Natural ability of a quiet little bird you'd picked up (8)
I believe the answer is:
aptitude
'natural ability' is the definition.
(I've seen this before)
'a quiet little bird you'd picked up' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'little bird' becomes 'tit' (I've seen this in another clue).
'you'd' becomes 'edu' (I am not sure about this - if you are sure you should believe this answer much more).
'picked up' says the letters should be written in reverse.
'edu' backwards is 'ude'.
'a'+'p'+'tit'+'ude'='APTITUDE'
'of' is the link.
Can you help me to learn more?
(Other definitions for aptitude that I've seen before include "fitness" , "capacity" , "A natural talent or skill, for which there may be a test" , "Natural ability or skill" , "A particular talent or facility" .)