Brown songbird (6)
I believe the answer is:
thrush
'brown songbird' is the definition.
(I've seen this in another clue)
This is the entire clue.
(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" .)