Arachnids!
Once again spiders have woven webs across the camera dome. Riverfront Plaza (the building that this nest box is located atop) is adjacent to the James River, meaning there are plenty of flying insects around. The plentiful insects, along with the many nooks and crannies of the ledge make for great spider habitat!
Biologists only access the nest ledge for necessary managment activities. The next time they’re out there they’ll take a moment and clean the camera dome.