Commercial & Infrastructure Services
Bat Exclusion for Bridges & Overpasses
Tampa Bay's bridges are home to some of the largest free-tailed bat colonies in Florida. We provide licensed, FDOT-compliant exclusion services for municipalities, counties, and private infrastructure owners.
Why Bridges?
Why Bats Choose Bridge Structures
Concrete expansion joints, hollow box girders, and the gaps between deck panels create ideal roosting conditions for Brazilian free-tailed bats. A single Tampa Bay bridge can host a colony of 100,000 or more — the Sunshine Skyway and several Hillsborough River bridges are among the most documented roost sites in the state.
Bridge bat colonies are generally considered beneficial — a colony of 100,000 free-tailed bats consumes roughly 1,000 pounds of insects per night. Many municipalities and FDOT actively manage bridge colonies rather than exclude them, installing bat houses and monitoring population health.
When exclusion is warranted — due to guano accumulation on pedestrian paths, structural concerns, or public health issues — it requires a different approach than residential work. Bridge exclusion involves working at height, coordinating with traffic management, and navigating FDOT and municipal permitting requirements.
Bats in a single Tampa Bay bridge colony
Brazilian free-tailed bats — the most common bridge species in Florida
Insects consumed per night by a colony that size
Bridge colonies provide significant mosquito and agricultural pest control
Typical monitoring period for bridge exclusion
Larger colonies may require extended monitoring before final sealing
Bridge exclusion is not always the right call. Many Tampa Bay bridge colonies are managed in place — monitored, not excluded. We assess whether exclusion is warranted before recommending it.
When Exclusion Is Warranted
Reasons to Exclude Bridge Bat Colonies
Guano accumulation on pedestrian paths
Bat guano falling onto sidewalks, bike paths, or public areas below a bridge creates a slip hazard and a histoplasmosis risk. This is the most common reason municipalities request exclusion from specific expansion joints or girder sections.
Structural damage from guano accumulation
Guano is highly acidic. In enclosed box girder sections where accumulation is not dispersed by rain, long-term guano buildup can accelerate corrosion of rebar and concrete. FDOT bridge inspectors sometimes flag this during routine inspections.
Odor complaints near public spaces
Bridges adjacent to parks, marinas, or commercial areas can generate significant ammonia odor during peak colony season. Partial exclusion — moving the colony away from public-facing sections — is often the most practical solution.
Renovation or repair work
Bridge repair and resurfacing projects often require temporary exclusion of bat colonies from the work zone. We coordinate with contractors and project managers to schedule exclusion outside the maternity season blackout and around construction timelines.
Public health incidents
A bat found on a pedestrian path below a bridge creates a potential rabies exposure event. Repeated incidents may prompt a municipality to request exclusion from the sections directly above public access areas.
Lease or liability requirements
Private bridge owners — marinas, industrial facilities, private roads — may face insurance or lease requirements to address bat colonies. We provide documentation and certificates of insurance for commercial accounts.
Municipal, county, or private bridge owner?
We handle permitting, FWC coordination, and project documentation. Call to discuss your project.
Our Process
Bridge Exclusion: How It Works
Site Assessment & Permitting Review
We inspect the structure, document roost locations and colony size, and review applicable FDOT, county, and municipal permitting requirements. Bridge work often requires lane closure permits, traffic control plans, and coordination with the owning agency.
Scope of Work & Compliance Documentation
We provide a written scope covering which sections will be excluded, the exclusion method, materials, timeline, and maternity season compliance. Commercial accounts receive certificates of insurance and Florida wildlife agent credentials.
Traffic & Access Coordination
Bridge exclusion work requires working at height — often from bucket trucks, scaffolding, or under-bridge inspection vehicles. We coordinate lane closures, traffic control, and access with the owning agency or general contractor.
Exclusion Device Installation
One-way exclusion devices are installed at active roost entry points. For bridge expansion joints, this typically involves exclusion netting or foam backer rod systems that allow bats to exit but not re-enter. Secondary gaps are sealed simultaneously.
Monitoring & Verification
We monitor for 3 to 7 nights to confirm the colony has vacated the targeted sections. For large colonies, the monitoring period may be extended. Dusk emergence counts document pre- and post-exclusion population levels.
Final Sealing & Documentation
Exclusion devices are removed and entry points permanently sealed. We provide a completion report with before/after documentation, materials used, and warranty terms — required for most municipal and FDOT project closeouts.
Regulatory Compliance
Permits, Blackouts, and FDOT Requirements
All bat exclusion in Florida — including bridge work — is subject to the April 15 through August 15 maternity season blackout under Florida Statute 379.231. Bridge projects that conflict with this window must be scheduled around it or phased to avoid active roost sections during the blackout.
FDOT bridge work involving wildlife typically requires coordination with the Florida Fish and Wildlife Conservation Commission (FWC). We handle this coordination and can provide the required documentation for project files.
For municipal clients, we provide all documentation required for public records compliance, including scope of work, wildlife agent credentials, insurance certificates, and completion reports.
What we provide for every commercial project
Maternity season applies to all bridge work. April 15 – August 15 exclusion blackout is non-negotiable under Florida Statute 379.231. Projects must be phased or scheduled around it.
Common Questions
Bridge Bat Exclusion FAQ
Can you exclude bats from a bridge that is still open to traffic?
Yes. Most bridge exclusion work is performed from the underside of the structure using bucket trucks or under-bridge inspection vehicles, with no impact on traffic above. Lane closures are only required when access equipment must be positioned in a travel lane.
Do bridge bat colonies need to be fully excluded, or can partial exclusion work?
Partial exclusion is often the most practical approach for large bridge colonies. We can exclude bats from specific sections — the expansion joints directly above a pedestrian path, for example — while leaving the rest of the colony undisturbed. This addresses the specific problem without displacing a large beneficial colony.
What happens to the colony after exclusion?
Excluded bats relocate to other sections of the same bridge, nearby bridges, or natural roost sites. For large colonies, we recommend installing bat houses in the project area to provide an alternative roost and keep the colony's insect control benefits in the vicinity.
Is bridge bat exclusion covered by the maternity season blackout?
Yes. The April 15 through August 15 blackout applies to all bat exclusion in Florida, including bridge and infrastructure work. Projects must be scheduled outside this window or phased to avoid active roost sections during the blackout period.
Do you work with FDOT contractors and project managers?
Yes. We are experienced working as a wildlife subcontractor on FDOT and municipal bridge projects. We provide all documentation required for project files, including scope of work, FWC coordination records, insurance certificates, and completion reports.
How do you handle guano cleanup on bridge structures?
Guano remediation on bridge structures is a separate scope from exclusion. For pedestrian path contamination, we can provide pressure washing and biocide treatment of affected surfaces. For enclosed girder sections with significant accumulation, we assess the volume and provide a remediation estimate.
Related Resources
Commercial & Municipal Accounts Welcome
Licensed Florida wildlife agent. Fully insured. FDOT project experience. Serving all of Tampa Bay — Hillsborough, Pinellas, Pasco, Hernando, Polk, and Manatee counties.