Most likely, if you heard sounds in your chimney this spring, your chimney was a home for chimney swifts. Chimney Swifts build their nests by attaching small twigs to the chimney wall with their glue-like saliva. When completed, the shallow half-cup nest protrudes two to three inches from the wall.

Chimney Swifts are protected by Federal Law under the Migratory Bird Treaty Act. Unfortunately, some chimney cleaning companies will still illegally remove active nests. When hiring a professional chimney cleaning company, be careful to select one that is reputable. Always keep in mind that “Bird Removal” is a blatant violation of the state and federal laws that protect Chimney Swifts and other migratory birds. Homeowners should inquire about a company’s policy regarding Chimney Swifts. Any company that offers or advertises such a service should be avoided. After the baby swifts have left the nest with their parents, Blackburns Chimney Sweep recommends having your chimney swept and evaluated. We also recommend capping the chimney flue if you don’t want to continue providing a home for the swifts. Caps also serve to prevent other animals from nesting and help prevent water damage.

Source:
Chimney Swifts: America’s Mysterious Birds above the Fireplace, Paul D. Kyle and Georgean Z. Kyle, Illustrated by Georgean Z. Kyle, Photography by Paul D. Kyle