Bird Nest in the Dryer Vent: What to Do

Signs there is a bird in the vent

Birds look for a sheltered hole with a little warmth, and an outside dryer hood with a stuck or missing flap fits that description. Starlings and sparrows are the usual tenants, and spring is when they move in. The clues are easy to spot once you know them.

• Chirping or scratching from the wall behind the dryer, loudest in the early morning
• Twigs, grass or feathers sticking out of the outside hood
• Birds flying in and out of the vent opening
• A flap that stays open when the dryer is off
• Clothes taking much longer to dry, or the dryer shutting off hot
• A bad smell from the vent or the laundry area

Why a nest turns a vent into a fire risk

A nest is a tight bundle of dry, light material, and in a dryer vent it sits right in the path of hot exhaust. It also works like a plug. With the outlet blocked, lint stops leaving the duct and piles up behind the nest, airflow drops and the dryer runs hotter. Dry grass and a growing mat of lint in a hot, slow duct is a bad combination.

The U.S. Fire Administration's dryer safety flyer says the risk of a dryer fire is higher when lint filters and vents are not cleaned, and asks homeowners to check that the venting behind the dryer is not damaged, crushed or restricted, and that the outdoor vent covering opens when the dryer runs. A nest fails every one of those checks at once.

Gas dryers and carbon monoxide

A gas dryer burns fuel to make its heat, and the vent carries the combustion gases outside along with the moist air and lint. When a nest blocks the outlet, those gases have nowhere to go but back into the laundry area.

Carbon monoxide is dangerous, and you cannot see or smell it. A CO alarm near the laundry, plus one on each sleeping floor, is cheap protection. If an alarm trips or a family member feels sick, leave the house and ring 911 or the gas company once you are out.

Eggs, chicks and the law

Before anything is pulled out, find out whether the nest is active. The U.S. Fish and Wildlife Service explains that the Migratory Bird Treaty Act prohibits the take of protected migratory bird species without prior authorization, and that it covers species native to the United States, not nonnative, human-introduced species.

Which list a particular bird falls on is not something to guess from the laundry room. If there are eggs or chicks, call a wildlife control service or your state wildlife agency, describe the bird, and ask how to handle it. Keep the dryer off in the meantime. None of this is legal advice.

A live bird trapped in the duct

A bird that wandered in and cannot turn around may find its own way out through the hood if the dryer stays off and the laundry area is quiet. Give it a few hours. Do not run the dryer to blow it out, which can kill it and pack it deeper into the duct, and do not reach into the duct by hand.

If the bird is stuck in the transition hose right behind the dryer, the dryer can be pulled out and the hose disconnected so the bird can leave through a window, but only if you can do that without crushing the hose or yourself. When in doubt, call a wildlife service.

A dead bird or an old nest

A sour smell from the laundry area or the outside hood often means a bird died in the duct. The remains, the nest and the lint packed behind them all sit in the same run, so the duct should be cleaned end to end. Wear gloves for anything you can reach at the hood, and leave the duct inside the wall to someone with rotary brushes and a vacuum that clears it without pushing debris deeper.

An empty nest from last season still needs to come out. It keeps blocking airflow after the birds leave, and old nests can carry mites and insects that wander into the laundry area once their hosts are gone. Nest material also tends to fall back into the duct when the flap is pushed open, so pulling only what you can see at the hood often leaves the larger part behind.

Where vents end in local homes, and why it matters

The vent's exit point decides how easy it is for birds to reach it. Rowhouses and brownstones often vent out the rear wall from a basement laundry, sometimes only a short way above grade, where a crushed hood is common. Colonials and split-levels in New Jersey and suburban Pennsylvania often run the duct up through the attic to a roof vent, which birds like because it is high, quiet and rarely looked at. Apartments and condos may share long runs that end on the roof.

Roof terminations are the hardest to inspect yourself, and the most likely to hold a nest for a full season without anyone noticing. Long drying times in spring are often the first clue.

What the cleaning visit involves

Clearing a nest properly is a full vent service, not a quick grab at the hood. The work follows the exhaust path from the back of the dryer to the outside, so nothing is left halfway down the run.

• Pull the dryer out and inspect the transition hose; plastic or crushed hose is replaced with the metal duct the dryer manual calls for
• Remove the nest and any remains from the hood end, bagging material rather than pushing it inward
• Brush and vacuum the full duct from both ends, including elbows and any roof section
• Check that the outdoor flap opens with the dryer running and closes flat when it stops
• Measure airflow at the hood and confirm drying time is back to normal on the next load
• Seal gaps around the duct where it passes through the wall

Keeping birds and mice out for good

The fix is a hood that closes when the dryer is off. A hood whose flap or louvers shut properly keeps birds out, and a hood with a broken or warped flap should be replaced rather than patched. Guards made for dryer exhaust can help, but avoid fine screens or mesh over the outlet: dryer exhaust code language says screens are not to be installed at the duct termination, because lint clogs them and blocks the vent.

Mice usually get in through a hood that does not close or through gaps around the duct where it passes through the wall. Those gaps are sealed from outside and the flap is checked to make sure it sits flat. During a dryer vent cleaning, we remove nests, clean the full duct from dryer to hood and fit a proper hood where the old one has failed.

A quick look at the hood each spring, and again after a heavy storm, catches a stuck flap before a bird finds it. If the hood is on the roof or high on a rear wall, ask for it to be checked during the annual vent cleaning instead of climbing to it.