Large bird once seen among Jerusalem Oaks (3)
I believe the answer is:
moa
'large bird' is the definition.
(I've seen this in another clue)
'among jerusalem oaks' is the wordplay.
'among' says the answer is hidden in the clue.
'MOA' is hidden within 'jerusalem oaks'.
'once seen' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for moa that I've seen before include "Gigantic extinct bird" , "Bird no longer" , "Extinct large flightless NZ bird" , "Bird lost" , "Extinct flightless NZ_bird" .)