Brown songbird (6)
I believe the answer is:
thrush
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">brown songbird</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 thrush that I've seen before include "Bird - fungal disease" , "Songster" , "Infection of the mouth and throat" , "Bird that sings" , "Small bird - fungal mouth infection" .)