Animals left one bit of pretty flower (7)
I believe the answer is:
cowslip
'flower' is the definition.
(I've seen this before)
'animals left one bit of pretty' is the wordplay.
'animals' becomes 'cows' (cow is a kind of animal).
'left one' becomes 'li' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'bit of' says to take the initial letters.
The first letter of 'pretty' is 'p'.
'cows'+'li'+'p'='COWSLIP'
Can you help me to learn more?
(Other definitions for cowslip that I've seen before include "Wild flower of primrose family" , "Early spring flower" , "Type of primrose" , "Wild yellow primula" , "Wild spring flower" .)