Squirrel's nest (4)
I believe the answer is:
drey
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">squirrel's nest</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for drey that I've seen before include "A squirrel's tree nest" , "Nest of a squirrel" .)