There are a number of species who prove to be more difficult to write for on a Starfleet ship, whether it is due to what they breath, their ability to walk or their mode of communication. Yet in many cases, there are ways around those complications. Breathing apparatus, universal translator and leg brace and/or wheelchairs or even through a series of operations. Though the later tended to be still difficult to manage.
Let’s take a look one such species: the Aurelians. The only named one, within the community, is their ambassador to the Federation. They are a bipedal species, covered head-to-toe in various shades of yellow feathers given them the appearance of a bird-like people. Right down to their wings, which are awkward to maneuver throughout a standard Starfleet starship corridor. Despite the extreme case of look-alike between the avian species and birds, they have arms and legs much like that of standard humanoids, making working with any equipment simple. Just be sure to duck through doors with those wings!
Despite the number of similarities between Aurelians and your more common species, like Humans or Vulcans, there are a number of differences which make this species rather interesting. Everyone wishes to fly at some point in their life. These avian people have such capabilities, and though it is possible by all members, they are limited to how much time is spent in flight; the strain from their sheer size makes it difficult to go long distances, though gliding is still possible with ease.
Much of their history is passed-down orally, something they learn from an early age. It also is part of how they become full-fledged members of their family and flock. Not just their personal history but their world as a whole as well. One of their oldest customs is a tattooing, on their beaks, which gives them a identification of family and flock for all to see.
They have a fondness for the sciences and medicines, something that stems from their past. To find them in a militant position would be not only uniquely, but perhaps unwise. Their bone structure is weak, hollowed. And though their eyesight is strong their ears are weak. These qualities would be dangerous from someone trying to protect a group of officers or civilians. The sciences, however, tend to be just right to quench their curiosity. And their sense of community has shared all the knowledge they could amongst each other.