Fake little bird? Don't worry any more! (6,2)
I believe the answer is:
forget it
'don't worry any more' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'fake little bird?' is the wordplay.
'fake' becomes 'forge' (synonyms).
'little bird?' becomes 'tit' (I've seen this in another clue).
'forge'+'tit'='FORGET IT'
Can you help me to learn more?
(Other definitions for forget it that I've seen before include "Not a chance" , "ignore something" , "There's no need for apologies" , "Let it go!" , "Think no more of the matter" .)