Feathers were produced by bird species, such as crows and ravens, for protection, display, and flight. Humans also used feathers for various purposes.
Deputy Sheriff Bennings, a Human descendant on the Skagaran colony, decorated his hat with a few black feathers. (ENT: "North Star").
Romulan Birds-of-Prey had a bold pattern of an alien bird's feathers painted on the ship's ventral hull when the USS Enterprise encountered one in 2266 near the Romulan Neutral Zone. (TOS: "Balance of Terror")
Sylvia used the phrase "like feathers in the wind" to describe a group of helpless aliens after Kirk had smashed her transmuter. (TOS: "Catspaw")
A stuffed, bird-like creature Trelane had in his mansion was covered in feathers. (TOS: "The Squire of Gothos")
The Aurelians were a bipedal, relatively tall, ornithoid race that had bright yellow feathers. (TAS: "Yesteryear")
Feathers could also be found on the body of Quetzalcoatl, who was a feathered-serpent deity worshiped in Mesoamerica and was usually associated with or equated to Kukulkan. (TAS: "How Sharper Than a Serpent's Tooth")
The Skorr were an ornithoid race with what appeared to be feathered wings. (TAS: "The Jihad")
When recreating an 18th century French military scenario on a planetoid in 2364, Q also created a marshal's tent for himself with candles, lamps, furniture, and feathers with ink for writing. (TNG: "Hide And Q")
When Deanna Troi brought a local costume from Angel I for William T. Riker and asked if he was "going to put that thing on and parade around like one of them," Riker responded by telling her that he had been required to wear feathers on Armus IX, as well as having had to wear furs on Kabatris. (TNG: "Angel One")
One of multiple holographic opponents in Worf's Klingon calisthenics program was covered in feathers. (TNG: "The Emissary")
Jean-Luc Picard was given a hat with a feather in it when Q put the crew of the USS Enterprise-D into a situation where they became Robin Hood and his Merry Men. (TNG: "Qpid")
The tympanic tickle is likely a type of sexual act Ferengi can perform on one another, where the tympanic membrane was stimulated with the help of a feather. When performed by an amateur, the feather can get stuck and medical attention was needed to remove it. (DS9: "Afterimage")
The game of darts appealed to Miles O'Brien because, as he told Quark, it involved "No lasers, no holograms; just steel tips and feathers." (DS9: "Visionary")
A dream catcher was often decorated with feathers. (VOY: "Human Error")
In 2374, after Seven of Nine abruptly left USS Voyager, Janeway found a passage in Seven's logs reading, "The feathers are black… wingspan approximately one and a half meters… the eyes are yellow…" (VOY: "The Raven")
When Harry Kim and B'Elanna Torres found themselves in Viorsa's virtual reality program, a Little Woman brushed Kim's head with a feather duster in a mock-ceremonial manner. (VOY: "The Thaw")
The Banea had distinctive forehead ridges similar to the combs of some species of Earth birds, and feather-like structures around their faces and on their brows. (VOY: "Ex Post Facto")
The hull of the Valdore-type was marked by distinctive "feather"-shaped plating. (Star Trek Nemesis)
Penguin feathers were mentioned in the final draft script of TOS: "Charlie X"; an ultimately unused line of dialogue in that teleplay featured Doctor McCoy jokingly agreeing to give Charles Evans some "voodoo and superstition lessons" if Evans brought his own "chicken's teeth and penguin feathers."
A Vulcan statue, featured in the Star Trek: Enterprise episode "Home", holds a feather in its right hand. This item was sold off on the It's A Wrap! sale and auction on eBay. [1](X)
According to AT: "Context Is for Kings", Sylvia Tilly's pillows, which couldn't be made of polyester and viscoelastic polyurethane foam, were down instead.