Health and Property Risks From Nuisance Birds

Nuisance birds bring two categories of problems – health risks and property damage.

The droppings are the biggest health concern. Accumulated bird droppings in attics, on rooftops, under bridges, and along ledges can carry histoplasmosis, cryptococcosis, and salmonella.

The droppings themselves are acidic enough to corrode painted metal, concrete, signage, and rubber roofing material over time.

Nesting material is the second issue. Bird nests bring mites, lice, and other parasites into the structure, which then move into living spaces or animal pens.

Inside dryer vents, packed nesting material blocks the duct, creates a fire hazard from trapped lint, and can back carbon monoxide into the home if the dryer is gas.

European starlings, per the Cornell Lab of Ornithology profile, are aggressive cavity nesters that will haul hundreds of pieces of grass, twigs, and litter into a wall or attic space. House sparrows do similar work on a smaller scale in vents and exhaust hoods.

Great-tailed grackles concentrate damage outside, dropping enough waste in retail parking lots and on parked cars to become a real sanitation problem for shopping centers and restaurants.

The longer a bird population sits on a building, the more material accumulates and the more expensive the cleanup gets. That is the case for handling the birds early rather than waiting.

Nuisance Birds in the Houston Area

Three species drive most bird control work in the Houston metro – house sparrows, European starlings, and great-tailed grackles.

House sparrows are an introduced species and are not federally protected, which gives us flexibility on how we handle them.

They favor dryer vents, gable vents, exhaust hoods behind restaurants and grocery stores, and the back ends of strip-center signage. Their nests are messy fibrous packs of grass, paper, and feathers that fall apart in your hand and bring mites.

European starlings are also introduced and not federally protected. They are cavity nesters, which means open eaves, broken roof vents, attic gable vents with torn screens, and the larger weep holes in brick veneer all become starling nesting sites.

Great-tailed grackles are a different conversation – they are a native species and are federally protected. You see them flocking by the thousands in retail parking lots and big-box shopping centers at dusk, roosting in the oaks and on the rooflines, and leaving heavy droppings on cars below.

Pigeons, swallows, woodpeckers, and chimney swifts also come up in our work occasionally, and several of those are federally protected as well.

Every technician on our crew is a certified Ridge Guard Installer, a certified Bird Barrier Installer, and Advanced Metal Fabrication certified, which is the credential set required to identify these birds correctly and install the right exclusion product on the right surface.

Signs of a Bird Problem

Most homeowners and property managers do not notice birds until the damage is well underway. Here is what we look for on an inspection.

• Concentrated droppings under one spot point straight up to where birds are roosting or entering.
• Stains or grease lines on stucco, brick, or siding usually mark a repeat entry point.
• Nesting material visible at a vent or gable almost always means an active nest behind it.
• Chirping or scratching from a wall, attic, or chimney tells you birds are inside, and the sound peaks at dawn and dusk.
• Birds repeatedly flying to and from the same point confirm an entry into the building.
• A dryer running hot or taking longer than usual can point to a sparrow nest blocking the duct.
• Mites or small insects appearing in a room with an outside wall often come from an old nest behind the drywall.

The longer these signs go uninspected, the more material stacks up inside the cavity, and the bigger the cleanup becomes.

The Critter Team carries a Texas nuisance wildlife removal permit, full liability insurance, and workers’ compensation, which is what allows our crew to handle the inspection, removal, and exclusion as one job.

Reading those signs correctly at the start of a job is what determines whether we set up to remove a nest, install exclusion only, or do both at the same time.

Bird Removal and Exclusion

The Critter Team handles bird control as one multi-step job rather than a sequence of separate trades.

The process starts with an exterior inspection that maps every ledge, vent, gable, soffit run, sign, and rooftop unit. For species we can legally trap and remove, like house sparrows and European starlings, our crew handles live removal and nest removal as part of the work.

For federally protected species, we never trap or harm the bird. The U.S. Fish and Wildlife Service Migratory Bird Treaty Act covers most native species in the country, including grackles, swallows, woodpeckers, and chimney swifts.

For those birds, our work is built around deterrence and exclusion – changing the surface so the bird no longer lands or nests there.

Cleanup is its own phase on heavy-contamination jobs, with soiled insulation, droppings, and nesting material removed before we close anything up.

Exclusion materials we use include galvanized mesh on vents, 23-gauge aluminum cut and painted on-site for soffit and fascia gaps, copper or stainless mesh in weep vents, and clear sealant on small openings. We do not use spray foam or steel wool because both fail under Houston heat and humidity.

Once the work is in, it carries our written warranty – one-year on standard exclusion and a three-year option on larger projects. Everything our crew installs is something they can come back and inspect themselves, since the whole job stays in-house.

Bird Prevention and Proofing

Most bird problems trace back to small openings and surfaces that birds find usable as nest sites or roosts.

Preventing the next problem usually means closing those openings before the birds find them.

On a home, that often involves screening every gable and dryer vent, capping the chimney, sealing the gaps where the soffit meets the brick or stucco, and checking the brick weep holes for the size that admits sparrows.

On a commercial building, prevention focuses on the ledges, signage, awnings, parapet walls, and HVAC roof equipment that birds use for roosting.

Spike systems, netting, ledge slope products, and other deterrents each fit different surfaces, and the wrong product on the wrong surface fails fast.

Routine maintenance is the other half of prevention. A pulled-back fascia, a torn vent screen, or a missing chimney cap will turn into a bird entry within a season if nothing is checked.

Property managers benefit most from a periodic walk-around of the roofline and the ground-level dropping zones, looking for the early signs covered in the section above.

Landscaping and food sources matter too – dumpster lids that do not close, open trash storage, and unmaintained landscaping all support larger flocks.

Our team can put together a proofing scope tailored to a single home or a multi-building site, with the same written warranty covering proofing and removal work.

The Critter Team received the 2025 Wildlife Removal Directory Excellence Award for the kind of long-term proofing work that prevents repeat calls.

Frequently Asked Questions