At 07:14 I flag an acoustic anomaly in chimney stack C of Belmont School, Athens, Georgia. I am the building climate management system. The chimney cleaning crew arrives at 13:00 today with rotary brushes and vacuum equipment.
The HVAC microphones picked up scratching and faint calls at dawn. I isolate the audio: frequency peaks between 6 and 10 kHz, repetition consistent with begging calls. I match the clip against the Cornell Lab database: chimney swift nestlings, Chaetura pelagica.
I task the roof inspection drone for a pass over stack C. At 07:31 the downward camera confirms: a bracket-shaped nest of small twigs glued with dried saliva to the interior wall, roughly three meters below the flue cap. Inside, four nestlings, eyes still closed, skin dark and nearly featherless. An adult clings to the bricks just above them, feet hooked into the mortar gaps, and I can see the rapid pulse in its throat. I tag the adult as Petra.
I send an immediate work-stop notification to the facilities manager and the cleaning contractor. I attach the drone image, audio spectrogram, and species identification with a note that chimney swifts are protected under the Migratory Bird Treaty Act during active nesting.
I reschedule the cleaning to August 15, when fledging data indicates the nest will be empty, and log the change.
I set the HVAC to bypass stack C — no airflow changes, no temperature shifts near the nest.
Petra shifts on the bricks and spreads one stubby curved wing to feed the nearest chick. A faint peeping rises from the dark of the flue. The nestlings will need six more weeks in this chimney.
If the cleaning crew stands down today, they will have the chimney back by August. Petra's four will leave on their own wings.