In a certain code language, if 'owl' is known as 'peacock', 'peacock' is known as 'cuckoo', 'cuckoo' is known as 'pigeon', and 'pigeon' is known as 'sparrow', then what would be the name of the bird that sings well?

Pigeon

THE LOGIC FOLLOWED HERE IS :

 CUCKOO IS THE GIRL BIRD THAT SINGS WELL

AND 

ACC. TO QUESTION CUCKOO IS CALLED PIGEON