Harper noticed that Bartram's notes were considerably altered and expanded in the printed edition, and the detail of the white tail appeared in print for the first time in this revised account. Harper believed that Bartram could have tried to fill in details of the bird from memory and got the tail coloration wrong. Harper and several other researchers have attempted to prove the former existence of the king vulture, or a close relative, in Florida at this late date, suggesting that the population was in the process of extinction and finally disappeared during a cold spell. Additionally, William McAtee, noting the tendency of birds to form Floridian subspecies, suggested that the white tail could be a sign that the painted vulture was a subspecies of the king vulture.