Long-legged long-necked wading bird (5)
I believe the answer is:
heron
'long-legged long-necked wading bird' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for heron that I've seen before include "flier" , "Large British wading bird" , "Wader" , "eg Egret" , "Grey or white long-legged wading bird" .)