The Bird or The Giant Bird was a dance-based character invented by William Welles during a party at Milbank 12. He would jump up and down and flap his 'wings' to a rhythmic 'Caw, Caw, Caw, Caw.' He also liked to get into people's faces. He really liked fun and music and having a goodtime. Though I don't think anyone really understood him.
The bird is not to be confused with William Welles' impression of a ghost which amuses Rachel Richardson even in memory.