Whilst several of the groups here classed as orders, because ornithologists have not yet agreed how they are to be arranged in larger divisions, are really of subordinal rank, the Parrots by general consent stand apart from all other birds, and undoubtedly form an Order by themselves: distinguished by opisthocoalous dorsal vertebras, combined with aygodactyle feet, and by the upper mandible being loosely articulated to the skull, so as to be moveable. The bill is short, stout, and strongly hooked. The palate is desmognathous. There is a distinct fleshy cere at the base of the bill, as in Birds of Prey. The tongue is thick and fleshy. The deep plantar tendons are galline, as in Coccyges. The ambiens muscle is variable, and so are the carotids. The furcula is weak and sometimes incomplete. There are no caeca, and the gall-bladder is generally wanting.
The feathers are furnished with an aftershaft; the spinal feather-tract is well defined on the heck' and forked on the upper back. The oil-gland is usually present and tufted, but is wanting in a few genera. There are twelve tail-feathers except in the Papuan Oreopsittacus, which has 14. Primaries 10.
All Parrots lay white eggs in a hole, generally excavated by the parent birds, in the trunk or a branch of a tree. There is no nest, the eggs being laid on the wood. Some species, occasionally at all events, make use of hollows not excavated by themselves. The young are hatched naked, and the feathers remain in the sheaths until the birds are nearly full-grown.
The Parrots have been very variously divided by different ornithologists, and Garrod (P. Z. S. 1874, p. 594) made the common Indian genus Palaeornis the type of a family. But generally Palaeornis has been classed in the same family with Psittacus, and this is the arrangement adopted by Salvadori in the British Museum Catalogue. Only three genera are found within Indian limits, and these all belong to one family and subfamily.