Bird taken by cunning without haste (6)
I believe the answer is:
slowly
'without haste' is the definition.
Both the answer and definition are adverbs. Perhaps you can see an association between them that I can't see?
'bird taken by cunning' is the wordplay.
'bird' becomes 'owl' (owl is a kind of bird).
'taken by' is an insertion indicator.
'cunning' becomes 'sly' (synonyms).
'owl' going into 'sly' is 'SLOWLY'.
Can you help me to learn more?
(Other definitions for slowly that I've seen before include "Not quickly" , "At less than normal speed" , "Little by little" , "Not so fast" , "Lento, in music" .)