exclusion planning without knowing what we're dealing with.
What if I have more than one species in my structure?
Mixed-species roosts do occur, particularly in larger structures. When multiple species are present, the exclusion plan is built around the most restrictive requirements — smallest entry gap, earliest maternity timing, most sensitive protection status.
What happens if a Florida bonneted bat is found?
The Florida bonneted bat is federally endangered. Any confirmed presence requires coordination with the Florida Fish and Wildlife Conservation Commission before exclusion can proceed. We handle this coordination on your behalf and document everything in writing.
Can I identify the species myself?
Field identification of bats is difficult without training. Many species look similar in low light, and the behavioral cues that distinguish them — flight pattern, echolocation, roost preference — require experience to read correctly. Misidentification leads to exclusion plans that don't work.
Do different species require different exclusion methods?
Yes. Entry point sizing, device placement, and monitoring duration all vary by species. A one-size-fits-all approach is one of the most common reasons DIY exclusion fails.
Are all bat species in Florida protected?
Yes. All bat species in Florida are protected under Florida Statute 379.231, which prohibits killing, harming, or harassing bats. The Florida bonneted bat carries additional federal protection under the Endangered Species Act. Professional exclusion — not extermination — is the only legal approach.
Not Sure What Species You Have?
Free inspection, species identification included. Licensed Florida wildlife agent. Serving all six Tampa Bay counties.