A rare bird is someone or something out of the ordinary, a person, object or occurrence so unusual that it stands apart from everything around it. It is most often used of people, usually with a touch of admiration, to describe someone whose character, skill or combination of qualities is hard to find elsewhere. It can also be used more neutrally, of anything that turns up only occasionally and is worth remarking on when it does.
What’s the origin of the phrase ‘rare bird’?
The phrase is an English translation of the Latin rara avis, and the Latin itself comes from the Roman satirist Juvenal. In his Satire VI he describes the ideal wife, the sort of woman with every quality a husband could want, as a bird rare on earth and similar to a black swan. At the time Juvenal was writing, in the late first and early second centuries, Romans believed that all swans were white, so comparing something to a black swan was not just a way of calling it rare but of suggesting it might not exist at all.
The Latin phrase rara avis was taken into English use from around 1600, but for a long time it was kept in its original Latin form rather than translated. According to Dictionary.com, English writers only began rendering it as “rare bird” in the late 1800s, and it is generally used as a compliment. Wiktionary disagrees, saying the English version, rare bird, is attested earlier than the borrowed Latin form, so which of the two reached English first is not settled. Both phrases have continued in use side by side ever since, with rare bird becoming the more everyday English choice and rara avis surviving as a more bookish alternative, particularly in writing that wants to signal a classical flourish. The underlying image, of something as improbable as a black swan, has long since faded from most speakers’ minds, but the sense of exceptional, hard-to-find rarity it was built to express has stayed intact.