Uncle, a raw beginner with birds (5)
I believe the answer is:
remus
'uncle' is the definition.
(I've seen this before)
'a raw beginner with birds' is the wordplay.
'beginner' suggests taking the first letters.
'with' is a charade indicator (letters next to each other).
'birds' becomes 'emus' (emu is a kind of bird).
The initial letter of 'raw' is 'r'.
'r'+'emus'='REMUS'
(Other definitions for remus that I've seen before include "doomed wolf-suckling" , "J. C. Harris's storyteller Uncle" , "partner in City foundation" , "twin brother" , "Brother of 24 across" .)