It was the only parrot species native to the eastern United States, and the last one was killed in the wild in 1904, and the last one died in captivity in 1918. In Audubon's time, the now extinct Carolina Parrot was the only common parrot species in the United States, and he captured its likeness as shown above. And this is what he wrote about it and its food, found here:
Doubtless, kind reader, you will say, while looking at the figures of Parakeets represented in the plate, that I spared not my labour. I never do, so anxious am I to promote your pleasure.
These birds are represented feeding on the plant commonly called the Cockle-bur. It is found much too plentifully in every State west of the Alleghanies, and in still greater profusion as you advance towards the Southern Districts. It grows in every field where the soil is good. The low alluvial lands along the Ohio and Mississippi are all supplied with it. Its growth is so measured that it ripens after the crops of grain are usually secured, and in some rich old fields it grows so exceedingly close, that to make one's way through the patches of it, at this late period, is no pleasant task. The burs stick so thickly to the clothes, as to prevent a person from walking with any kind of ease. The wool of sheep is also much injured by them; the tails and manes of horses are converted into such tangled masses, that the hair has to be cut close off, by which the natural beauty of these valuable animals is impaired. To this day, no useful property has been discovered in the cockle-bur, although in time it may prove as valuable either in medicine or chemistry as many other plants that had long been considered of no importance.
Yes! This native bird feasted on those nasty cockleburs that are the bane of anyone who's hiked through brush or undergrowth in these parts. I used to have to pick them out of the shiny coat of my black labrador retriever, one by prickly one, after we'd taken long walks through the fields and woods.
Sadly, part of what contributed to the Carolina Parrots' extinction is that the flock would often fly back to the spot where one of the flock had been felled by a shot, and where of course more would be shot, as described by Audubon:
Should a person shoot at them, as they go, and wound an individual, its cries are sufficient to bring back the whole flock, when the sportsman may kill as many as he pleases.
I'm so thankful that at least Audubon got to see them, describe and depict them for us so that we can at least imagine what it might've been like to catch a flash of bright yellow, green and red in the trees as we hiked down the Eno River. Still makes me angry that they are gone forever.