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