Bird gripping bunny's tail, a scavenger (5)
I believe the answer is:
hyena
'scavenger' is the definition.
(I've seen this before)
'bird gripping bunny's tail a' is the wordplay.
'bird' becomes 'hen' (hen is a kind of bird**).
'gripping' indicates putting letters inside.
'tail' says to take the final letters.
The last letter of 'bunny' is 'y'.
'hen' placed around 'y' is 'hyen'.
'hyen'+'a'='HYENA'
(Other definitions for hyena that I've seen before include "Spotted scavenger" , "Carrion-eating mammal" , "Dog-like animal with howl like laughter" , "Dog-like carrion eater" , "Wild animal" .)