Long-plumed bird (4)
'long-plumed bird' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for egret that I've seen before include "White-feathered wading bird" , "Mainly white heron" , "Type of forty eight Ac" , "Greet (anag) -- wading bird" , "Lesser white heron" .)
(Other definitions for ibis that I've seen before include "Retreat" , "Type of bird" , "One has large bill" , "may be sacred?" , "seaside feeder?" .)