Cherry that is rising? Duck! (5)
I believe the answer is:
eider
'duck' is the definition.
(eider duck is a kind of duck)
'cherry that is rising?' is the wordplay.
'cherry' becomes 'red' (synonyms).
'that is' becomes 'i.e.' (synonyms).
'rising?' says the letters should be written in reverse (going up in a down clue).
'red'+'ie'='redie'
'redie' in reverse letter order is 'EIDER'.
(Other definitions for eider that I've seen before include "Reed I make into a duck" , "Quilt- furnishing duck" , "Duck valued for its fine soft down" , "Northern sea duck" , "Source of fine soft down" .)