Ornithologists have discovered a 2,500-year-old Gyrfalcon nest in a cliff in Greenland:
"The nesting site is still continually used by gyrfalcons, the
world's largest species of falcon, and is the oldest raptor nest ever
recorded.Three other nests, each over 1,000 years old, have
also been found, one of which contains feathers from a bird that lived
more than 600 years ago."
The thousand-year-old one appears to be still in use as well:
Hawk Swoops into Birdie's Restaurant in NYC [tr]