Sounds Wild and Broken, page 20
The ancestry of most living frog species is also rooted in Gondwana. There, two main branches formed. One, on land that would become Africa after Gondwana split apart, led to the pond frogs, Australasian tree frogs, and narrowmouth toads. The other, South America, gave rise to all American and European tree frogs, toads, and Australian ground frogs. To this day, South America and Africa are home to the majority of frog taxonomic families. Away from these centers of origin, we mostly hear the few families that managed to cross oceans and colonize new lands. How these frogs crossed the ancient oceans is not known, but the small number of families that made it across—about 10 percent of South American and African taxonomic diversity—suggests that rafting across salty water was a rare event.
The original homeland of the songbirds is the Australo-Pacific, an area now divided into Australia, New Guinea, New Zealand, and eastern Indonesian islands. An ancestral group of birds split into two in this region about fifty-five million years ago. One descendant lineage led to the modern parrots and the other to modern songbirds. Both groups are highly vocal and comprise species with well-developed vocal learning and culture. Combined, these two branches of the bird family tree comprise more than half of the nearly ten thousand living bird species. In many soundscapes, they are the dominant singers alongside the insects.
The extraordinary sounds that I heard at Crowdy Bay, then, are rooted in the evolutionary homeland of songbirds. Cockatoos and parrots, common birds all over Australia, have lived here since their ancestors split from the songbirds. Butcherbirds, Australian magpies, and willie wagtails all also belong to deep branches of the Australo-Pacific songbird family tree, kin to ancestors that left the region and evolved into modern crows. The lyrebird stem of the family tree dates back nearly thirty million years, and its complex song is evidence that ancestral songbirds were accomplished singers. Wattlebirds, friarbirds, and honeyeaters belong to another deep branch, one whose descendants live only in the Australo-Pacific and are now among the noisiest and most diverse birds in the region.
In genealogical terms, the songbirds elsewhere in the world are a subset of this diverse array of Australo-Pacific birds. The sounds we hear outside of this region are elaborations of the legacies of small groups of emigrants, dispersing birds whose descendants produced marvelously diverse soundscapes across the world. But to my ears, no continent’s songbirds have quite the range of timbre, rhythmic pattern, and vigor as those of the Australo-Pacific.
Songbird emigration from the Australo-Pacific happened repeatedly, but two waves stand out in their long-lasting effect on the distribution of birds around the world. The first wave populated Asia and then the Americas but left no living descendants in the Middle East and Europe. On Saint Catherines Island, the great-crested flycatcher and Acadian flycatchers are among this number. The second wave founded a lineage that now comprises more than half of all living songbird species. Most of the familiar voices of songbirds across Asia, Africa, Europe, and the Middle East belong to this group of emigrants: thrushes, larks, swallows, finches, weavers, Eurasian and African sparrows, starlings, and “Old World” warblers and flycatchers. A few of these bird families also came to the Americas. But American soundscapes owe much of their character to the flourishing of just one offshoot of this second wave. The American blackbirds, warblers, tanagers, sparrows, and cardinal-grosbeaks are all descendants of this clan.
This view of Australia as the crucible and exporter to the world of songbird diversity, grounded in the latest analyses of bird DNA, upends some traditional views about evolution. Biologists long assumed that Australian animals and plants originally came from Asia, side branches of a story that they believed was firmly rooted in the Eurasian landmass. As Australian biologist and writer Tim Low pithily states in his groundbreaking exploration of Australia’s birds, Where Song Began, nineteenth- and twentieth-century biologists, including luminaries such as Charles Darwin and Ernst Mayr, believed in “a version of terra nullius, an empty land filling with good things from the north.” This colonial view of biogeography is still lodged in taxonomic language: “Old World,” “New World,” “Oriental,” and “Antipodean,” as if geologic time and the tree of life were rooted in northern Europe.
Songbirds are not the only voices in the avian soundscape. The combative chirping and frenzied wing whirs of hummingbirds are unique to the Americas. But thirty million years ago, hummingbirds were European, as attested by fossils from Germany. This ancestral stock then colonized South America. The European hummingbirds went extinct, but in South America the birds found a congenial home and, in partnership with flowering plants, rapidly diversified.
A taste for sugar may have stimulated the evolutionary flourishing of both hummingbirds and songbirds. Genetic changes to taste receptors happened early in the evolution of both groups, repurposing an umami receptor to taste sugar. This new taste for sweetness allowed the birds to seek out and benefit from flower nectar and the sugary exudations of sap-feeding insects. Just as the origin of flowering plants forever changed the sounds of Earth by giving a boost to the diversity of many singing insects and other animals, the diversity of birdsong is partly founded on a link between birds and Australo-Pacific plant sugars. Songbirds, hummingbirds, and parrots are all highly vocal, and many of them learn their songs and have vocal cultures. In the rich voices of birds, we hear the sweet gifts of flowers and sap.
In every one of the ancient dispersal events from the Australo-Pacific, the arrival of a small band of ancestral birds seeded a later flourishing. As we listen, we hear the legacy of chance events from millions of years ago. Had a different group of birds been blown to Asia from the north coast of New Guinea or wandered across the Bering land bridge to the Americas, bird soundscapes would have a very different geographic structure. Overlain on these quirks and accidents of history are millions of years of speciation and adaptation in each of the descendant populations. Each species experienced its own story of sexual elaboration and environmental adaptation. Combined, these are the stories of evolution’s creative manufactory of sonic diversity.
The stories of dispersal and kinship come from analyses of the DNA of modern species, supplemented by information from fossils. These studies also reveal something about human senses and affinities. We have approximately one hundred times more genetic information available from birds than from insects, and so reconstructions of the avian past have wider and sturdier foundations than those of insects. Insects do not lack DNA. What is missing is research funding and scientific attention.
Birds are popular subjects of scientific study partly because they catch our eye. Bird colors entrance us, and their bodies are large enough for the sight of them to evoke the human imagination. Icarus flew on wings of feathers, not of insect exoskeleton. The Christian Holy Spirit descends as a dove, not a cicada. Birdsong more closely approximates the frequencies, timbres, and tempi of human speech and music, further linking them into our senses and thus our aesthetic affinities. Were insects as mellifluous and colorful as birds, we’d devote more attention to their study.
Just as the breeding displays of animals often plug into the preexisting sensory bias of their mates, our fondness for birds reveals our sensory biases, born in the ecology of our primate lineage—a fondness for red to see ripe fruit and healthy flushed skin, a love of elegant motion to judge another’s vitality, and ears eager to hear the information carried in human sound. Birds’ prominent roles as poetic, religious, and national symbols are a product of these particular tunings of human eyes and ears. If we communicated by ultrasound, as rats do, or by scent, as many salamanders do, we’d have rodents and newts on our coinage and in our sacred texts. Our sensory proclivities also spell doom for many bird species. One in five vertebrate animal species are captured and traded worldwide. Species with feathers and songs that please the human eye are especially popular. A few insect species are captured and kept, especially crickets in parts of Asia, but wildlife trade is an insignificant threat to most, unlike bird species whose evolutionary path led them to the unhappy end of being attractive to humans. Yet alongside peril is the power to provoke change. Human aesthetic responses prompt moral concern. A Robin Red breast in a Cage / Puts all Heaven in a Rage. Our senses lead to desires for both consumptive possession and protective care. Perhaps by appreciating the origins and fragility of the marvels that delight us we might tip our desires and actions toward the conservation of wild beauty?
The sounds of Mount Scopus, Saint Catherines, and Crowdy Bay seem so ephemeral and light, dissipating as soon as they are made. Despite being fleeting, they are also layered records of history. Every voice carries the imprint of its clan’s origin and dispersal. A soundscape is therefore an accretion built over hundreds of millions of years. As I listen, I am often caught up in the moment-by-moment melodies and tonal layers of soundscapes: cadences of whistling birds and textures of insect sound, the varied pulses and timbres of species playing against one other, or the antiphonal calling of rivals or mated pairs. Alongside these delights of the instant is an invitation to hear the stories of evolution’s past. These legacies of animal movement and plate tectonics are often older than the ground under my feet. Saint Catherines Island is made of Pleistocene sand and more recent dune deposits, none older than fifty thousand years. The sandy soils of Crowdy Bay are as young as those on Saint Catherines Island, underlaid by two-hundred-million-year-old lava. The limestone of Mount Scopus is an uplifted seafloor, the remains of salty ooze sixty-five million years old. The sounds atop these soils and stones are often tens or hundreds of millions of years older.
Sound, made of breath and gone in an instant, can be older than stone.
Listening to the animal voices around us, we hear the legacy of a sonic geology made of vibrations in air, diversified by plate tectonics and the ancient movements of animals across continents. Unlike stone, no durable physical substance carries sound’s many shapes through time. Instead, the form of animal sound has traveled in fragile strands of DNA, remade every generation and, in species that learn their songs, through an unbroken chain of connections between youngsters and their elders.
PART IV
Human Music and Belonging
Bone, Ivory, Breath
Forty thousand years ago, in ice age caves in what is now southern Germany, a new kind of sound was born. This sound was simple, just a string of whistled notes, seemingly unremarkable compared with the complexity and range of birds and insects that sang outside the caves. Yet the sound was revolutionary. In the moment of its creation, Earth’s generative powers leaped forward, powered by cultural evolution.
Listen: primate lips blow into shaped bird bones and mammoth tusks. A chimera emerges. Hunter’s breath animates the skeletons of prey. The air vibrates with melodies and timbres from a source previously unknown anywhere on Earth: musical instruments.
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Time has honeyed the whiteness of bone and ivory. Millennia spent buried in dust and rubble have imbued a stain the color of pinewood. In a dark room, resting on black cloth in glass cases, the objects glow under gentle spotlights. I’m in the Blaubeuren Museum of Prehistory in southern Germany, gazing at flutes crafted nearly forty thousand years ago from bird wing bones and mammoth tusks.
The flutes’ seeming fragility astonishes me. In preparation for this visit I’ve pored over technical papers and studied photographs. On paper, the objects look substantial, like sturdy bones familiar from a dinner plate or zoology lab. In their presence, though, I’m confounded by how old and delicate they appear. Their timeworn hues, papery-thin walls, and tiny fracture lines teach my senses the meaning of great antiquity. My body and emotions finally understand what my mind has tried to grasp.
I’m in the presence of our species’ deep cultural roots. These objects are the first known physical evidence of human instrumental music. They are three times older than human agriculture. Two hundred and forty times older than the age of oil wells and gasoline. No other species makes musical instruments, although a few come close. Some tree crickets cut holes in leaves to amplify the trill of their wings, and mole crickets shape their burrows to act like trumpets. In both cases, the insects are amplifying existing voices, not creating new ones. Orangutans sometimes press leaves to their mouths to make kissing sounds, but they do not, as far as we know, reshape the leaf for this purpose.
A griffon vulture wing bone: at one end, V-notches cut into the bone, like modern end-blown bamboo or wood flutes. Along the convex side of the bone’s gentle curve are four holes. Part of a fifth hole is visible in the broken, unnotched end. The holes are spaced so that the fingers of two human hands would easily rest against their openings. Each hole is beveled, and the precise knife marks left by a stone tool are still visible in each depression. The beveling creates a dimple exactly the size of a human fingertip. Every cut speaks of intent. This is a bone sculpted to fit the human hand and mouth.
The maker used the bird’s radius bone, the slimmer of the two forearm bones of the vulture, and so the flute is thin as a twig, only eight millimeters across. But it is nearly as long as the top of my forearm. Griffon vultures spend their days soaring in search of carrion and have huge wingspans, wider than eagles’, making their wing bones an excellent source of long tubes for Paleolithic flute makers.
Fine fracture lines divide the bone’s smooth surface into a dozen pieces. These fragments were recovered from cave deposits, then reassembled and interpreted by University of Tübingen archaeologists Nicholas Conard, Maria Malina, Susanne Münzel, and their colleagues. A gash on the right side of the flute, just above a finger hole, speaks of the ephemerality of this thin-walled bone and how improbable was the flute’s journey from the Paleolithic to our modern world.
This is one of four bird-bone flutes from the caves of this region, all recovered from deposits dating to the early Aurignacian, a time period immediately after the first arrival of anatomically modern humans in what we now call Western Europe. Two of the other flutes are known only from small finger-hole-bearing pieces. The third is made from a swan radius, incomplete but with three clear finger holes, reconstructed from twenty-three fragments.
Here in the Blaubeuren Museum, adjacent to the griffon vulture flute, sits a flute of a stouter design. It has three beveled finger holes on the concave side of its curvature. One end seems deliberately notched into a deep U. A splinter extends down from the third hole, suggesting that the flute was originally longer. Unlike on the bird bone, two seams run down the length of this flute. Each seam is crossed by repeated short lines, like suture marks on a long incision.
This flute is made from mammoth ivory, a material unfamiliar to my modern eyes. The griffon vulture radius is easily recognizable as a bird bone, a giant version of chicken and turkey bones. Mammoth ivory, though, has no everyday contemporary analog. Its surface has the patina of well-worn leather, an illusion emphasized by thin walls of the flute that look like tanned animal hide. The finger holes and ends, though, appear cut into solid bone. The object seems exotic to me, but for Paleolithic people the mammoth was a staple of both diet and craft. Their caves are littered with mammoth ivory and bone: tools, ornaments, cooked bones, and partly worked tusk pieces. Mammoth ivory was multifunctional, and judging from the remains left in caves, often discarded or abandoned. The plastic of the Paleolithic, perhaps, but locally sourced from free-range animals.
Bird bones are hollow and fit readily in a human hand, good matches for flute making. But a mammoth tusk is solid and hard to carve. Whoever made the mammoth-ivory flute spent days at the task.
Close study of cut marks on the flute and experiments by modern archaeologists and reconstruction experts suggest the manufacturing sequence used by the ice age craftspeople. First, they used sharp stone cutters to excise a portion of a large tusk, making a stave or blank. Thousands of tool remnants in the caves show that they also used this technique to carve blanks for hunting projectiles from reindeer antlers. Ivory is not easily turned into a tube, and the artisans lacked drills. So they pared the stave into a cylinder, split it lengthwise, then scooped out each half before reassembling the whole, now as a tube. To do this, they exploited the growth form of the ivory. Mammoth tusks have an outer layer, cementum, around a thicker inner core, dentine. By carefully carving the stave from the junction between these layers, the makers crafted a stave that was half cementum and half dentine. The junction was a weak spot that could be eased apart with blades and small wedges, bisecting the cylinder along its long axis. The hollowing of two halves took commitment and, judging from the result, great skill in creating two thin-walled half tubes from a solid column.
Before splitting the ivory, they cut regular deep grooves down the two sides, perpendicular to the axis of the column. These marks guided the flute’s reassembly once the halves had been hollowed out. Tree resin and animal sinew likely held the pieces together. The result was an airtight fit, ready for the addition of beveled finger holes and a notched end for human breath.
Even after breakage and burial for forty millennia, the flute is an impressively precise construction, its halves fitting snugly, notches aligned. Its thin walls give the illusion of coming from a natural tube, like a bird bone, belying the labor that went into its production. The flute on display here is the most complete of the four mammoth-ivory flutes so far unearthed from the region. Tool marks on the fragmentary remains of the others indicate similar methods of construction.
Life was undoubtedly hard for the makers of these first-known instruments. They lived just north of the glacier-smothered Alps and south of the ice that covered the north of Europe. Animal remains from that time are creatures of the tundra, cold steppes, and mountains: woolly rhinoceros, wild horse, ibex, marmot, arctic fox, arctic hare, and lemmings. Pollen and remains of wood in caves show that vegetation was mostly grasses, sagebrush, and a few boreal shrubs and trees. Every bite of food, stick of fuel, and piece of clothing had to be wrested from a landscape often snowbound and always cold. Yet these people devoted the highest forms of their technologies to making music. The flutes, the mammoth flute in particular, emerged from the application of the most sophisticated craft possible at the time. Their work evinced deep understanding of material properties and skillful use of tools. Soundless, solid animal tusks were transformed by human hands and imagination into hollow, multipitched wind instruments. Precisely wielded stone tools carved voids, spaces where human breath could enter and reanimate the dead.
