The International Ornithological Committee (IOC) recognizes these three subspecies:[4] The American Ornithological Society (AOS) and the Clements taxonomy recognize a fourth subspecies, P. m. alticola ("Chapman's parakeet"), that Arndt (2006) had suggested as a separate species.

[10][11][12][9] Agnolin (2009) called into question the validity of P. m. tucumanus, and BirdLife International's Handbook of the Birds of the World (HBW) does not recognize it or P. m. alticola, assigning only P. m. chlorogenys and P. m. mitratus to the mitred parakeet.

Adults of all subspecies are mostly green with a purplish forehead and a variable amount and pattern of red on the face.

[15][16] The differences in plumage coloration noted in the field and in specimens are possibly due to erroneous age assignments, and might also be clinal.

[11][15] The nominate subspecies P. m. mitratus of the mitred parakeet is found from the departments of Ayacucho and Cuzco in Peru south through Bolivia into northwestern Argentina as far as Córdoba Province.

Subspecies P. m. chlorogenys is found on the eastern slope of the Peruvian Andes between Amazonas and Junín departments.

[5] Populations in California, Florida, and Hawaii are apparently derived from escaped or released cage birds.

[19][7] The mitred parakeet makes some movements in response to food availability and also apparently roams outside the breeding season.

[15][9][23] The mitred parakeet's diet in its native range has not been fully described but is known to include berries and other fruits, seeds, nuts, and maize.

[19][7] The subspecies seen in American aviculture is Psittacara m. mitrata (though this is labelled with some uncertainty considering the recent developments in the taxonomy).

They make great pets for people who will devote their time and money and will understand the birds natural behaviors; screaming, biting, splashing, etc.