Matt Walker of BBC Earth News has an article about how gyrfalcons have continuously used the same nests for thousands of years "2,500-year-old bird's nest found".
It's carbon dating of nest contents, which has also been applied in broader contexts to rookeries:
By carbon dating solidified stomach contents, peat moss deposits and bone and feather samples from various moulting sites, researchers have in the past shown that colonies of snow petrel have returned to the same sites for 34,000 years and adelie penguins for 44,000 years.
That's pretty impressive.