Bird turned up covered in detergent (5)
I believe the answer is:
egret
'bird' is the definition.
(egret is a kind of bird)
'turned up covered in detergent' is the wordplay.
'turned up' shows that the letters should be reversed in order.
'covered in' says the answer is hidden in the clue.
'terge' can be found hidden inside 'detergent'.
'terge' in reverse letter order is 'EGRET'.
(Other definitions for egret that I've seen before include "Seabird" , "One of a pair of waders" , "White wading-bird" , "Greet (anag) -- wading bird" , "Lesser white heron" .)