Alpine ptarmigans a bit silly (5)
I believe the answer is:
inept
'silly' is the definition.
(I've seen this before)
'alpine ptarmigans a bit' is the wordplay.
'a bit' indicates a hidden word (the answer is formed by a bit of the clue).
'INEPT' is hidden within 'alpine ptarmigans'.
(Other definitions for inept that I've seen before include "Futile" , "Clumsy, out of place" , "Lousy" , "rubbish" , "Awkward, showing no skill" .)