Listener firstly taking bird made of baked clay (7)
I believe the answer is:
earthen
'made of baked clay' is the definition.
(I've seen this in another clue)
'listener firstly taking bird' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'firstly' says to take the initial letters.
'bird' becomes 'hen' (hen is a kind of bird).
The initial letter of 'taking' is 't'.
'ear'+'t'+'hen'='EARTHEN'
(Other definitions for earthen that I've seen before include "Made of baked or fired clay" , "Made of baked clay, perhaps ware" , "that's thrown in clay" , "(Of a pot) made of fired clay" , "Like many pots" .)