We humans can hear pretty well. We’re also quite good at making complex sounds. So we sing. Almost alone among our fellow mammals, we sing long and complicated songs.

On land we have no serious rivals as singers. Lions communicate with roars that carry across the African night with a sound like a giant’s belch; hyenas locate each other with a spooky whoop; wolves howl to keep in contact at distance; families of gibbons sing in chorus at dawn as a daily way of reclaiming their own area of rainforest; the carnivorous grasshopper mouse will send out a sustained trill. The tree hyrax—a rodent-like creature that’s actually related to elephants—makes an astonishing sound in the forests at night, based around a crazy and repeated screaming. And though all these sounds are wild and inspiring and wonderful, they’re not the sort of thing we readily call music.

Whalesong is one of the great discoveries of recent decades. It was first discovered by American servicemen listening out for Soviet submarines in 1952. Since then whalesong has been much studied, especially the songs of humpback whales. Astonishing things have been revealed: a new song, said the cetologist Phillip Clapham, was found to ‘spread like a wave across the Pacific Ocean’ as different individuals picked it up, learned it and performed it: a clear example of musical culture passed on from one whale to another.

But we’ve known about this for less than a century. The songs of birds were part of our lives before our ancestors were fully human.

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We learned melody from the birds: and thus music became a part of all human cultures. To create music, as we humans understand the term, we set melody against rhythm. And all of us mammals are natural rhythmicians. We humans spend the first nine months of our existence listening to the great drum solo of our mother’s heartbeat. We are powered by that immense even-time rhythm; four-four is the most basic time signature that musicians work in, and it’s the one that cuts deepest.

But it’s my belief that we filched melody from the birds. Listen to a blackbird (you can do so easily enough by googling ‘blackbird RSPB’). It sounds astonishingly like a human whistle: relaxed and easy, as if the whistler was leaning against a wall with his hands in his pockets on a warm day. And we humans can imitate this. To do so is a natural impulse.

And it’s a tune. It’s melody. And it’s more or less music as we know it. Across the world you can hear birds every bit as tuneful. The first humans who walked upright on the savannahs of Africa would have listened to the songs of robins and larks, found comfort in them and imitated them. And added rhythm.

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The first musical instruments created by humans were bird flutes. These were made of bone, and they were capable of making two or three notes that sounded like the notes of birds. The oldest of all is the Divje Babe flute found in Slovenia. It’s 67,000 years old and very fragile, made from the femur of a young cave bear, an animal that became extinct 25,000 years ago.

Other flutes have been found from more recent times, and they are often made from birds’ bones. Bird bones are hollow, as we have seen: they are practically a flute already. A five-hole flute was found in Ulm in Germany, and it’s about 35,000 years old. The earliest instruments that are not flutes are very recent indeed. They date from 2600 BC: a collection of harps and lyres found in Sumeria.

Surely it would have been easier to make a plucked instrument from a length of gut. Or a melodic percussion instrument, like a xylophone, from chunks of wood. But that didn’t fit our first ideas of music. We wanted to sound like birds.

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Birds and mammals have different equipment for making sounds. Birds have a syrinx instead of a larynx: a forked organ that some birds use to sing two notes at the same time. The syrinx is named for a chaste nymph who was lustfully pursued by Pan. She hid in the water and prayed that she might be transformed into a reed and so escape Pan’s attentions. Her prayer was granted and Pan turned the reed into… pan pipes.

As we have seen, birds also breathe differently from us mammals, with adaptations that help them to fly, for powered flight is highly expensive in energy and requires a constant access to unbreathed, oxygen-rich air. As a bonus, this also enables birds to produce long, loud and almost continuous sounds, and to put on a performance that’s way beyond human singers, forever limited by our in-out method of breathing. Virtuoso performers on wind instruments can master circular breathing, a way of seeming to exhale continuously. The trick is done by forcing stored air out by pressure of the cheek muscles while inhaling through the nose. Birds can do the same thing without training: it’s in the structure of their breathing apparatus.

A SKYLARK. The miracle is not that skylarks can sing forever on a single breath, it’s the fact that they are equipped in a manner that makes continuous singing possible.

So when you listen to a skylark singing at the top of its voice while flying steadily up towards the clouds, it’s not quite the same as asking you to run a mile while singing the ‘Hallelujah’ chorus. The miracle is not that skylarks can sing forever on a single breath, it’s the fact that they are equipped in a manner that makes continuous singing possible.

Every song says something about the singer. A good burst of song tells listeners that this is a bird in very good shape. It has to be: the wren whose song fills your garden is tiny; you could hold a dozen in your cupped hands. Their astonishing Brian Blessed level of vocal power is a demonstration of the strength of the species—and of the individual.

A bird puts everything into a song. It’s a massive explosion of energy, even when it sounds as laid-back as a blackbird. So if you listen to a bird with a critical ear, you can make accurate judgement of just how fit and strong that individual happens to be. And that’s what female songbirds do. They judge a male’s song just as a peahen will judge a peacock’s tail.

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Birds hear better than us. Their vision, as we have seen, is more receptive to colour than our own. Their hearing is better at distinguishing very brief passages of sound. Let’s go back to the wren in your garden. If you listen to him, you will find that he finishes his song with a powerful sustained trill. It’s pretty impressive for such a tiny bird, but to a human ear it’s not very interesting musically.

So record it and then play it back slowed down. You will find something completely different. (There are examples on the internet.) I have listened to a recording of a wren’s song that lasted 8.25 seconds, and listened to the same thing slowed down to last 66 seconds. And the transformation is startling: from the chrysalis of a dry and rather mechanical trill you find emerging, like a butterfly, a gloriously sweet melodic line. Analysis revealed that the wren sang 103 separate notes in the course of that eight-second song. He was singing at a rate of 740 notes a minute. Guitarists reckon that you move into another dimension of shredding when you reach a speed of 170 notes a minutes. It takes a virtuoso on the instrument to rival a wren.

Does a bird hear each individual note? The easy answer is to say that they must do, or what would be the point of singing them? But we can do better than that. The whip-poor-will is an American bird famous for its three-note call; its name is an onomatopoeia. But if you slow the call down, you will find that there are actually five notes in there.

The mockingbird is a famous mimic, and it likes to imitate many different kinds of birds, among them the whip-poor-will. Slow down a mockingbird’s imitation of a whip-poor-will and you find… five notes. In other words, even if birdsong does move humans very powerfully, it’s still a bit beyond our scope to hear every note.

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Birds mostly make noises so that other birds can hear them. The sounds they make have a meaning and are uttered with a purpose. It’s communication. You can call it language if you like, though most philosophers’ definitions of language are skewed in a desperate attempt to demonstrate that language is uniquely human: we want to keep the club exclusive. Plenty of evidence has been discovered to make the barrier between human and non-human communication fuzzy. Famous examples include Washoe, the chimpanzee who learned American Sign Language, and the honeybees who inform each other about food sources by means of the famous waggle dance.

Birds are able to communicate with each other through sound, so let’s leave it at that. You can break this down into two different kinds of sound, with radically different functions: call and song. Call tends to be the very direct communication of a simple idea, and so the sound is usually brief and straightforward: often monosyllabic, and seldom what you’d call tuneful. The most common calls are those that give a warning of danger—an alarm call—and those that give ‘I am here’ information, a contact call.

Song is much more elaborate and complex. Song is a way of passing on information not about the world but about the individual singer: how effective he is and how experienced (singing birds are usually males). Not all birds sing. In fact, most don’t. All the same, birdsong is a global phenomenon and those birds that do sing have been phenomenally inventive and successful. They have also given delight across the centuries to humans.

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Are blackbirds altruistic? Step out into your garden, or take a less well-trodden path in the park, and at once you hear that rattling retreat of a blackbird. So you need to ask yourself: is this altruism in action? Is the bird putting himself at a disadvantage by making this call, attracting attention to himself and thereby handing the advantage to other birds? Is it a reciprocal favour from which everyone benefits, like letting people get out of the lift before you get on?

It’s an argument that can chase its tail forever. You can talk about cost-benefit trade-off. You can suggest that by uttering an alarm call the bird is warning his own relatives of danger, thus he is looking after the future of his own genes. You can argue that an alarm call is also a signal to the predator: it tells him that he has been spotted, so there’s no point in continuing hunting operations around here. It’s also possible that the blackbird’s sudden shout is a startle device, one that stops the predator in his tracks for a fragment of a second, enough to allow the blackbird to retreat.

Pheasants are great exponents of the startle technique. They will lie doggo in cover until you are almost on top of them, and then they will break cover with the most fearful din they are capable of. It’s an alarm call, and it frequently makes a human jump. By the time you have recovered, the bird has gone clear.

In woodland you will often hear a thin, high-pitched whistle. This is a universal alarm call, one that many species will use to pass on information of potential danger. It’s a very hard call to locate, so the bird isn’t really giving himself away, and it works from one species to the next, so it’s a pooling of resources. It’s a kind of Esperanto: a universal language of the hunted.

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I’m here! Sometimes with an implied follow-up: where are you? Or follow me! Or, with a chick, feed me!

The calls will be brief, mostly monosyllabic and quite often repeated. They are useful if you want to be found in, say, a woodland canopy, where you can’t see for more than a few inches. Birds will call and call back: it’s useful information and a form of reassurance.

Of course, this could also be a come-and-get-me signal to an alert predator, so when there’s a predator around it pays to shut up. And that means a sudden silence is as good as a shout. Stopping your contact calls is a silent alarm signal, an important warning for all that can hear: especially mates or young.

If you get close to a feeding flock of flamingos, you will find a comic element to their elegance and beauty. From a distance, you are overwhelmed by the mass of pink feathers—all courtesy of the carotenoids, of course—and the long, lovely lines of their bodies. But when you’re up close, your ears are filled with a daft quacking: thousands and thousands of birds, all quacking every now and then, so that it sounds like a great rolling thunder of quacks. Bring in a hyena or an African fish eagle and the quacking stops, as if a switch has been thrown: and then the birds take to the air.

Watch a skein of geese flying over: always in echelon, like cyclists in the Tour de France. They do so for the same reason: it’s much more energy-efficient to travel in someone’s slipstream than to take all the pressure of the air on yourself.

Geese constantly honk as they fly. It’s a valuable way of keeping in touch. It is important to know precisely—to the inch—where the next bird is, because that way you keep the formation tight and all except the lead bird can save energy. This is especially useful on migration flights, when geese will often travel at night, but it’s useful at any time, because you can’t see the bird behind you. I also suspect—though this is pure speculation, so miss this bit if you have a taste for scientific rigour—that the constant honking is a form of group solidarity, all us geese together, and as such it’s a powerful encouragement for the geese to spell each other and take turns at the front. Give all the work to a single goose and it’ll slow us all down and make us all less efficient. Taking turns is good for everyone. And so they honk.

JACKDAWS. When a flock of jackdaws flies over, they will jack cheerfully to one another.

Contact calls are seldom pretty or elegant or heart-stopping. There’s little music to be found here. They are basic survival tools, and if you listen out you will soon learn what species makes what call, and so you will be let into the secret. A jackdaw calls, Jack! Jack! And a flock of jackdaws will often all call together, so that I am reminded of a snooker hall. A single game of snooker is a mixture of silences and sharp clacks as ball hits ball. But when there are thirty tables at a snooker club in operation at once, the clacking is continuous, so that the entire quality of the sonic experience is changed and it becomes an unending sound that means snooker.

And when a flock of jackdaws flies over, often revelling in their ability to ride the wind, they will jack cheerfully one to another, so that the air is filled with a great rolling and jacking. It’s the sound of togetherness and of the birds’ own comfort—and, I dare say, joy—in sharing the air with their own kind. At cricket matches the Barmy Army sing their own name endlessly, or at least they do in the evening session when many of them are capable of little else. Jackdaws are doing the same thing.

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Call is about staying alive. Song is about making life worth living. Broadly speaking, anyway. If you’d prefer that a bit less anthropomorphic, call is about not dying while song is about living forever. Song is about making more birds. It’s about sex and territory, and for many birds they’re pretty close to being one and the same thing. Every song every bird ever sang is the song of life.

When a cock bird sings out he sings the song of himself. Sure, the song will tell other birds and human listeners what species he is, but that’s just the start of it. He will also tell the world what kind of individual he is: whether he is a bird that a male rival will fear, whether he is a cock-bird that a hen-bird wants to mate with.

A song is an invitation to share genes; to have a punt at the task of becoming an ancestor; to try to make sure that, though your body will die, your genes will live forever.

Song is first a signal: both a come-on and a piss-off. It’s a come-on to likely females and a piss-off to rival males. When a great tit sings a ringing, simple phrase in the early spring—often transcribed as teacher-teacher-teacher—he is saying that the great-tit niche in this place is more than adequately filled: so if you’re a male great tit, move on, and if you’re a female great tit, move in.

But the song doesn’t just give information about the species and the sex of the singer. It also gives the listener important information about the individual singer. It’s hard to sing; it’s still harder to sing well; it’s very hard indeed to sing loud and sing long. A really good song tells the males that this is not the bird to take on in a singing competition, still less to pick a fight with. It also tells the hens that this is a bird capable of defending a rich territory packed with food resources, the perfect place to bring up a brood of little great tits. In short, the singer is a damn good prospect.

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Territory is not the same as property. No doubt human ideas of ownership can be traced back to our atavistic territorial urges, but the great tit doesn’t own a stretch of garden in the same way that a person owns a house or a field.

For a start, it’s not a permanent thing. Most birds will abandon not only territory, but also any notion of trying to hold on to it for most of the year. The urge for ownership comes with the seasonal urges for procreation, and it’s abandoned as the seasons change.

Secondly, the bird can’t develop it. He has no rights over it and many other species of bird will hold territories that coincide and overlap with what he considers his own territory. Mostly, that doesn’t matter. The wren’s song is different from the great tit’s, and since he occupies a different ecological niche—different food, different ways of looking for it, different places to look for it—he won’t be considered a rival. So the two coexist: you can hear your wren singing at 740 notes a minute in the same corner of the garden as the great tit’s teacher-teachering. The wren will be in the undergrowth at the bottom of the tree, the great tit will be at the top.

The boundaries of a territory may not be tightly defined, in the legal, fence-building sense in which we humans understand it. Territories can overlap. A great tit may tolerate another great tit on the fringe of his territory, especially when he’s busy at the other end. But best not try singing your head off just by the nest hole: that’s not so much asking as begging for trouble.

Territory is a looser concept than we imagine if we think of our own homes. But all the same, it’s life and death to a territorial songbird. And it is established and held by means of song.

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Broadly speaking, there are two kinds of birdsong and two kinds of singers. There are stereotypical singers and there are repertoire singers. These categories aren’t exactly hard and fast, but it’s a useful idea, especially when you, dear reader, are trying to learn a few songs and tune into the wild world with your ears.

Stereotypical singers sing the same song again and again and again. They never get bored with it. Take a chaffinch, the finch whose lovely colouring we discussed in the last chapter. Chaffinches have a range of calls, and one of their contact calls sounds pretty much like finch. And that gave the name to the whole family of chunky-billed seed-eaters.

CHAFFINCHES. One of the chaffinch’s contact calls sounds pretty much like finch.

Chaffinches are one of the first birds to start singing in the British spring, and they’re always welcomed for that reason. It may not be the finest or the most inventive song in the wild world, but it’s the chaffinches’ own and they give it everything. It’s an accelerating succession of notes that ends with a flourish. It’s said to be a picture in sound of a fast bowler in cricket: a rapidly quickening run-up followed by the explosive delivery stride. It builds up and then it finishes with a bit of modest style.

And—er—that’s it. Once you’ve learned it you’ll hear it right through the spring. It’s not overly fancy, but it works for the chaffinch. And to a human ear every chaffinch sounds pretty much the same pretty much all of the time.

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I was once involved with some people who wanted to invent a birding app like Shazam: you could make your phone listen to a bird singing and instantly know the name of the bird. I was writing a book on birdsong at the time and it seemed that this was a Great Business Opportunity.

I was a bit of a wet blanket, I’m afraid. Birds are individuals, I said, and they sing as individuals. Even chaffinches. It’s not like a record: every one is different. They’re not clones. They don’t sound like clones. Or machines. Or records.

It never got off the ground, though there are now apps that claim to pull it off: one called Warblr, another called ChirpOMatic. Reviews say they are some way short of infallible. We try to avoid stereotyping humans on the lines of gender or race or profession; we should also avoid stereotyping birds. We should even avoid stereotyping stereotypical singers.

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Italian chaffinches sing with Italian accents. There was a time when I made a visit to Rome every other year, always in the spring. On Sunday morning I would take a stroll in the Villa Borghese gardens, and there I would hear recognizable chaffinches that sang slightly but noticeably differently from the chaffinches in my garden at home.

There are regional variations in birdsong. It’s a relatively subtle business, but it can’t be all that subtle if I can pick it up. It’s a bit like hearing your favourite band live: your favourite song doesn’t sound quite like it did on the album. You know it so well you can tell the difference: and that makes the experience all the more meaningful. In a way it humanizes the music and makes you more closely involved with the band and their songs. And in the same way, the variations in birdsong bring us closer to the avian singers. In both cases, for the listener, there is a sense of belonging that wasn’t there before.

And this demonstrates again that not even stereotypical singers are slaves to their own song. The force, the volume, the exuberance and the number of times they can sing it give important information about the power and effectiveness of the individual bird: and even in a bird that thrives on repetition there is musicality, for that comes in the natural and subtle and inevitable variations.

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Repertoire singers raise the game. They are being judged not just on volume and power and endurance: they are also being judged on their musicality. The more complex the song, the more desirable the singer is in the ears of the females. The females are more inclined towards males with greater range and variation: yes, we’re back in the realm of female choice. Birdsong delights human ears. Birds sing in order to give delight. But it’s the female birds of the same species that decide what is delightful. They go for the songs that move them. The brain of a female nightingale is chemically affected by the song of a really good male.

So you can listen to the blackbird and admire not just the fluting qualities of the whistling, but also the variety: the way the bird sets out on a voyage of musical exploration. The more successful this voyage, the more intimidating and attractive he is.

He will mix sweet notes with some more challenging ones, and he will throw in some passages that sound as if he was using an effects pedal, like a guitarist seeking a ‘dirty’ sound. He is very consciously a musician. That is to say, he doesn’t sound, to human ears, like a creature driven blindly by pure biological ends. This is obviously speculation, but it certainly sounds to me as if the blackbird is lost in his own music. It sounds as if it’s music first, biology second.

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Song thrushes are also great garden songsters, and they’re easy to pick out because they repeat. They throw in a phrase, repeat it two, three or even a few more times if they really like it, and then they move on to another. As they do so they take musical ideas from the world around them. They are not strict parroting mimics, but a sound with the right sort of pitch and tone will drive their musical ambitions and get them going.

If you are in a place with big mature trees, there are likely to be nuthatches around. One way of finding out if they’re actually there is to listen to song thrushes, for they love to try out nuthatch variations. At my place, on a floodplain in the Norfolk Broads, the song thrushes often include the piping of oystercatchers in their repertoire. I knew that a greenshank visited a marsh in Suffolk because I heard a song thrush chanting like a greenshank.

Song thrushes also take on human-generated sounds. I have heard recordings of a song thrush mimicking a shepherd’s whistle and a lawnmower, and there was one I knew that imitated the warning signal of a reversing tractor. It sounds playful, and in a sense it is: but it’s also the most serious thing a song thrush ever does in its life. That’s because the bird with the widest repertoire has a major advantage when it comes to the task of becoming an ancestor. And that’s a prize worth singing for. Singing your guts out.

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Nightingales aren’t night birds. They sing all day as well as all night. For a very brief few weeks in spring they arrive in the southern part of England and sing louder and longer and more flamboyantly than any other bird that breeds on our damp little island.

They’re best heard at night because there’s no competition. They belt out an extraordinary solo of intense whistles, powerful throbbing, resonant drumming and complex phrases of music, some of it as melodious as the sweetest blackbird, other bits as challenging as Schoenberg and Stockhausen. Even in the day they effortlessly surpass all those around them, drowning them out with a mixture of volume and extravagance, like a lead guitarist turning his volume up to eleven.

It’s a song that’s been hymned and praised and celebrated across the ages: Romeo and Juliet, John Clare, Coleridge, Shelley. People have said that the song is so wonderful they can hardly bear its continuation: it’s too much, too intense, too demanding. Certainly it’s not late-night easy listening.

THE NIGHTINGALE. For a few weeks in spring they sing louder and longer than any other bird on our damp little island.

One study showed that a male nightingale had a repertoire of 250 phrases that he had assembled from a vocabulary of 600 different sound units. All this is desperately demanding of the bird himself: he must have the strength and stamina for that endless performance, and the power for its impossible volume: a nightingale in song can be heard from a mile off on a still night. He must also have the experience and the musicality to assemble the song in a manner that pleases some of the most demanding musical critics in creation: the female nightingales.

This bird is so remarkable and so distinctive that if you’re in the right place at the right time, you will recognize a nightingale—even from a dense chorus of other avian singers—the instant the first note is uttered.

And as the bird continues almost to the point of exploding, so you will wonder why the song really needs to be quite this wonderful.

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Marsh warblers can out-sing nightingales. At least in some respects. They aren’t birds you come across often: only twenty to forty pairs breed in Britain every year. And they don’t blow your head apart like nightingales. They are subtler, but a great deal more complex. They can sing for an hour without pause and belt out a song of such wit and inventiveness that it takes a trained ear to appreciate it. It’s a bird you might pass by, but once you take the trouble to pause and listen, the bird’s extraordinary brilliance comes to you. It’s like some deceptive pieces of music: sounds simple but it really isn’t.

A marsh warbler builds up an individual repertoire by listening to others of its kind—and also by listening to other birds. Research in a small population of marsh warblers showed that they imitated 212 different species of bird, and that each singer had an average repertoire of 76. They sing the songs and calls of birds that live and breed around them in the nesting area. They also sing like the birds they hear on their wintering grounds in Africa. And the sounds they pick up as they migrate between the two. If you have a good enough ear, you can hear a chaffinch’s finch call melding into the call of a puffback from Africa, and a blackbird’s song woven into that of the white helmetshrike, another African.

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So we’ve established that birdsong is about territory. That is to say, it’s about sex, procreation, food, protecting a female from marauders, raising young, becoming an ancestor. All good biological reasons. And that’s enough to satisfy you if your mind is purely scientific. But it leaves a few things unexplained. You impoverish yourself if you accept only science, just as you impoverish yourself—perhaps more greatly—by ignoring science.

So consider this about marsh warblers. The song is specifically sung to repel rival males. But the song can also bring males together. You can sometimes find three or four of them in close proximity, all singing. They do so more quietly, more economically, than they do when singing territorially. They are singing for the sake of the song. For the music.

They will be swapping material, which will be useful to them, because the more variations you can sing, the more attractive you become. But the biological imperative seems remote from such jam sessions: it seems that the music is what matters. Or do you prefer to think that the birds are making long-term plans for the next mating season?

If you don’t like the idea of birds as conscious planners, then you have to accept them as lovers of music for its own sake. Could any great musician give a great performance entirely for an ulterior motive? Entirely because at the end of the performance he was going to be paid? Surely not. Even the most money-grabbing of musicians gets lost in the music—music for its own sake. And I suspect that’s true about the great avian singers that we find with such joy all over the planet.

And that’s one of the things that birds and humans have in common. One more reason why birds are the interface between humans and the wild world.