Downy duck (5)
I believe the answer is:
eider
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">downy duck</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for eider that I've seen before include "Species of duck" , "Type of duck" , "Breed of duck" , "Down comes from this" , "Duck noted for down" .)