Fine Feathered Facts
Before it was a common term for accomplishment, a “feather in your cap” was a mark of achievement in several cultures. Among them, native Americans who wore a feather for each enemy slain, medieval knights given plumes for bravery, Hungarians marking a killed enemy Turk, or hunters showing game bird feathers.
Bird feathers are hollow so as to be very light for their strength, allowing (most) birds to fly…
…and this hollowness made feathers great writing instruments in the quill / feather pen days, and still among quill pen enthusiasts. That hollow center was a natural reservoir for ink.
Tarring and feathering has been a humiliating and painful punishment since at least 1189 when Richard the Lionheart decreed it for thieves caught aboard his ships. Old fashioned tar, however, was made with pine tree sap, and was not the petroleum-based tar of the modern era. When the traditional ingredients were in short supply, syrup and cattails have also been used.
To “make feathers fly,” as in arguing, is a reference to birds (and especially chickens) losing feathers while fighting with each other. “Make/watch the fur fly” conveys the same meaning.
The term “horsefeathers” was coined just a few years before the famous Marx Brothers’ movie of that name, and means nonsense (and by some accounts refers to horse poop.)
Just as showy plumage feathers are not used for flight, a bird might have seven different types of feathers on its body, each with a different function.