Hworill are warm-blooded, winged, only ever native to light gravity worlds with comparatively dense atmospheres, although they thrive in space habitats. There is a Hworill subspecies, 'Downies', that are adapted to colder worlds.
Hworill tend to be about a meter high when full grown, with a mass of only about 40kg. The regular Hworill sport a wide range of colors and most have brilliant crests. The Downies are considered unfortunate in that they invariably have pale, lightly patterned feathers, and no crests. The Downies, in their turn, tend to be rather scornful of the 'common' Hworill's flamboyance.
Hworill are a bisexual species with three different sexes, one female, and two male. Each of the two kinds of males can only produce either females, or more males of the same type as themselves. On some planets, and in some societies, only one or the other kind of male exists, but most Hworill societies include all three sexes. The social dynamics tend to get even more convoluted than that of human societies.
Hworill young hatch out of eggs, and require a great deal of care when young, much like humans. Physically, they grow more quickly, reaching their full adult size in half the time it takes the average human, although they usually do not gain their adult coloration until later.