Whooping birds (6)
I believe the answer is:
cranes
'whooping birds' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for cranes that I've seen before include "demoiselles" , "Wading birds with long legs and necks" , "Lifting machines and wading birds" , "Long-legged birds or heavy lifting machines" , "Long-necked wading birds" .)