Two additional species have been assigned to its genus (N. francicus and N. borbonicus), based on descriptions of parrots from the other Mascarene islands, but their identities and validity have been debated.

By the time it was discovered, it frequented and nested on islets off southern Rodrigues, where introduced rats were absent, and fed on the seeds of the shrub Fernelia buxifolia.

Birds thought to be the Rodrigues parrot were first mentioned by the French traveler François Leguat in his 1708 memoir, A New Voyage to the East Indies.

[8][9] After receiving a more complete upper and lower beak which he thought showed the bird to be close to the parrot genus Palaeornis, Milne-Edwards moved the species to its own genus Necropsittacus in 1873; the name is derived from the Greek words nekros, which means dead, and psittakos, parrot, in reference to the bird being extinct.

[7] In 1879 the German ornithologist Albert Günther and E. Newton described more fossils of the Rodrigues parrot, including a skull and limb bones.

[13] Many endemic Mascarene birds, including the dodo, are derived from South Asian ancestors, and the British ecologist Anthony S. Cheke and Hume have proposed that this may be the case for all the parrots there as well.

[7] The Psittaculini may have invaded the area several times, as many of the species were so specialised that they may have evolved significantly on hotspot islands before the Mascarenes emerged from the sea.

[2] The British zoologist Walther Rothschild assigned two hypothetical parrot species from the other Mascarene Islands to the genus Necropsittacus; N. francicus in 1905 and N. borbonicus in 1907.

The Japanese ornithologist Masauji Hachisuka recognised N. borbonicus in 1953, and published a restoration of it with the colouration described by Dubois and the body-plan of the Rodrigues parrot.

[7][19][20] In 1987, Cheke found the described colour-pattern of N. borbonicus remiscent of Psittacula parrots, but considered N. francicus to be based on confused reports.

Hume added that if Dubois's description of N. borbonicus was based on a parrot endemic to Réunion, it may have been derived from the Alexandrine parakeet, which has a similar colouration, apart from the red tail.

The pectoral and pelvic bones were similar in size to those of the New Zealand kaka, and it may have looked like the great-billed parrot in life, but with a larger head and tail.

No features of the skull suggest it had a crest like the broad-billed parrot, and there is not enough fossil evidence to determine whether it had pronounced sexual dimorphism.

[12] Tafforet's 1726 description is the only detailed account of the Rodrigues parrot in life: The largest are larger than a pigeon, and have a tail very long, the head large as well as the beak.

[7]Tafforet also mentioned that the parrots ate the seeds of the shrub Fernelia buxifolia ("bois de buis"), which is endangered today, but was common all over Rodrigues and nearby islets during his visit.

Leguat mentioned that the parrots of the island ate the nuts of the tree Cassine orientalis ("bois d'olive").

[7]Pingré indicated in 1671 that local species were popular game, and found that the Rodrigues parrot was rare: The perruche [Newton's parakeet] seemed to me much more delicate [than the flying-fox].