Cat and a bird endlessly going round tree (8)
I believe the answer is:
bergamot
'tree' is the definition.
(bergamot is a kind of tree)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for bergamot that I've seen before include "Something extracted from orange" , "Variety of pear" , "Flavouring in Earl Grey tea" , "perfume" , "Fine pear" .)