Possible causes, not a remote diagnosis
Birds may be nesting or roosting; other animals or loose components can also make noises. A sound recording does not establish which species is present.
What to document safely
Note the timing and type of noise and any activity visible from the ground. Keep pets away and avoid reaching into the fireplace or trying to trap animals.
Keep the appliance model, fuel, previous report and date of last service together. A clear sequence of events can be more useful than deciding in advance which component must be replaced.
Your next service conversation
Leave the system unused and contact an appropriate chimney or wildlife professional. Do not smoke animals out or close an occupied opening. The Fish & Wildlife Service explains chimney swift protections.
Animal activity and chimney blockage assessment →Can a sweep remove every bird nest immediately?
No. Species and legal protections matter. Ask for wildlife guidance before disturbing birds, eggs or nests; work may need to wait.
Ask for evidence before approving repairs
Request a report that distinguishes what was observed from what remains uncertain. Ask the company to identify any area it could not inspect and whether another trade is needed. If a major repair is proposed, compare a second written scope using the same appliance details and findings.
Do not treat a directory profile, an estimate or this page as clearance to use an appliance. Ask the attending professional what must be resolved before reuse.
Read the detailed guide and its sourcesTake the service question to your location
Use the local guide to prepare questions about access, building history and the authority responsible for your address. The service brief is national guidance; local permits and current burn restrictions must be checked separately.