Whether they have any extant function or not, they have lost their former function and in that sense they do fit the definition of vestigiality. Vestigial structures are often called vestigial organs, although many of them are not actually organs.
There are quite a few birds famous for doing ritualized mating dances, so I would only list 5: The Red Capped Manakin, The Black-footed albatross, The Western and Clark's grebe, The Superb bird of Paradise, & The Victoria's riflebird.
George calls G.O.B.'s chicken dance a tweety bird dance when he performs it during a Bluth Company softball game. (Switch Hitter) G.O.B. later injures his leg when performing the chicken dance to mock Buster, so he is unable to perform it again when mocking Michael for being too afraid to pursue Sally Sitwell.