With an animal or a bird in the chimney, do not light a fire to drive it out, and do not cap or seal the flue until you know what is in there. Stop using the appliance until the flue is confirmed clear.
An uncapped chimney is a sheltered vertical cavity, which is exactly what a number of species are looking for. Birds nest in them, squirrels get in and frequently cannot get out, and bats roost in them. The sequence matters more than people expect, because one of the likeliest occupants is legally protected. Chimney swifts are a migratory bird species protected under federal law, they nest in chimneys specifically, and they cannot lawfully be removed or sealed in while nesting. So the first step is establishing what is in there, not capping the flue and hoping. Beyond the legal question there is a practical one: a nest is a blockage, and burning an appliance with a blocked flue pushes combustion products into the room. Never light a fire to drive an animal out. Once the flue is clear, a correctly screened cap is what prevents a repeat.
Checks you can do safely
- Listen: scratching, fluttering, chirping and their timing all help identify it
- Look up the flue with a torch from the firebox, without reaching in
- Check the top of the stack from the ground for a missing or damaged cap
- Note the season, since nesting timing narrows the possibilities
- Keep the damper closed to stop anything entering the room
- Do not light a fire, and do not attempt to smoke it out
Animals in the chimney: causes in the order worth checking
Stop using the appliance until it has been inspected
| Possible cause | Rank |
|---|---|
| No cap fitted, leaving the flue open at the top | Most common |
| A cap with a damaged, missing or corroded screen | 2 |
| A warm, sheltered flue that is attractive in nesting season | 3 |
| An unused flue with no airflow and no disturbance | 4 |
| A damaged crown or chase cover creating an additional way in | 5 |
Services this maps to
Related problems
- Water Is Getting In Around My Chimney
- My Chimney or Fireplace Smells: Why, and What Fixes It
- My Fireplace Damper Will Not Open or Close
- Buying a House With a Fireplace, Stove or Unused Chimney
If what you have is not animals in the chimney after all, the full list of chimney problems is grouped by urgency, and the service triage tool takes a symptom and returns the stop condition and the service it maps to.
Common questions about animals in the chimney
Can I just light a fire to get rid of it?+
No. Cruel, it is illegal for protected species, and practically it fills your house with smoke because the nest is blocking the flue. It also risks igniting the nest material inside the chimney, which is a chimney fire by another route.
What is a chimney swift and why does it change things?+
A migratory bird that nests in chimneys and is federally protected. They cannot lawfully be removed or sealed in while nesting, so if that is what you have, the answer is to wait until they have fledged and then cap the flue to prevent a repeat.
How do I know what is in there?+
The sound and the timing are the best clues: chirping from a nest, scratching from a trapped squirrel, rustling at dusk from bats. A technician can look with a camera. Identifying it matters because the correct response differs for each.
There is a squirrel and it cannot get out.+
Squirrels frequently fall into flues and cannot climb the smooth interior. A wildlife removal job instead of a chimney one, and it is time-sensitive. Afterwards, a screened cap stops it happening again.
Can I use the fireplace while there is a nest in there?+
No. A nest is a blockage, and burning with a blocked flue puts combustion products into your room, including carbon monoxide. It also risks igniting the nest itself.
Will a cap stop this happening again?+
A cap with an intact screen is the fix, yes. Most animal entries are into a chimney with no cap at all, or one whose screen has rusted out. A small component that prevents a recurring and expensive problem.
What about bats?+
Bats are protected in various ways and they are also a public-health consideration, so they are handled as a wildlife matter, not swept out. Do not attempt to remove them yourself and do not seal the flue while they are roosting.
Does the chimney need cleaning after the animals are gone?+
Yes. Nest material, droppings and debris remain in the flue, and droppings in particular carry health considerations. The flue is cleaned and inspected before the appliance is used again.
There is a smell but I have not heard anything.+
That can mean something died in the flue, which produces a distinctive odour. It needs removing instead of sweeping past, and it is another reason to establish what is in a chimney before assuming a smell is old creosote.
How do animals get into a capped chimney?+
Through a screen that has corroded through, through a damaged chase cover on a factory-built system, or through a crown that has broken up enough to open a route. A cap that is present is not automatically a cap that is working.
Is this common here?+
Common enough that it is a routine finding, particularly on chimneys that have been uncapped for years and on unused flues. Unused flues are the worst, since nothing disturbs them from one year to the next.
What is the right order of operations?+
Identify what is in there, resolve it lawfully and safely, clean and inspect the flue, then fit a screened cap. Capping first is the mistake, since it either traps something or breaks the law, and sometimes both.