Chimney swifts in your chimney
If you hear chattering or twittering inside the chimney in summer, you almost certainly have chimney swifts: small birds that nest inside chimneys and are protected by federal law. The good news is that they leave on their own.
On this page
What the law says
Chimney swifts are protected under the federal Migratory Bird Treaty Act. Texas Parks and Wildlife says it is illegal to disturb swifts or their nests during the breeding season. That means a sweep can't legally pull an active nest, and neither can you. A company that offers to is offering something it should not.
How long until they leave
Young swifts leave the chimney about 30 days after hatching. The loud chattering is the last two weeks before they go. Swifts are only here for the warm part of the year and migrate south in the fall, so by the time San Antonio's fireplace season starts they are long gone.
TPWD's guidance for sweeps is to delay cleaning at least 6 weeks for a chimney with eggs and at least 4 weeks for one with young, and that late fall, after the swifts have gone south, is the better time to clean.
What to do in the meantime
- Close the damper. Texas Parks and Wildlife advises closing the damper or otherwise sealing the bottom of the flue while leaving the top open for the birds.
- Insulate below the damper, a folded blanket or a piece of foam board in the firebox, to muffle the sound.
- If a young bird falls below the damper, TPWD's guidance for sweeps is to set a fully feathered one on the wall above the damper so it can climb back up, and report young or injured birds to local wildlife authorities.
- Leave a small nest alone. TPWD says swift nests are small and are not a safety or health hazard in a properly maintained chimney.
Plan the year around them
The easy rhythm in San Antonio: sweep in late fall after the swifts are gone and before the first norther, burn through the winter, and if you want them out for good, cap the chimney in early spring before they return. If you would rather keep them, many people do; leave the chimney uncapped and keep the damper closed in summer.
Questions San Antonio homeowners ask
Can I remove birds from my chimney in Texas?
Not chimney swifts during nesting season. They are protected under the federal Migratory Bird Treaty Act. Wait until they leave, then cap the chimney if you want to keep them out.
When do chimney swifts leave?
Young swifts fledge about 30 days after hatching, and the birds migrate south in the fall.
Are chimney swifts dangerous?
Texas Parks and Wildlife says their nests are small and pose no safety or health hazard in a properly maintained chimney. Get the chimney swept after they leave.