Beat it with a flier! (5)
I believe the answer is:
pipit
'a flier' is the definition.
(pipit is a kind of birdanimal)
'beat it' is the wordplay.
'beat' becomes 'pip' (pipping is a kind of beating).
'pip'+'it'='PIPIT'
'with' acts as a link.
(Other definitions for pipit that I've seen before include "Lark-like bird" , "Bird related to wagtail" , "Small bird of rock or meadow" , "Songbird with streaky brown plumage" , "Songbird of rock or meadow" .)