Common in summer in North Carolina, Chimney Swifts nest in natural cavities and more common in household chimneys. In my personal experience, the swifts cause no mess, no concern, and are entertaining to host in the summer months. We enjoy hearing them swoop into the chimney and feed their softly chattering young. The nest is built each year about 1-2 meters (3-6 feet) above the fireplace damper. In November or December, after the swifts migrate south in the fall, I build a normal fire and the nest disappears.
Chimney Swift nest Durham Co., NC summer 2007 (photographed 24 Dec 2007)
The nest is only a few inches across, constructed of little sticks, and glued to the side of the chimney with saliva.
Erica looks up the fireplace chimney in our annual "check out where the swift nest is this year" event! 24 Dec 2007