An aviary was a large enclosed structure for keeping birds.
Starbase 25 had an aviary that housed various species of ornithoids, as well as treehouse residences for Aurelians. The domed roof of the structure was comprised of holographic panels that projected the illusion of an open sky. Beckett Mariner once had a date there.
In 2381, Mariner and Brad Boimler crashed their kart into the aviary while pursued by station security, and ended up flipping themselves into a stream. (LD: "An Embarrassment Of Dooplers")