Check the vent flappers and screens
Annual · typically March
Why it matters
Your house exhales through a handful of holes in its walls — dryer vent, bathroom fans, range hood, gable and soffit vents — and every one ships with a cheap plastic door that's supposed to swing shut when the air stops. Those flappers age in sunlight, stick open with lint, and crack in cold snaps. To the wildlife scouting real estate in early spring, a stuck flapper is a lit vacancy sign. March is the deadline for a reason: get ahead of nesting season and this is a screwdriver task; miss it, and federal protections on migratory birds (and bat colonies) can legally freeze your eviction until late summer — with the residents running up the damage all season.
What skipping it costs
$150–$2,500
Every exhaust vent on your walls is a warm, sheltered, pre-drilled birdhouse the moment its $4 flapper stops closing. March is move-in month: starlings pack a dryer vent with nesting straw in two days — a fire risk sitting in a lint stream — and bats in a gable vent become a legally-protected summer tenancy you can't touch until fall. The eviction, cleanup, and duct service run into four figures; the flapper was a hardware-store part.
Two ways to get it done
Do it yourself
You'll need: Ladder for anything above the first floor, Flashlight, Replacement flapper/vent cover if one's broken (~$10–$25), 1/4-inch hardware cloth for screening (never window screen on a dryer vent).
- Walk the walls and look up. Find every vent outlet: dryer, each bath fan, range hood, gable vents. Straw poking out of any of them means you're too late for prevention — skip to the hire section.
- Test each flapper: it should swing free and fall fully shut. Run the dryer or fan for the real test — open with airflow, closed without. Stuck, cracked, or missing doors are $10–$25 like-for-like swaps held on by four screws and a bead of caulk.
- Screen the right way: gable and soffit vents get 1/4-inch hardware cloth. Dryer vents get a proper pest-guard cover with large openings or none at all — never fine mesh, which clogs with lint and becomes its own fire hazard. If you add a dryer guard, cleaning it joins your dryer-vent card.
- Listen before you seal anything. Scratching, chirping, or a flapper that's mysteriously open means occupancy. Closing the door on a nest creates a worse problem — that's the moment to stop and hire.
Hire it out
$100–$250National fair range — local labor moves this number.
A wildlife-aware vent check with minor repairs runs $100–$250. An actual eviction — one-way doors, humane timing, cleanup, and re-screening — is legitimately specialized and priced by the situation; birds in a dryer vent with duct cleanup typically lands in the $300–$600 range.
The pricing rule of thumb: repairs are priced per vent, evictions per animal story. Anyone quoting whole-house exclusion before pointing a flashlight at the one broken flapper is selling the package, not the fix.
Ask the tech
- Which vents did you check, and can I see photos of any damage?
- If something's living in a vent: what's the eviction plan, and does it respect nesting season?
- Are you screening the exhaust vents with hardware cloth, or fine mesh that'll clog with lint?
Red flags you're being upsold
- The full-exclusion package ($1,500–$4,000, every gap on the house) pitched when one $12 flapper is broken. Exclusion work is real and sometimes right — after the actual entry point is identified, not instead of finding it.
- Fine insect mesh installed over a dryer vent. It clogs with lint in months, and a blocked dryer vent trades a bird problem for a fire risk.
- Sealing animals IN — any crew that closes openings without confirming the residents left is manufacturing a dead-animal-in-the-wall service call.
Second opinion time: Any wildlife-exclusion quote over $1,000 when you can point at the single broken vent yourself.
The call
DIY the walk-around and the easy swaps in March, before nesting season locks you out. Hire the eviction if something already moved in — occupied vents are not a DIY.