Birds or mice nesting in a dryer vent: what to do and who to call

Updated November 10, 2026 · KeystoneProGuide editorial team

What should you do about a nest in a dryer vent?

Stop using the dryer, find out whether the nest is in use and what built it, and have it removed by someone equipped for the job. Then fix the outlet so that it closes properly, without adding a screen. A nest blocks the exhaust as surely as lint does, and nesting material is dry grass, straw and paper sitting in the path of hot air.

The order matters because of one legal point: most birds' nests are protected while they hold eggs or young. Starlings and house sparrows, the two birds that extension services write about as pests of buildings, are not, but you need to know which bird you have.

Why do birds choose dryer vents?

A dryer vent is a sheltered cavity on the side of a house, and cavities are what these birds look for. Penn State Extension says starlings are cavity nesters that build in drain pipes, in holes in walls and ceilings and in any other cavity-like opening. It says house sparrows build large, messy nests of grass, straw, leaves and trash in cavities. The Cornell Lab of Ornithology's NestWatch program says both species live almost always near people and nest in structures.

Angi describes how they get in: debris can force the outside vent cover open and let pests nest inside the duct. A flap held open by lint is an invitation.

When does nesting happen in Pennsylvania?

From early spring through summer. Penn State Extension gives these seasons.

• Starlings breed from April to July and usually raise two broods.
• House sparrows nest mainly from March to September, with two to three broods a year.
• House finches, which also use cavity-like openings in buildings, can breed as early as March in Pennsylvania.

A University of Nebraska extension guide on pest birds adds that they are quick to rebuild, often in the same place.

Is it legal to remove the nest?

It depends on the bird and on whether the nest is in use.

The U.S. Fish and Wildlife Service says most bird nests are protected under the Migratory Bird Treaty Act, and that it is illegal to destroy a nest that has eggs or chicks in it, or one that young birds still depend on. An empty nest is different: the Service says the act does not prohibit destroying a nest that holds no eggs or birds, provided nobody keeps it. Permits to remove an active nest are issued only in very limited circumstances, and people are usually required to wait until the nest is inactive.

Three birds fall outside that protection. Penn State Extension says all birds are protected by state or federal law, or both, except pigeons, house sparrows and European starlings. NestWatch says the same of house sparrows and starlings under the federal act.

That leaves the practical question of which bird it is. Penn State Extension stresses identifying a house sparrow correctly, because every other sparrow is protected, and the house finch, which uses the same kind of opening, is protected too. For a nest inside a cavity, the Fish and Wildlife Service says it can be hard to tell whether birds or eggs are present, and recommends consulting an expert. If you are unsure whether what you plan is lawful, Penn State Extension's advice is to contact a regional office of the Pennsylvania Game Commission before acting.

Who removes it, and what does it cost?

A dryer vent cleaner removes the material and cleans the duct. Where animals are still inside, a wildlife or pest control service comes first.

None of the guides explains its range. Fixr says that if there is any movement in the nest you need a wildlife removal specialist first, and the vent is cleaned afterward. Angi says a full infestation may need a pest control expert. This Old House's advice on seeing nests or droppings in a vent is simply to call a professional.

Ask whoever you call how they will confirm the nest is empty, and what they will do if it is not.

How is the mess cleaned up safely?

Nests carry more than twigs. The Nebraska extension guide says to wear gloves and bag the nesting material, to avoid contact with nest mites and lice.

For rodents the Centers for Disease Control and Prevention is more specific, because of the diseases their droppings can carry.

• Do not vacuum or sweep rodent droppings or nesting materials. The CDC says this can put tiny droplets containing viruses into the air.
• Wear rubber or plastic gloves.
• Spray the nest and the area around it with disinfectant and let it soak for 5 minutes, or as the label says.
• Seal the material in a plastic bag, then inside a second bag.

That first point is worth raising with a vent cleaner, since vacuums and brushes are the tools of the trade. The CDC says to contact your local health department with questions about your own situation.

How do you keep them out afterward?

With a flap that works, not with a screen. This is where good intentions and the building code part ways.

• The residential code Pennsylvania has adopted says the outlet must have a backdraft damper and that screens shall not be installed at the duct termination.
• The Nebraska extension guide, which recommends mesh screens over bathroom and other exhaust vents to stop nesting, makes an exception of dryer vents: use caution, it says, because lint can accumulate and catch fire.
• The home inspectors' association says a screen at the termination can accumulate lint and should be noted as improper.
• Philadelphia's city-owned gas utility, Philadelphia Gas Works, tells customers not to cover appliance vent openings with mesh or netting.

Against that, cost guides list bird guards at $30 to $100. If a guard is offered, ask how it complies with the code's rule.

What the sources do support:

• A hood whose flap closes fully. The appliance makers' association, AHAM, recommends a louvered or box hood style cap.
• A clean vent. A flap propped open by lint is how Angi says pests get in.
• Regular looks. Philadelphia Gas Works says to check outdoor appliance vents all year, because bird nests are among the things that block them. In Pennsylvania the months to watch are March through September.

What should you do next?

If you can see nesting material at the outlet, leave the dryer off and make the call. How often a dryer vent should be cleaned explains how a spring check fits the yearly routine, the cost guide has the full price ranges, and businesses that clean dryer vents are on the dryer vent cleaning directory page.

Sources

1. Controlling Birds Around Farm Buildings, Penn State Extension
2. Landowner's Guide to Wildlife Control and Prevention Laws in Pennsylvania, Penn State Extension
3. Managing House Sparrows and European Starlings, NestWatch (Cornell Lab of Ornithology)
4. Bird nests, U.S. Fish and Wildlife Service
5. Urban Pest Birds: Controlling Damage, University of Nebraska-Lincoln Extension
6. How to Clean Up After Rodents, Centers for Disease Control and Prevention
7. 2021 International Residential Code, Chapter 15: Exhaust Systems, International Code Council
8. Natural Gas Safety, Philadelphia Gas Works
9. Dryer Vent Safety, International Association of Certified Home Inspectors (InterNACHI)
10. How Much Does Dryer Vent Cleaning Cost? [2026 Data], Angi
11. How Much Does Dryer Vent Cleaning Cost? [2025 Data], HomeAdvisor
12. How much does dryer vent cleaning cost?, HomeGuide
13. How much does it cost to clean a dryer vent?, Fixr
14. How To Clean a Dryer Vent, This Old House
15. Clothes Dryer Safety, Association of Home Appliance Manufacturers (AHAM)