Chimney-top parts
Animals in the chimney
An open flue is an attractive shelter. Here is how to tell if something has moved in, and what to do about it.
Short answer. Scratching, chirping or rustling in the chimney, debris in the firebox, or a sharp smell usually means an animal or nest. Do not light a fire. Removal rules vary by species and place, so a wildlife professional may be needed, and a properly fitted cap prevents a repeat.
Signs
| What you notice | Possible cause |
|---|---|
| Scratching or chirping | Birds or small animals in the flue |
| Twigs, leaves, feathers in the firebox | Nest material falling down |
| Sharp or rotten smell | An animal or nest in or below the flue |
| Smoke refuses to rise | A nest blocking the flue |
What to do
- Do not light a fire. A blocked flue sends smoke and gases into the house.
- Keep the damper closed if you can, so an animal does not come into the room. If it has already, open a door or window to the outside and leave the room.
- Removal rules depend on the species and where you live. Some animals are protected, and nesting seasons may restrict removal. A wildlife professional can advise.
Preventing a repeat
A cap with a screen keeps animals and rain out of the flue. A top-sealing damper also closes the flue. See Chimney cap vs. chase cover and Why is my damper not working?.
After the animal is gone
Have the flue swept and inspected. Nest material is flammable, and animals can damage a damper or cap.
Common misconceptions
"Smoke will drive them out." It can harm both animals and the home.
"A cap is only for show." It keeps animals out.
About this guide. Published by Dr. Sweeper as general homeowner education, last updated October 1, 2026. Sources are linked where they are cited. What applies to your home can depend on your local building code, your appliance and its manufacturer's instructions, and the actual condition of your chimney, so this guide is not a substitute for an inspection.
If you need help
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Chimney caps
Rain and animal protection at the flue top.
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Cleaning of the flue and firebox.
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Damper and cap damper repair or replacement.
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Rusted, bent or missing caps.
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Clear what moved in and keep it out.
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