Animals in Your Chimney: How to Prevent and Remove Them

Chimneys are warm, sheltered, and — if uncapped — easily accessible. That makes them attractive nesting sites for a range of wildlife. Here's what you need to know about preventing animals from entering your chimney and what to do if they already have.

Common Chimney Inhabitants

Chimney swifts are small migratory birds that are federally protected under the Migratory Bird Treaty Act. They nest inside chimneys during their spring and summer migration. If chimney swifts are nesting in your chimney, you cannot legally remove them or their nest until they have migrated in the fall. The solution is to cap the chimney after they leave to prevent them from returning.

Starlings and other birds build nests of twigs, grass, and debris that can block the flue entirely. Unlike chimney swifts, these nests can be removed.

Squirrels and raccoons occasionally fall into chimneys or attempt to nest near the top. They're more common in chimneys with damaged caps or no caps at all.

The Hazards of Animal Nesting

An animal nest in the flue is more than an inconvenience. A nest can block the flue entirely, preventing combustion gases from exiting — a carbon monoxide hazard. Nesting material is also flammable. And animals that die in the flue create odor problems and can attract insects.

Prevention: The Chimney Cap

A properly installed chimney cap with mesh sides is the most effective way to prevent animals from entering the flue. The mesh openings are large enough to allow smoke to exit but small enough to block birds and mammals. This is the single best investment you can make to protect your chimney from wildlife.

What to Do If Animals Are Already Inside

If you hear scratching, chirping, or other sounds from your chimney, don't use the fireplace. Call a chimney professional to assess the situation. In most cases, the animal can be removed or will leave on its own, and the chimney can be swept and capped to prevent recurrence.

If you suspect chimney swifts, contact a local wildlife organization for guidance on the legal timeline for removal.