Whistle a little Mozart to a starling in a cage. If it knows humans as creatures that sing and are sung to, the bird will shut its beak. It will arch its starling neck, bending toward your puckered lips. It might bob its dark head back and forth at the line you’ve sent out—the dotted pops of “Papagena, Papageno” or the crystalline shards of the Adagio and Rondo for Glass Harmonica. Though a caged starling is chatty during the day and downright garrulous at night, the moment it locks in on your Mozartean whistle the little bird will only blink, aiming its entire soundless self toward the music coming from you. Note how it nods along with your tuneful body as if to say, Yes, yes, I have it.

But a starling is no parrot. Do not expect that when you whistle “Twinkle, twinkle” you’ll hear a “little star” immediately in return. You’ll have to come back whistling for a day or a week, confirming the sound’s place in the world where the bird perches. And when it does spit back whatever Mozart you’ve fed it, it will be on a starling’s zany terms: a theme from the “Haffner” Symphony punctuated with guttural warbles, or the famous Adagio from his Clarinet Concerto mixed into an uncanny interpretation of your dishwasher. The “Queen of the Night” aria sung in a screech worthy of a Bee Gee.

A few days after that, your line of Mozart will come from the birdcage as a barely recognizable string of filched sounds, all sung together in a line so arrhythmic it’s catchy. You’ll hear Mozart, your own voice, the white noise of the house you live in, plus the recesses of starling instinct: TWINK-LE—bizeeet!—TWINK—“hi! how are you!”—[doorbell]—chackerchackerchackerchacker—LIT-TLE—bweet! bweet! Purrrup!—LIT-TLE—[clanging smoke alarm]—LIT—“hi! how are you”—TLE, TWIN-KLE, LIT-TLE—[that Bee Gee screech]—STAAAAAAR!

This will then be repeated with the maddening obsessiveness of an electronica concert.

We’re not sure why starlings engage in such behavior, but we think it’s because this breed is hardwired to sing to its tribes. There are many in a starling’s life: the little tribe of the monogamous pair, that of the clutch family, the flock in the field, the mob coming home from the neighboring fields to roost together overnight. All these tribes are sonic. The male starling sings his long coupling song to his mate while she pecks for food. A young starling sends mad chatter to her close-by kin to feel where the safe world starts and stops. A wizened starling finds his place in the mob by singing long runs of mashed-up noise that prove his vast experience.

This sonic sense of the tribal might explain why, when we see a trilling cloud of 10,000 starlings—each bird watching its seven closest neighbors for the slightest change of speed or angle, dodging hawks en masse with shrieks and chips, beak beats and hard whistles—we find ourselves calling that group not a flock or a swarm or a drove, but a collective noun that’s drenched in sound: a murmuration.

So what kind of murmur began that spring day in Vienna when a twenty-eight-year-old Mozart, jaunty in his garnet coat and gold-rimmed cap, strolled into a shop to whistle at a starling in a cage? That bird must have zeroed in on Mozart’s mouth, drinking-in the whistled seventeen-note opening phrase from his recent piano concerto:

Mozart’s melody riffs in G on a simple line heard in many a volkslied, so the starling might have been hearing similar tunes from other shoppers that whole month. Or perhaps Mozart himself had been in a few times and had whistled his line enough for the bird to imprint it. No matter how the starling learned the song, on May 27, 1784, it spat that tune right back at the tunesmith—but not without taking some liberties first.

The little songbird un-slurred the quarter notes and added a dramatic fermata at the end of the first full measure; we can only guess how long it held that first warbly G. In the next bar, it lengthened Mozart’s staccato attack and replaced his effete grace notes with two pairs of bold crotchets. And the starling had the audacity to sharp the two Gs of the second measure, when any Viennese composer worth his wig would keep them natural and in line with the key. Those bird-born G-sharps take the steady folk tune into a more harmonically complex place, ignoring the fermata-ed natural G that comes just two notes earlier and pushing toward the next note in the phrase—an A—creating a lifted E-major chord. Mozart apparently loved this edit, because he bought that bird on sight.

For good measure, he drew a little treble staff in his expense book and scored the starling’s tweaks under the note of purchase:

And under the last measure, an acclamation—“Das war schön!” (“That was wonderful!”)—scribbled in the maestro’s quick hand.

There is no other live-animal purchase in Mozart’s expense book, and no more handwritten melodies; no additional transactions were praised as schön! This is one of the very few things we even know about his purchasing habits. He’d only begun tracking his spending that year, and by late summer, Mozart had abandoned the practice and only used that notebook to steal random phrases of English. So this note of sale is special among the extant scraps from his life.

The purchase of this bird, Mozart’s “Vogel Staar,” marks a critical point for the classical period. At the end the of eighteenth century, tunes were never more sparkling or more kept, their composers obsessive over the rhetoric of sonata form: first establishing a theme, then creating tension through a new theme and key, then stretching it into a dizzying search for resolution, and finally finding the resolve in a rollicking coda. The formal understanding of this four-part structure permeated classical symphony, sonata, and concerto. By 1784, sonata form had imprinted itself on the listening culture enough to feel like instinct; Vienna audiences could rest comfortably in the run of classical forms as familiar—and thus enjoyable—narratives. And nobody played this cagey game more giddily than Mozart.

Of all the things Johannes Chrysostomus Wolfgang Amadeus Mozart brought to human sound, the most important might be his sense of surprise. His compositions, while almost always law-abiding, are full of trickery—leading tones that drop away from roots, accidentals that jar the listening mind from its diverted stupor, minuets too syncopated to dance to. His beloved Piano Concerto in D minor begins not with a sturdy melody, but an anti-tune of the same repeated notes bouncing about the orchestra. Songs from his early operas confounded audiences with their false endings. He reveled in keys like G minor, with its air of turmoil and instability.

These caprices, though stuck inside the pinfold of common practice, are what made him a star. As the old German saying goes, the music of Bach gave us God’s word, Beethoven gave us God’s fire, but Mozart gave God’s laughter to the world. He found the accidents in song that reminded music to glorify the playful, the mischievous, the pop! that sends Jack exploding from the box after so much measured cranking.

So the starling’s playful G-sharps must have felt more than “wonderful” to the maestro. Think of it—he’d whistled a tune steeped in Vienna’s golden algebra to a thing with feathers, and then the animal bobbed its little head and whistled back to him a glorious, deviant, Mozartean wink. This was game recognizing game! What a priceless moment: one of the greatest thinkers in history bonding with a bird brain.

We still know very little about the starling brain, really. Our science is only just catching up to the species’ complex body and behavior, some 225 years after Mozart’s death. Among our recent discoveries is a sturdy musical form inside one type of starling song. Though the structure allows enough variation for one starling to sound nothing like the next bird over, all courting males organize their love songs in a four-part sequence of Whistle, Warble, Click, and Screech.

Each bird begins with a set of repeated whistles—a kind of reedy introduction. Next, as the feathers at his throat seethe and puff, he weaves a run of maddening musical snippets—as few as ten or as many as thirty-five—curated into descending tones. Some of these snippets are filched from nearby species (or lawn equipment, or cellular phones). It’s here, in this second movement, that the “Twin-kle Twin-kle” meets the chackerchackerchacker, the smoke alarm, and the Bee Gees. Without stopping, he then slams into the third section, that of the percussive click solo. Syncopated and note-less rattles shoot from his beak at presto speed, as many as fifteen clicks per second. And then he ends with a fortissimo finale of loud, exclamatory shrieks, enough to wake the neighbors.

It can take him a full minute to sing through all four movements, and then the starling is silent for a moment. Some birds even bow when they’ve finished.

Nearly every courting male in the wild follows this pattern; the four movements are audible even to human ears if we listen closely enough. Because a bird can log so many random sounds in his song bank, the permutations of starling form are endless. And unlike Mozart and company, there is no discernable meter, math, or key dictating the starling’s changes from the Whistle movement to the Warble movement or from Click to Screech. The bird can do what it wants in each section for as long as it likes. This gives the courted female two distinct pleasures: She can lean on the familiarity of the song structure, but she can also hear the freestyle within the movement—a report of her lover’s unique mind.

Because of its tendency to absorb sound, the starling’s song is not tuneful as much as it is expansive. The world seeps into its music; the real meets the obsessive, the merry smashes into the flatulent. The compositions of this species are joyful and ugly and dissonant and divine. And though less predictable than the whip-poor-will’s or the skylark’s, the starling’s song is by no means less confident.

Though we know this much about starling composition, the mental process that cultivates these choices—whatever gray matter lets a starling write its own song and wills it to vary its tunes so greatly—remains mysterious. After a millennium of searching, we cannot figure out where in the brain this starling song is bred. It’s possible the whole process is the result of a mental function humans simply don’t possess. Or most of us don’t, anyway.

Mozart’s brain is as much a mystery as a starling’s. It was never autopsied, and his genetic line ended with his two surviving children. In 1801, a gravedigger claimed he’d unearthed Mozart’s skull, but no one has been able to prove it. We’ve simply spent the past 200 years guessing what went on in Mozart’s head, and as long as we keep his 600-plus compositions in heavy rotation, we’ll always have half a mind to try to figure him out. His music’s heavy presence in our lives, from “Twinkle Twinkle” to the Requiem, keeps us guessing.

The old ideas of Mozart as a perpetual child or as a mere recipient of dictation from God have dissolved in recent years, thanks to computer studies of his “autograph

scores” that show revision after revision scribbled onto the pages in multiple inks. We now know Mozart drafted and woodshedded for his entire career. He didn’t simply spit music out; musical ideas incubated inside him for decades.

Despite our better understanding of the scope of his efforts, it’s difficult to ignore the flighty irreverence he possessed, both on and off the staff. Many have wondered why a brain that prone to perfection was so hell-bent on vandalism. Mozart loved to chatter, play, and shock. Who, for example, could imagine Bach or Beethoven jumping out of his chair at a performance, as Mozart did, and somersaulting around while the soloist onstage committed a boring improvisation on a theme from The Marriage of Figaro? And not only interrupting that lame performance, but meowing a countermelody over it?

We also see a vulgar streak in several prank tunes, many composed in tandem with his masterpieces. There is, in fact, a meow duet in the Mozart oeuvre. Also, the same year he made the luminous Fantasy no. 1 with Fugue, Mozart wrote a canon of six sober voices repeating “Leck mich im Arsch” (or, literally, “Lick Me In the Butt”). Another canon from that period begins with the phrase “good night” in several languages, then a sung “phooey phooey!” and a filthy line about crapping the bed.

Away from the keyboard, Mozart was just as devious with wordplay, as seen in the polyglot prattle of his letters, like this one to his cousin: “muck!—muck!—oh muck! o sweet word!—muck!—chuck! That’s good too!—muck, chuck!—muck!—suck—oh charmante!—muck, suck!—love this stuff!— muck, chuck and suck! —chuck muck and suck muck!”

Some think the maestro’s mysterious brain was troubled by Tourette’s or, at the least, an attention disorder. His own brother-in-law wondered if Mozart “concealed his inner tension behind superficial frivolity” by mixing “the divine ideas of his music and…sudden outbursts of vulgar platitudes.” But this assumes, perhaps too hastily, that the vulgar didn’t participate in his divine ideas.

Even though we now know Mozart’s brain was not God’s fax machine, many still imagine it as some sort of sepulcher for only pristine sounds. But why didn’t he need it all—the vulgar and the formal, the right notes and the wrong notes and those whistled a half-step sharp?

A man obsessed with perfect tone might need to stay on nodding terms with aberration. What if Mozart played with bad notes and uncouth lyrics, with foreign language and nonsense, to horde all the expression he could, just as Sturnus vulgaris hordes all possible sound in order to sing?

Much earlier in his life, when he was still a baby genius playing blindfolded for the aristocracy, Mozart’s best trick was an improvisational game not unlike an eighteenth-century rap battle. A court composer or some member of the cognoscenti would play a sparse bass line on the keys, over which Mozart would improvise a melody—sometimes complete with harmony or counterpoint. Then his much older opponent would answer back with a different melody, which Mozart would rework, and back and forth again and again until the challenger eventually crapped out. Pipsqueak Mozart never did, and his royal audiences delighted in these on-the-spot reworkings of their musical rules. That’s how Mozart grew up: chasing melodies as they flew by him, hunting for the ways each note might pivot into something new. Since this inventiveness kept the Mozart family employed, one might see Wolfgang’s open receptors as a musical survival skill.

Thanks to an upper-level connectivity we’ve only recently identified, starlings are hard-wired for reception, too. Video modeling has led some scientists to suggest that starling bodies fly at a “critical” state, meaning all their physical receivers—down to the cell, maybe even down to the protein—are attuned to simultaneous and dramatic variations within the group. This connection, seen in a mass of flying starlings—dipping, reeling, curling into itself midair—is beyond biology; it’s more like physics. A starling in flight is “critical” like an avalanche, like the ignition of atoms in a magnet, because each body holds the report of its neighboring bodies—and all of those bodies’ potential—inside itself. But then again, this is merely a theory. What they do runs far past what we can understand and our evidence is somewhat spotty. Though we’ve lived with starlings for millennia, we’re still fumbling for a language to discuss certain aspects of their lives.

Mozart could have kept his starling’s cage in the room with his billiard table, where he often composed. Or it might have stood in his bedchamber, where he stayed awake with his quill and notebook (both man and songbird were prone to singing while the rest of the house slept). No matter the room, the bird lived with him for thirty-six of the most vibrant months of Mozart’s career. The maestro’s fortepiano was constantly being shipped from his music room out to the Mehlgrube for yet another concert. Leopold Mozart complained in a letter that his son’s home buzzed at all hours with rabble-rousing factions: students, rehearsal groups, goofy late-night jam sessions. Their noise was nonstop and deafening. Mozart reportedly hated being alone, even when he worked. And for these three years, work he did.

His costly apartment on the Domgasse saw sixty-plus compositions finished in less than three years. The piano concerto as we still understand it was built in those rooms. The Haydn quartets premiered there. The “Jupiter” Symphony began and Figaro ended. And with these heavy hitters came some of the most whistle-able ditties in the repertoire: the wafting waltz-time start to the Piano Concerto no. 21 and the stately intervals of the Romanze from the Serenade no. 13 for strings. Melodies that two centuries of humans have since whistled could have first been volleyed between a genius and his pet bird.

And you can bet that, if it were in earshot, Mozart’s starling junked these immortal melodies. As Mozart hammered them shiny, the bird sent the tunes back upside-down, at half-speed and double-time, and piped one inconsequential middle note for five straight seconds. It’s not difficult to imagine Mozart valuing this kind of collaboration, as he spent so much of this period reaching out to various “songbirds.” The starling was another musician to pump ideas into Mozart’s brain, like Haydn did, or Vienna’s top fiddlers, or his high-soprano sister-in-law with her gobsmacking range. Among the divas, the maestros, and the virtuosi, that caged bird stood the furthest outside the classical box, waiting to eat all the sound it was offered and spit back strange bits with starling gusto.

Picture an early morning composing session, the starling’s cage near the sixtieth key. Mozart flies into the room, fresh from dressing, with his hairstylist trailing behind him. The friseur still holds the end of the maestro’s wig braid like the owner of a spastic dog.

The bird stirs as Mozart kicks back the bench and stands over the ebonies. He needs to tease out this theme that’s been flitting around in his head for several days. He finds the tonic, a sprightly G, and then dances between it and the fourth below. Then he reverses the melody’s course and skips it upward, bouncing to the dominant fifth in an arpeggio that smacks the next octave with a Mannheim rocket exclamation point:

Mozart can barely keep up with his pen; he’s writing with one hand and playing the melody on the keys with the other. As the notes of the exposition zoom onto his staff paper—flapping merrily along as the form intended—a jalopy-fart of notes comes from the cage, countering the clean tones of the keyboard: BUM! Bweet! Chackerchacker—Bom-bah-bom-ba-ba—BAAH? bom-ba-ba Brrrup!

Mozart turns to the bird; it moves closer to the front of the cage and stares back. Starlings are more responsive to human eye contact than most mammalian pets; they know when they’re being watched and aren’t afraid to hold a gaze. It’s one of the primary traits—along with a high touch response—that allows deep bonding between starlings and humans, as we love eye contact, too. One ornithologist called the starling “the poor man’s dog” for its ability to connect and demonstrate loyalty. And sound assists this connection; what better way to bond than in the two-way conversation of a song?

Mozart opens the cage and the bird flits to his arm, screeching that same derailment (Chackerchacker bom-ba-ba—BAAH!) as it hops up his sleeve. The man keeps writing and the bird keeps yukking and sucking and mucking it up.

And now, two centuries later, not a day goes by without someone on the planet playing the result: the opening movement of the Serenade no. 13 for Strings in G major, often called “Eine Kleine Nachtmusik.” Notice how, after the exposition, the serenade dips treacherously into D minor before moving forward in a new major key. It sounds as if, for a quick measure, a little devil has whispered something shocking into the melody’s ear.

Notice, too, the wicked work of Mozart’s “A Musical Joke,” which was written in tandem with the perfect “Eine Kleine,” most likely on that same keyboard. Though smarter and not as vulgar as “Leck Mich Im Arsch,” the divertimento is doubly excruciating, a relentless twenty-three-minute parody of classical music’s traps. Notes run up and down the scale like Keystone Cops. Developments flop like punch lines you see coming from miles away. And in each of the four painful movements is a hilarious breakdown—a rusty, unrefined disturbance that explodes the joke’s mundane torture. These breakdowns play out like lines of starling talk: They are the G-sharps the bird whistled back in the shop, elevated to virtuosic silliness.

In the Minuet, the horns repeat a theme at misplaced half-steps, like howling dogs. In the Adagio, the violas trill their scales at double-time—whistling tea kettles gone rogue. The best starling breakdown comes in the last movement, when the same skipping chirps come again and again, moving like a dare toward forever, until the listener shouts “Make it end!” When Mozart finds the finale (thank God), he ends not by perching at the tonic. Instead, he crashes the ensemble together, screeching the movement to a halt. “A Musical Joke” might feature the least classical ending in the entire classical period. For the final measures, the instruments play three block chords in three different keys. It sounds as if the string players have thrown their fiddles out the window:

There, in that mangled vertical line of wrong notes, you can almost hear the starling on Mozart’s shoulder, bobbing his head, maybe even taking a crap, and chattering: Das war—Bizeet!—LECH MICH—chackerchacker bom-ba-ba—BAAH!—schön!!!

In 1787, Mozart’s luxe apartment finally became too expensive, and the family moved to a place on the Hauptstrasse with rent one tenth the cost. Even though they were paring down, Mozart took the bird with them. We know this because he made such a fuss over the starling when it died a few months later.

On that day in early June, the new Mozart home welcomed a dozen mourners in elaborate, costumey garb—giant plumes and feather fans, or maybe black masks with beaks. The guests were first treated to a dirge (arranged by Mozart) for chamber ensemble, and then the maestro recited a short elegy he’d written to the bird, his Vogel Staar.

In the poem, Mozart imagines the “little fool,” unaware that it is dead, looking down at Mozart and whistling fondly. Now up in heaven, the songbird sings for free, as has always been its custom. By the last stanza, the bird has already sung long enough to forget its keeper and collaborator. And now the maestro is left on Earth to rhyme alone (albeit masterfully, Mozart brags).

Who knows why Mozart planned this cuckoo funeral. We have no evidence that he ever mourned this way again. The verse and the dirge and the funeral party could have been a mock solemnity—Mozart rarely passed up the chance for a weird party or a good gag. On the other hand, he could have been somewhat serious, as he was a known animal lover. But why publicly mourn a pet starling and not his own father, who died without ceremony in Salzburg just a week before?

The starling funeral, like its purchase three years prior, is one of the many snippets of Mozart’s life that still confounds us. Nearly all Mozart biographers mention it among their mob of questions, which they whistle out into the void, knowing they’ll never hear an answer: Why buy a bird? Why bury it and not your father? Why a red coat? Why the puns? Why so many notes? Why a serenade one day and a butt gag the next? Is it even possible to bond with a creature only by the sound that it makes? We don’t know, we don’t know, we don’t know.

For so much is left unanswered when a man falls from heaven and writes Don Giovanni. Or when the wingbeats of countless tiny creatures lift upward and sound like thunder as they move to block out the sun. When 500 starlings drop from the sky into shallow ponds without making a sound. When a genius buys a songbird because, despite his noisy life, something is missing.

And even more remains mysterious when the genius takes to bed in his thirty-fifth year. After two weeks, his hands and feet are swollen—again and again, he blacks out. Though the women around him sob, he can’t stop telling little jokes; he can’t stop singing. Doctors let him for blood, they prod at his flesh, they guess as to what is inside him. Then he sends his pet canary from his room and the women around him weep louder. For when he banishes his bird, they know one thing for sure: He’s letting go.

Out the window and down the Hauptstrasse, the genius’s most famous opera is in performance. At one point he tells his wife he can even hear the soprano hit her top aria note. At the opera’s finale, a lonely bird catcher takes the stage. He’s covered in feathers and ready to die. He sings a string of short pips—“Pa! Pa! Pa!”—and turns just in time to see his companion running from the wings, arms outstretched. As she runs, she locks eyes with him and nods her little head, singing—“Pa! Pa! Pa!”—right back.