Confused rat breeds with bird! (9)
I believe the answer is:
redbreast
'bird' is the definition.
(redbreast is a kind of bird)
'confused rat breeds' is the wordplay.
'confused' indicates an anagram.
'rat'+'breeds'='ratbreeds'
'ratbreeds' is an anagram of 'REDBREAST'.
'with' acts as a link.
(Other definitions for redbreast that I've seen before include "Type of robin" , "One tweets" , "Flapper" , "Bird" .)