Avians were the first sapient life bug ferrets encountered on another planet, and the two couldn't be more different. Avians hail from an ocean planet that kept much of their (mostly) flying genus separate long enough to dramatically speciate. The five major recognized species of avian are skimmers, divers, pygmies, polars, and flightless. Skimmers are inarguably the most populous, their many colonialist nations having used technology to connect and subjugate their globe, afterwards moving on to their local star system.
Their advance into space was the fastest of any of the sophonts, perhaps because of their far earlier development of aircraft. A lot of their other technology has yet to catch up, with their medical technology in particular lacking due to their delicate physiology, skimmer cultural taboos about the body, and non-universal educational systems.