Birds half-destroyed purple plant (8)
I believe the answer is:
larkspur
'plant' is the definition.
The answer is an example.
'birds half-destroyed purple' is the wordplay.
'birds' becomes 'larks' (lark is a kind of bird).
'half destroyed' suggests halving the letters.
'purple' halved is 'pur'.
'larks'+'pur'='LARKSPUR'
(Other definitions for larkspur that I've seen before include "Garden flower of delphinium family" , "Mediterranean plant of the buttercup family" , "Delphinium-like flower" , "Plant with flower spikes" , "in bed!" .)