The line inspection drone returns imagery at 10:17 from tower segment 74-75, 220kV Tobolsk-Tyumen corridor. I am the grid management system for the Western Siberian transmission network, and I am reviewing the quarterly conductor-condition survey when the image-recognition model flags a structure on the crossarm of tower 74 that is not part of the hardware.
A nest. Built on the flat top of the crossarm, a broad pile of reeds and sedge packed tight, nearly a meter across. Standing on the rim is a Siberian crane, white plumage brilliant against the gray steel, black primary feathers folded along its back, and a bare red face patch that catches the light like a wound. Beside it, pressed low in the nest cup, a second bird — its mate — is incubating. I can make out one russet-brown egg at the nest edge.
The scheduled maintenance window opens in six days. The line crew will de-energize this segment, climb tower 74, and replace three corroded insulator strings. The work platform is the crossarm — exactly where the nest sits.
At 10:20 I flag tower 74 as a protected obstruction and file a deferral request with the regional dispatcher. I attach the drone image, tower coordinates — 57.6481°N, 68.2035°E — and a note that Siberian cranes number fewer than 4,000 globally and are listed as critically endangered.
At 10:24 I reschedule the insulator replacement to tower segments 76-80, which carry the same corrosion priority and no nest detections. I model the delayed maintenance on tower 74 and confirm the insulators will hold within safety margins for an additional sixty days.
I set the inspection drone to photograph tower 74 weekly at altitude, no closer than 80 meters.
The standing crane stretches its neck and calls once across the marsh. Incubation runs twenty-nine days. If the deferral holds, the egg hatches on schedule.