Strangely chose to release small parrot (4)
I believe the answer is:
echo
'parrot' is the definition.
(both can mean to imitate or copy)
'strangely chose to release small' is the wordplay.
'strangely' indicates an anagram.
'to release' indicates named letters should be taken away (letters are released or freed).
'small' becomes 's' (abbreviation - e.g. clothes size).
'chose' with 's' taken away is 'choe'.
'choe' with letters rearranged gives 'ECHO'.
(Other definitions for echo that I've seen before include "Reflect sound" , "Greek nymph, spurned by Narcissus, who pined away until only her voice remained" , "Sound heard before" , "from Brussels?" , "Let's hear it again for the Greek nymph who loved Narcissus in vain" .)