This proverb is a colorful way of describing the fact that humans with similar tastes congregate in groups, just as birds of the same species frequently form flocks and fly together. Biologists say that this “safety in numbers” behavior makes the birds less at risk of predators.
The saying has been in use since at least the mid 1500s. In 1545 William Turner used a version of it in his papist satire The Rescuing of Romish Fox: “Byrdes of on kynde and color flok and flye allwayes together.”
The current English version of the phrase first appeared in 1599, in The Dictionarie in Spanish and English, which was compiled by the English lexicographer John Minsheu.
In Benjamin Jowett’s 1856 translation of Plato’s Republic, the phrase appears thus: “Men of my age flock together; we are birds of a feather, as the old proverb says.” However, the lack of any citation of the phrase in English prior to the 1500s does tend to suggest that its literal translation wasn’t present in The Republic – a text that was widely read by English scholars of the classics well before the 1500s.
Some birds, such as starlings, fly in groups of such density as to form beautiful moving shapes, called murmurations, when seen from a distance. It used to be more common to refer to birds flying together than flocking together and many early citations use that form.
Birds flock together in the game of golf, too. Here are the names of some scores:
Birdie: A score of one under par on a hole. The story goes that the name arose in 1899, when a golfer hit his second shot only inches from the cup on a par-four hole after his first shot had struck a bird in flight.
Eagle: A score of two under par, better than a birdie, so the bird had to be bigger.
Albatross or double eagle: A score of three under par (very rare). The albatross is one of the largest birds.
Condor: unofficial name for a score of four under par, the lowest individual hole score ever made. Also known as a double albatross or a triple eagle.
I’ve never played golf, nor followed the game, but the names for the scores are much more interesting than the “overtricks” and “undertricks” in contract bridge. Perhaps I should set my imagination to starting a new trend. Birds and worms? Up two birds, down three worms?