A blackbird in Catania (3)
I believe the answer is:
ani
'a blackbird' is the definition.
(I've seen this in another clue)
'in catania' is the wordplay.
'in' indicates a hidden word.
'ANI' can be found hidden inside 'catania'.
(Other definitions for ani that I've seen before include "Black cuckoo" , "Tropical bird" , "Indigo dye." , "One winged" , "Bird of the cuckoo family" .)