There is a line that floats through cinema the way certain melodies float through jazz standards: heard, half-remembered, attributed with confidence to the wrong source. It goes, more or less, like this: there is a bird in this world that has no feet, and it can do nothing but fly, fly, fly, and when it grows tired it sleeps in the wind, and it touches the ground only once in its life, and that is the moment of its death.

Wong Kar-wai placed this image at the center of Days of Being Wild, which arrived in Hong Kong cinemas in 1990 and has been arriving in the imaginations of a certain kind of viewer ever since. Thirty-two years later, the same conceit surfaced in the Elvis Presley biopic directed by Baz Luhrmann (the man who gave us the shimmering, overcaffeinated Great Gatsby) and the echo was unmistakable. Two films separated by three decades, two entirely different traditions of cinematic excess, and yet the same bird, the same restlessness, the same inability or unwillingness to land.

I had known for some time that both films were probably drawing on an older source, but I had not troubled myself to find it. Curiosity, in my experience, follows its own calendar. It arrives when it is ready, and not before. The proximate cause of my finally looking into it was, of all things, a Chinese web novel (Reverend Insanity) in which the protagonist, Fang Yuan, departs the Skeletal Bone Mountain on the back of a footless bird. The detail struck me not as novel but as familiar in the particular way that unresolved questions are familiar: a small, nagging recognition that one has been carrying an unfinished thought.

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The trail led back, as trails of this kind often do, to a midcentury American stage production, a play from the nineteen-fifties, later adapted into a film of some reputation that I had never seen: The Fugitive Kind, starring Marlon Brando and Anna Magnani, directed by Sidney Lumet, based on Tennessee Williams’s Orpheus Descending. Williams, who was not in the habit of understating things, had put the legless bird into the mouth of a drifter, and there it had remained, waiting to be picked up by anyone who needed a metaphor for the impossibility of rest.

What surprised me was that the bird is not merely literary. It has an iconographic life, and an old one. The creature is called the Martlet, and it has appeared in European heraldry since at least the thirteenth century: on the arms of noble families, municipal seals, and, in more recent centuries, the crests of universities. The University of Houston displays three of them on its shield. The logic of the symbol, in academic contexts, is not difficult to parse: the bird that never stops flying serves as a figure for the mind that never stops seeking. It is the kind of emblem that flatters the institution adopting it, which is precisely what good heraldry is supposed to do.

The Martlet’s prototype in the natural world is the common swift, a bird whose physiology happens to underwrite the myth with an unusual degree of literalness. Swifts possess a neurological capacity for unihemispheric sleep: they can shut down one half of the brain while keeping the other alert, cycling between hemispheres, so that flight continues uninterrupted. A swift has been recorded remaining airborne for more than two hundred consecutive days. Its legs, meanwhile, are so abbreviated, so vestigial in appearance, that the uninstructed observer might reasonably conclude they are absent altogether. From this modest anatomical fact, an entire mythology of perpetual motion was constructed, and it proved remarkably durable. Seven centuries of heraldic tradition is not nothing.

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Having established this much, I found myself wanting to know whether other cultures had arrived at the same myth independently: whether the image of a creature condemned or blessed to move without ceasing was a universal intuition or a specifically European fixation. The answer, somewhat to my surprise, leaned toward the latter. The idea of eternal, compulsory flight does not appear to have captured the imagination of most civilizations. Europe, for whatever reason, found the conceit irresistible. The Flying Dutchman, that spectral vessel from maritime folklore (the ship that turns up in Pirates of the Caribbean and in Wagner and in a hundred lesser tellings) is not merely fast. It is incapable of making port. It sails and sails and never arrives. In the biological world, the closest analogue may be the bluefin tuna, which must swim continuously in order to force water across its gills. Stop, and it suffocates. Whether certain other large ram-ventilating fish share this condition is a question I have left, for the moment, to the ichthyologists.

The one significant exception I found outside Europe was Persian. In the mythology of ancient Iran, there exists a bird called the Huma, which flies ceaselessly through the sky until the day of its death and whose shadow, falling upon a person below, confers fortune, power, and wealth. The Huma appears on Achaemenid metalwork: bronze vessels, silver plates, the ceremonial objects of a court that understood the uses of symbolic animals. It is a bird whose function is benediction from a great height, which is perhaps the most flattering thing a flying creature has ever been asked to do.

In modern Iran, the Huma survives on the livery of Iran Air, where it serves as the airline’s logo, a choice that manages to be at once nationalistic and poetic, which is more than most airline branding achieves. But the grandest contemporary deployment of the image belongs, unexpectedly, to Uzbekistan, a country that shares no border with Iran. The Uzbek coat of arms is dominated by a great Huma bird with wings outspread, sheltering the nation beneath its span. The implication (divine guardianship, perpetual vigilance from above) is not subtle, but national heraldry is not typically the province of subtlety.

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The discovery that pleased me most, however, was personal, and small, and had been hiding in plain sight for years. I know several people named Humar. One of them is a cousin of mine. I had always understood the name vaguely, in the way one understands the names of people one has known since childhood: as sounds first, meanings second, if at all. Looking into it now, I found that the direct translation is not, as one might expect, “good fortune” or “blessing.” It is closer to “infatuation”: a state of being seized, overcome, entranced. The semantic range includes delight, obsession, the particular vertigo of falling under a spell.

This makes a kind of sense that the literal translation of “lucky bird” would not. The Huma does not bestow simple good luck, the way a found penny or a shooting star might. It transforms a life. Its shadow passes over you and nothing is afterward what it was. To name a child Humar is not to wish her luck but to wish her the condition of someone who has been touched by something overwhelming: a long, ecstatic pursuit that does not resolve into rest. It is, in other words, a name that carries within it the same restlessness as the bird itself: the inability, or the refusal, to come down.

I have known these people for years. It had never once occurred to me that their names were connected to a footless bird in ancient Persian mythology. One does not, as a rule, interrogate the etymology of one’s relatives. But the connection, once seen, is difficult to unsee, and it casts a faint, retrospective light over a good many ordinary conversations and family dinners, none of which were, at the time, conducted with any awareness of ornithological symbolism.

An interesting find. The kind of thing you come across when you finally follow a question you have been carrying, without quite noticing, for a very long time.