This is a known roosting location for Chimney Swifts. On 8/14/15, a surveyor counted 1480 swifts entering the chimney to spend the night. On this date, I recorded 1660 swifts entering. This is a rough estimate due to a large majority of the swifts waiting until it was dark to enter the chimney which made counting a challenge!
The swifts are also very hard to photograph due to their speed and unpredictable flight path.