Some Interesting Historical Conclusions About Parrots by Sally Blanchard When parrots from other parts of the world were being studied and imported into Europe, it could be very difficult to classify how the birds were related to each other.
To me, the most interesting classification at the time is the Grey-trunked Ara. Ara is the genus of several macaws but the bird that was labeled the Grey-trunked Ara was the Palm Cockatoo. Why was it considered to be a macaw? Despite the fact that Macaws are from Central and South America and the 'Grey-trunked Ara' was from Australia, the bird was classified as an Ara because of its bare facial patch.
In 1801, the book The Natural History of Parrots by Francois le Vaillant classified several Blue-fronted Amazons as different species because of their many differences in plumage. The Festive or Bodini's Amazon wasn't considered to be an Amazon mostly because it had a flatter head and a red patch on its rump, unlike any other Amazon.
With the Yellow-headed Amazons, the Double yellow-heads were labeled the male of the species, and the Yellow-front was considered to be the hen. The male and female Eclectus were considered to be two different species until they began to observe them mating.
These are just a few of the ways that early ornithologists and aviarists mistook what parrots were related to each other. Now with DNA studies of parrots and other birds, there have been and will be more changes in the classifications of the relationships of other birds.