Old gold coins (6)
There are a few possibilities for this:
doubloons
(Other definitions for eagles that I've seen before include "Great birds in eyries" , "band" , "Such raptors" , "Keen-eyed birds" , "rock group?" .)
'old gold coins' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ducats that I've seen before include "pieces of old" , "Old gold coins" , "Shylock lost" , "money" .)