Puffin, for one (3)
I believe the answer is:
auk
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">puffin for one</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 auk that I've seen before include "Black/white northern diver" , "Short-winged seabird" , "Northern sea bird with short narrow wings" , "Black-and-white diving bird of northern seas" , "Northern seabird with small narrow wings" .)