Fiilestii

The Fiilestii are an avianoid predatory species native to the Alpha Quadrant, and by the 23rd century were members of the First Federation.

They evolved on a low-gravity world with dense air. 

History
Their homeworld was long since lost. Since circa 9,700 B.C, the remaining population of more than one million Fiilestii have resided in the Web of Worlds in a biome module customized for their physiology. It was spacious, airy, with kilometers-tall, spindle-like towers scattered throughout.

In 2269, Hikaru Sulu and Pavel Chekov explored the Fiilestii low-gravity module while wearing wingsuits to enable them to glide. When shifting gravitational conditions destabilized the module, the USS Enterprise (NCC-1701) helped evacuate citizens and tourists, but at least 3,600 people could not be saved.