Chimney Champions is a Jacksonville, FL chimney service company staffed by CSIA certified technicians and a National Chimney Sweep Guild member. This page explains when chimney swifts leave, what federal law requires of homeowners while the birds are present, and what chimney service steps to take once they are gone. What are chimney swifts and why do they nest in chimneys? Chimney swifts (Chaetura pelagica) are migratory birds that travel from Peru to North America each spring and commonly build nests inside chimney flues. Chimney swifts use a glue-like saliva to attach small, cup-shaped twig nests directly to the interior wall of a chimney flue. The species is federally protected under the Migratory Bird Treaty Act, which makes it illegal to remove or disturb the birds or their active nests during breeding season without a Federal Migratory Bird Depredation Permit. When do chimney swifts leave the nest? Chimney swift hatchlings … Continued