Enclosure for birds (6)
I believe the answer is:
aviary
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">enclosure for birds</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for aviary that I've seen before include "Cut gem; small film part" , "Where flights are limited" , "Bird house" , "Bird-house" , "Its inhabitants probably like flying" .)