This study is about songbirds and their songs but I am sure that parrots have them, too. The only thing I did not like was that they say that 'smarts' are not needed for traditions as if birds were not smart - which we all know is NOT true!
https://www.sciencedaily.com/releases/2 ... 094815.htm
As an interesting note, with song-bred canaries, at the show/contest, when they are judging their songs, any bird that sings exactly like a previous champion is automatically disqualified.