LIKE MANY, I like the sound of birdsong and I like melody in
my music; it makes me feel well, happy, good, contented, relaxed and a whole manner of other positive emotional accolades. However, in contrast, there are certain sounds that, for some reason, set me, and probably many others, on edge; they somehow have an impact on my behaviour that seems to be out of proportion and irrational. The discordant, internal tempest of a vacuum cleaner, the violence of a food mixer, the pointless drone of a leaf blower, chainsaws, drills – both drills used for DIY and for root canals – and the scraping of flat-footed flip-flop wearers… they all get to me in a way that seems hard to fathom.
There are medical conditions recently recognised which are associated with sounds. Misophonia, for example, is when a specific sound is associated with a meaning and it elicits a negative emotional response in the sufferer, while hyperacusis is a negative reaction to a sound due to that sound’s specific qualities, its tonal range or frequency. While I suspect that I’m not a clinical case of either of these conditions, this does confirm that certain sounds and frequencies can have an impact on emotional states.
The symptoms, if they can be so called, manifest themselves for me in the form of a deep anxiety, a feeling of unease and being on edge. Recent studies into the qualities of some of the sounds that humans find universally disturbing or distressing, such as breaking glass, microphone feedback and the good old fingernails down a blackboard, have revealed an interesting link between the sound-processing auditory cortex of the brain and the amygdala – a part of the brain associated with emotional responses.
In addition to this, many of the sounds that trigger these neural pathways are those that contain multiple frequencies of discord which fall within a specific part of the audio spectrum between two thousand and five thousand hertz. I don’t think this is an accident. Some suggest that the alarm calls of chimpanzees and gibbons have many acoustic qualities that fall within this range and that this effect, known as saccular acoustic sensitivity, explains our reactions – they are some kind of vestigial, emotional, reflex response to a long-lost ancestor.
While this is purely subjective on my part, I wouldn’t mind betting that many of the distress and alarm calls of other birds and mammals contain a large portion of their sound spectrum in the same range. We also touched on this a little when we were talking about choosing clement weather conditions when embarking on a first night walk. There is a climatic influence on our emotional state: the sound of a windy day, a confusion of interfering audio chaos and background noise, means that somewhere inside we feel vulnerable; one of our main senses is effectively compromised.
At the other end of the emotional response to sound, we have positive, peaceful, soothing sounds – we have music and we have birdsong. There’s a lot of debate as to whether birdsong is music, but the point is that listening to birds vocalising, proclaiming their territory, is one of the most popular ways that we engage with our auricular senses in nature. We need birdsong, even if we don’t notice it on a cognisant level. Birdsong seems to punch right through to our deep subconscious, in much the same way as that food mixer. The background music of nature, the skylark overhead, the song thrush, the countless unseen warblers in the bushes, they all add a flavour to the air, they are the seasoning of the seasons, by their own rhythms they let us know where we are in time and space and when a bird is in full, unbashful song, everything feels right with the world. Your amygdala is happy, and your emotional space is a positive one.
There is probably some deeper, biological common sense at play here as well. Studies have been conducted that show that many birds listen out for the alarm calls of others. This is something known as heterospecific communication; birds (and other animals) effectively eavesdrop on the conversations of other birds and animals and act accordingly. Some learn to associate a particular sound uttered by another species with, say, the presence of a snake, a cat or some other predator, while others have been shown under experimental conditions to elicit predator-avoidance responses or distress associated with the presence of a predator even when played a recording of an unfamiliar species. This is a behavioural stimulus often exploited by birdwatchers who want to get a look at a bird sitting in dense vegetation. ‘Pishing’, as it’s referred to, is a tried and tested abuse of a bird’s amygdala.
It’s possible that there are certain acoustic qualities that many alarm calls share and possible that they’ve evolved together as a kind of cline of similar responses which benefit all the members of a bird community. Given this, it’s not such a far leap to assume that in the ‘wild’ we did the same. I don’t believe we’ve stopped doing it; it’s just that we’ve lost touch and have misplaced the meaning and the significance of these natural sounds.
If you own a parrot, or another cage bird, one way to stimulate it to take a bath is to turn on a vacuum cleaner. It seems surreal, but the sound of the Hoover contains the same maelstrom of sonic chaos as a thunderstorm with its tearing wind and ballistic raindrops drumming on branches and splashing off leaves. It’s nature’s way of telling the birds to get a little bit of personal hygiene in and have a moment of plumage maintenance. The birds in your garden do the same, although, to be honest, I’ve not tried the vacuum trick on them yet.
It’s possible that I’m also doing the same, subconsciously picking up on the harmonics within the chaotic noise of air, dust and motors that remind my brain of a long-lost survival strategy. While I don’t run off and take a shower the moment my wife decides to run the hoover around the house, it does put me on edge, as if I were outside experiencing a rainstorm or a gale. My inner animal feels vulnerable and has to up its game, the body on high alert; the fight-or-flight response switch has been hormonally tripped and I’m on standby.
But back to the birds: all of us, probably subconsciously, use them as a measure of the state of the world, as remote sensors. Their own highly evolved language is something we are probably all sensitive to; we use their emotional states to extend our own awareness of our vicinity.
When we hear a wren singing from the bushes at the side of the path, we are in some way reaching out with our perception, hijacking it for our own purposes. If this isn’t making any sense to you, imagine what happens when the wren changes its tune: it changes how you feel. It alters a little piece of you somewhere, a different pattern of neurons and an alternative sensory pathway is triggered. The alarm call of a wren is harsh and scolding – the dissonance and discord grate on our sensibilities, they put us on edge.
Suddenly, the music of song is gone and we’re back to that discordant vacuum cleaner. We’re listening in to the dialogue – something has disturbed that wren. It might be nothing, but in a wild, complete ecosystem it might just as equally be something. Once upon a time, not all that long ago, when an unseen bird in the bush abruptly stopped singing, it might have meant the presence of a bear, a wolf or a snake. The distinctive qualities of this sound put part of us on high alert, and at one time, hearing and correctly interpreting these particular sounds could be the difference between life and death. We are all connected by these sounds, those we make and those we perceive, it’s a web of living pressure waves being simultaneously emitted and received.
A chorus of birds singing from their territorial song perches, crickets playing a similar musical amour in the grass, frogs in the belching throws of courtship – the positive sounds of aliveness, the hubbub of life getting on with living – whether at the forefront of our minds or buried in our subconscious, these tell us that there is nothing disturbing them or their prime reason to be alive. To procreate is now priority. It’s a system of positive feedback which loops each life, telling others that they’re able to get on with it. However, if a threat, or even the suspicion of one, makes itself apparent, then the acoustic qualities of the environment change. Songs are stopped. Like the string section of the philharmonic orchestra all simultaneously dropping their bows, the symphony is disrupted. Sex is no longer priority any more, it’s been pushed to second spot by a need to live and to survive in order to have sex another day.
It’s nature’s incessant repertoire that we need to aim to tune in to. Birdsong, or, for that matter, any animal song, is so much more than an audio clip or a phonetic tag in a field guide by which to make a positive identification. It’s a means of embedding ourselves via our ears into nature’s dialogue, of becoming a silent part of the phonic appreciation. Even the vegetation and the geology make their own mark on the acoustic signature of a place; they have a direct influence on the ambience.
Being acoustically aware is an almost immediate fix. Your ability to slide into obscurity as far as the environment and its wildlife is concerned means that this act, simple though it is, is also one of the best ways of achieving complete immersion and awareness. In most cases, to be able to hear a bird is to be able to see it.
I would say that over 90 per cent of all the birds I experience in my life I first locate with my ears, which makes me question why we call it birdwatching at all. As part of a recent job for the RSPB (Royal Society for the Protection of Birds), I was employed to find the nests of a rare bird called the ring ouzel. To find a nest of this medium-sized songbird in a relatively large-scale upland landscape, you first need to find the birds. Nature, for obvious reasons, doesn’t make it easy for you to locate its pride and joy. You don’t simply stumble upon a nest.
Although these are birds of open landscapes, which makes them sound easy to find, the places where they breed are often quite complex habitats, with lush forests of fern, boulder fields, fissures and crevices superimposed over a curvaceous topography of broken ground and hillsides. There can be lots of dead ground conspiring against your visual senses.
All birds have to, at some point, break with silence. Part of their daily routine is to announce themselves to the airwaves with sound; an essential part of pair bonding, territorial advertisement and a variety of other things.
When they do, if you know what you’re listening out for, that is when they give away their presence. When you’ve located them, assuming you’re listening and looking at the right time of the year, they will eventually lead you to the cup of moss, grass, roots and stems around which the activity of the birds revolves for the next three or four weeks.
So vital were my ears for this task that I can honestly say that of the hundreds of nests of this bird that I’ve peered into over the last few years of this fieldwork, all but a few, which I can count on the fingers of one hand, have been located because my ears found the birds first.
While sounds are omnipresent and always there for the listening, during the process when you’re training your ears, it’s sometimes a good start to simplify things. Eliminate some of the confusion, strip the soundscape down and consequently, by removing some of the clutter, you’ll make it easier for yourself.
If you want to interpret bird, or any other animal, vocalisations then there are a few pointers on how to get the best out of your ears. For a start, sound quality is best when the air is still and cool. When there is no air movement, items such as loose clothing, hoods and straps are not being continuously buffeted around, creating a distracting noise that competes with the sounds you really want to be hearing. If the wind speed is high enough, then it will create enough turbulence to produce its own music.
If the wind is blowing through vegetation, it sets in motion a cascade of other phonics as leaves and stems rub, rattle and vibrate, all adding to a confusion of sounds, and that is exactly what it is. With so much incidental sound being generated around you, you miss out on the subtler parts of a bird’s vocalisations. It’s like hearing a tune on a quiet car radio, but not being able to hear the lyrics.
Back to my ring ouzels: they have a strident monotonal trisyllabic note that carries through all but the most violent windy mountain turmoil, and if you hear this, you may be forgiven for thinking that this is the bird’s song in its entirety. However, listen to the same song on a still day, and you get to hear the extra features – a quieter, complex and subtle warbling song, a reedy melody sung almost under its breath, which to me sounds like a song thrush in a glass bottle with a blanket over its head.
It is also best to listen for sound first thing in the morning. There are several reasons for this that go beyond the fact that if it’s birds you’re listening to, it’s during this time of the day, before it’s light enough to start to feed, that most species make use of the time to update their neighbours and remind them who’s who and who’s where. Like many of your other senses, your ears work at their best early in the day, up until mid-morning, when your body is fresh and alert; as the day wears on we get tired and our ability to concentrate wanes. The cooler the air, the louder the sound seems to be. Theoretically, sound waves should be transmitted better in higher-energy, warm air. But in reality warm air usually generates other manifestations that hinder and obstruct sound transmission.
Sound waves don’t just travel from the source to you, they dissipate like ripples in a pond in all directions; those that head up, and would normally be lost to the land, dissipate into the atmosphere.
So there are lots of very good reasons for you tone hounds to be out and about early in the day. These advantages are further justified by the fact that the earlier you are out, the quieter the human world will often be; the hustle and bustle of the day’s activities hasn’t yet started up, meaning you’ll be able to wander the acoustic landscape pretty much by yourself.
Go beyond the book
Listening to birdsong is one of the most popular ways in which humans engage with the natural world of acoustics. Birds are a very useful way of schooling yourself to be aware of the natural soundscape, as what you learn when listening to birds can be applied to any other scenario where the ability to listen and interpret the world by sound presents itself. Don’t be limited to birds; while they are stimulating enough, the same techniques and approaches can be applied to almost any group of animals, from bats to bush crickets.
Wherever you are, there will be birds, if not singing then at least calling, making them an excellent and accessible subject to focus your ears on. From Burns’s ‘sweet warbling wood-lark’ to Thomas Hardy’s ‘Darkling Thrush’ who flung ‘his soul upon the growing gloom’, birds and their song have inspired people for millennia. Poets love them; and their songs are deeply embedded in our culture. They weave and thread their way through our words and music, much as the notes, emanating from a nightingale’s silvered syrinx, weave through the hazel and briar.
Listening to birds and being inspired by their song is a pursuit that has always fascinated and engaged man, whether naturalist or not; we’ve long cherished their vocal abilities and harboured the notion that their songs contain secrets, in a language the sense of which is long lost to us.
Like Wagner’s Siegfried, who drank dragon’s blood in order to understand the woodbird, we as a species yearn to find significance in the song of birds and a profound connection with nature in their mystical music.
Get beyond the prose, the poetry and the imagined music and there is, of course, much more meaning and plenty of secrets to be revealed simply by the act of listening, really listening. No dragon juice is needed, just your ears and your full attention.
However, when you’re learning animal sounds, especially bird songs and calls, it can seem a little daunting. Their voices and all the subtle sonics contained within their vocabularies don’t translate very well into our own limited alphabet. As a consequence, they are very difficult to communicate or to describe with any accuracy and because of this they can also be quite hard to remember and learn.
When we seek to identify a bird we’ve seen, it’s a relatively easy thing to do; after all, we live in an age of numerous high-quality field guides. It seems that, wherever you are, there is nearly always a very good printed resource that will help you unravel what it is you’ve just laid your eyes on. A quick glance at some half-decent graphics and you’ve got all you need, assuming you got a good enough look at the bird in the first place. A lesson I soon learned as a beginner was that the same can’t be said for sound. You can’t easily visually represent a call or song; if you’re lucky, field guides, if they attempt it at all, will give you, under a limited range of subheadings (song, call, alarm call), a subbed-down handful of attempted phonetic descriptions.
The problem with these is that the sounds that are written depend very much on the interpretation of the author. Some birds have regional dialects just like humans, but an author has his or her own accent and individual way of hearing their own voice. So one person’s too-whit is another’s kee-wick, kewick, kvik, ae’wick or even kivik, to use and quote the call of the common and widespread tawny owl from a selection of field guides sitting on my shelf – and this is a bird sound that is embedded in our popular culture and one which is the go-to sound effect to use in any TV drama night scene. It’s somewhat surprising to see so much variation, even if the sense of the call is fairly clear in this instance.
The same exercise repeated for the common buzzard gives me peeioo, piiijay, pee-oo, mew, me-ooow and peee-jah, and then when we start getting into birds with quite a complex sound signature we start losing the plot: dlui-dlui, dlui’, dlui’, dlui’, dlui, didlui; tit’tit’tit’toodle’toodle, toodle, t’loo, ti-loooi, tlootlootloo; lee, lee-lee, leeleeleeleelülu… ee-lü, ee-lü, ee-lü; ee-lueelueelu… tluee, tluee, tluee, vi vi vi tellellellell… goes the woodlark in just three of these reference books. The sounds we hear and how we convey them in our own languages are highly subjective. It’s just not possible to represent the multiple vibrations and the simultaneous overlap and harmonics that can be created by the various membranes in a bird’s quivering breast.
So you start to see the problem here. It can get so complex that we might be tempted to give up on our ears and revert back to our primary sense. In some cases these descriptions are a help, in so far as they give us some clue as to the various qualities of the pitch, tone and rhythm of a call or song, but in many cases they can throw us off the trail when it comes to seeking the identification of a species, and just by relying on these as references, in the same way we use the illustrations, we can be missing out on some acoustic treats by simply not allowing ourselves the time to absorb the sounds and listen to them properly.
You can sometimes identify a pop song from its beat and bass line when you hear it through a wall or issuing from a car that passes in the street; the same skill set can be applied to what it was originally intended for. If you really listen, you can begin to pick up on the nuances of the natural music and the more you engage, the more familiar it gets and the more deeply you become entangled in the dazzling and beautiful complexity of it all.
There are plenty of resources out there to help you interpret what you’re hearing and of course we do live in an age of multi-media digital technologies, some of which can be extremely helpful at guiding you through the technique. There are now websites, apps and e-books that are not constrained in quite the same way as the more traditional field-guide format, and many of these now include audio. But the problem still remains: how do you represent such a diverse vocabulary in an easy-to-work format? You can’t; even the best of these multi-media guides usually give the most common or frequently uttered refrains, three or four at most. While the dedicated audio apps and websites are excellent once you’ve become immersed and have started to build up your experience, they are nothing more than a collection of interesting but disjointed sounds and noises for a novice.
In some way, you need to build up your own internal understanding of these sounds. They have to have a context and you need to start developing an understanding of syntax, otherwise they’re just that, meaningless sounds. Listening and reaching out to the sound, going to the sound in your mind’s eye, is that context. This means analysing the various qualities of the sounds and thinking about how they are generated. The sense and the syntax is built up slowly over time, as you get more intimate with the environment you both share.
Birds can make noises by using many different parts of their bodies. Understanding the sound-making mechanisms, the instruments themselves, can really help you picture the production of the sound and even help you describe and memorise it for future recall, all part of the immersion process.
Snipe use physical vibrations set up over their outer tail feathers; owls, sparrows and many others click their bills; hummingbirds rattle their wings against their tail feathers; and bustards stamp their feet – these are known as sonations. However, birds normally communicate with each other using their voice, or, more precisely, their syrinx. Named after its resemblance in shape to a pan-pipe by the same name, this, the primary sound-production organ of birds is located just after the main trachea splits to form the two bronchi that lead to the lungs. By modifying the diameter of the bronchi by either relaxing or constricting, the passage of air flowing either into or out of the lungs is regulated (think letting air escape through the neck of a balloon) and these membranes of the syrinx can be set in motion, giving a series of complex vibrations which together create what we hear as bird noise.
The bipartite structure of the syrinx compared with the relatively simple single tube-like arrangement of the human larynx means that two or more separate sounds can be produced simultaneously as the air passes over them. It is this complex device that led Pliny the Elder, when referring to the nightingale’s song, to write: ‘There is not a pipe or instrument in the world that can produce more music than this little bird does out of its throat.’ The same sentiment can be applied to most other bird songs. It is these different vibrations set up by several simultaneously resonating membranes that give the depth, modulation and harmonic richness and complexity of many bird songs and why it is so difficult to impersonate them with any degree of accuracy.
Now you know the mechanics of the instrument that birds play on, you can almost start to visualise the internal workings when you sit and immerse yourself in the particulars of the sound. It’s what I do every spring morning at about 4 a.m. when the blackbird in my garden fires up. As soon as those chocolate tones hit the day and wrap themselves up with the dawn, I’m following them, in my mind’s eye, back to source.
I’ve never seen a syrinx in action with my own eyes (although there are some fascinating X-ray films of birds singing online which show the musculature contractions and contortions of the bird’s entire body as it pumps out the sound), but I allow myself to feel the very physical origin of the pulse, the energy given by the bird to the virgin air, its warmed breath a vapour on the atmosphere. I imagine how the bird is handing over its very own body tissues to the music it is making. I try and get inside, to see the membranes of this magical musical instrument as they relax, tighten and pulsate with every inward and outward breath. I also think of its significance. What is it that this bird is declaring to the world? It’s a woodwind instrument with an effort and intent very easy to underestimate in our own thoroughly different visual world.
When a wren sings its 740 notes a minute, it can be heard in real terms some five hundred metres away. Imagine doing that. Scale it to the relative size of the wren, and to our own body size, and you’re going to have to put more than just your heart and soul into your cry if you are to be heard five miles away! Various studies have shown that the metabolic energy cost goes up by 20 per cent in a singing bird like the greater reed warbler, even more so if it’s a species that has to expose itself to the cooling air by singing from a song perch. Some birds will sing for lengthy periods of time too. The ‘little bit of bread and no cheese’ song of the small finch, the yellowhammer, can be repeated over three thousand times a day, and what before was just a nice sound suddenly sounds exhausting – it’s not a mere musical performance, this is a physical effort of Olympian standard.
When a bird sets the air around it vibrating, it is sending pulses of energy out into the environment. These waves of sound are sculpted by a bird’s syrinx and these species-specific given qualities and characteristics allow us, if we get a good listen to them, to understand not only what made them, but also what their intentions are. It is this greater comprehension of each sound and the soundscape at large that we are aiming for here.
When you’re listening to bird sound, there are various ways you can break down and understand what you’re hearing. We’ve already covered what sound is and its pitch and frequency, now we can look into the qualities of natural sound and how to interpret and decipher what we hear.
The most basic characteristic of a natural sound is its tone – this is a broad-stroke term which refers to the general character of the sound, described in one of the best books on the subject of birdsong and vocalisations, The Sound Approach, as being the equivalent of jizz. This could be the warm, rich tones of the blackbird, the thin, high song of the dunnock, the piping of a redshank or the moan of a puffin. To the tone, you can add a bit of texture: to the description of the blackbird’s song you can add the adjectives ‘smooth’ and ‘round’; ‘reedy’ and ‘shrill’ suit the dunnock; and a ‘throaty groan’ and ‘growl’ suit the puffin. This texture is something we can describe as a sound’s timbre. It gives the sound a spectral quality and brings it to life.
We’ve touched on the personal variance and the limitations of our sense of hearing already, however, and rather than get hung up on what you can’t hear, let’s look or listen to the sounds in a different way. Most natural sounds are not pure. One way of clearly visualising the qualities of a sound is to record it and play it back through sound-analysis software, to create something called a sonogram or, more accurately, an audiospectrogram. This is a simple, graphical way of representing sound, which plots frequency against time. It turns sounds into sights.
With time running along the horizontal axis, while the vertical axis represents the frequency, the higher on the graph, the higher the pitch of the sound. A pure, continuously sounding tone would be a single frequency represented by a straight line that would run with time from left to right. A bird call or song is very different; the sounds goes up and down, producing peaks and troughs as the frequency of the call goes up and down, changing pitch.
This may seem way off topic for a book about ‘rewilding’, but in this case, by stepping back briefly into the technological world, it is possible to give yourself a greater understanding of what you’re perceiving. I know many people, pure birders amongst them, who simply don’t get on with sonograms, but who learn to read them, and I think you’ll find them a really neat and beautiful way of ‘seeing’ into the depths of some of the sounds you are hearing. There are plenty of examples of recordings online where you can listen to a bird vocalisation in real time and see the shape of the trace it makes. You don’t even have to use your imagination. Choose the song of a bird you are likely to hear in your own garden or patch, and every time you hear it, try and visualise the sonogram. In time, you’ll find it makes a lot of sense.
It might be useful to have an example of how useful sonograms can be for helping you ‘read’ the sound waves. Take the simple contact call of a warbler: many of the ‘green warblers’, while they have a signature song that almost everyone will be able to recognise as being different – a chiff-chaff, for example, sings its name, while a willow warbler gives a lovely rich descending cascade of notes – if they’re not singing, but are making their contact call, then you might feel you’re in trouble. How on earth are you to get to the bottom of this if the bird is saying hweet unhelpfully at you and when you look at your field guide, it seems that both species have a contact call which is described as huit or hoo-eet?
Have a look at the sonogram for each species and it all makes sense. The sonogram of the chiff-chaff has depth to it caused by several harmonic layers. It also has a steeper rise on the main call note, while the willow warbler emits a simple sound less in the way of harmonics and so purer in tone, but it stays on the first syllable of the call for a fraction longer, giving it more of an obvious upwards sweep. The point of the sonogram is that it can transcend our difficulties and limitations in discerning and describing what we are listening to.
I find it quite handy to try and picture these sonograms as best I can when I hear birdsong. I find it a useful way of visualising the sounds I’m hearing. Obviously, the resolution of the human ear has a limit and while we can often get the overall gist of what’s going on, the reality is that the often-overlapping modulations that give a sound its depth and texture are difficult to differentiate; you can describe the overall sound but it’s sometimes a bit of an ask for our ears and brains to separate the elements. However, remove some of these harmonics and you’ll notice the difference, even if you can’t tell what, specifically, has given it a certain quality.
As well as being a way of helping you visualise the sounds themselves, sonograms can help us understand other aspects of natural sounds which give us a scaffold of visual shapes on which to pin the unique qualities of a bird’s song, a bat’s chirp or a cricket’s buzz.
I know many birders and naturalists who have far-from-perfect hearing for one reason or another and while I do meet those who can no longer hear clearly birds that sing or call at the very extremes of our hearing range, such as the wheeling tittering song of a goldcrest or the low ‘boom’ of a bittern, most can still pick up the sounds of birds which contain a more complex range of frequencies. Take the piping call of an oystercatcher: its often-repeated phrase ‘my feet’ is a common sound of shore and salt-marsh oystercatchers. If you were to record this song and then construct a sonogram of it, you would roughly get a pointed shape that looks a little like an inverted ‘V’ with the trailing edge being a little rough and less steep. You would also notice that you don’t just get the one trace.
There are several of these inverted ‘V’s stacked above one another, as if mirroring each other. The lower one is called the ‘fundamental’ and it sits around about 2 kHz; those above it at 4, 6 and 8 kHz, while quieter, are still there and they very much add to the sound. Each of these layer stacks is called a harmonic and occurs at multiples of the fundamental; these give the call depth and make a sound seem richer. The opposite is if you have many traces that don’t occur at regular intervals but are still stacked above each other. In time you get sounds which are scratchy and buzzy and which by the physics of sound can be described as less harmonious. Just to make things even more wonderfully complex, some birds can have harmony and disharmony going on at the same time!
If your hearing isn’t very good at one of these pitches, how you hear the overall sound will be different to how an eight-year-old hears it, but you will still be picking up some of the overall properties, the rhythm, tone and texture of the sound. So while you may feel that if you are coming to this later on in life, you’ve missed out on the opportunity to hear and connect with bird (or any other wildlife, for that matter) sounds, you don’t have to worry too much, you just have to listen to these natural noises your own way.
The timings within or between a bird call or song can be crucial to identification too. Sometimes it helps to think of those sonograms again. The call itself can be composed of several sounds strung together, the rate at which these phrases or notes are delivered and the tempo; the way these are spaced out can all be measurable by counting and timing. The difference in any of these numbers can alter the overall feel of the sound and can therefore alert those who are listening to a different species, a different context or, sometimes, an individual.
An example of this when applied is found in the telling apart of the songs of reed warbler and sedge warbler – two birds that drove me mad as a beginner.
Both are denizens of habitats that are almost impenetrable to the human eye. The most you have to go on is their music emanating forth from somewhere deep within the complex and dense reed beds and the scrub that surrounds them. To my untrained ear, it was a struggle. Tonally they can be very similar, they lack unique signature phrases or hooks that I could memorise and hang on to and, added to the fact that they also are pretty good mimics of other species of birds, including each other, I was thoroughly confounded and frustrated.
When I was told to listen to the beat, suddenly it became a breeze. The reed warbler, no matter how eccentric its improvisation, has a constant, rather plodding tempo, repeating phrases one after another, as if it’s a little bored about showing you its entire repertoire. The superficially similar sedge warbler is much more sprightly and syncopated. It is the virtuoso of bird jazz. There are other differences, but for me this clinched it. Add to this the image of the bird, in case you get a snatched glimpse, and you will see that the plain brown conservative tones of the reed warbler go with the character of its song, while the more dashing and well-marked sedge looks like the sort of bird that might cut a dash with its funk. This anthropomorphism, the storytelling, the visualising, all serve to connect different regions of the brain. This is a well-known memory trick and by linking the bird’s appearance, its rhythm, a visualisation of its song and a story, you are tying them all together to create a memory web with multiple references to the context in which it is performing. It’s a process that speeds up the accumulation of experiential knowledge which you can fall back on and recall at will.
Many species, including birds, frogs, grasshoppers, geckos and cicadas, will alter the rhythm of their songs depending on their emotional state. When a potential mate is close by, or a rival male, they will up their game. It’s a show-off or a showdown. A midnight pool of calling tree frogs in the Amazon, while noisy, is also a scenario where the males are playing a risk–benefit game. It’s a trade-off. You’re singing because a female could be listening in to your impressive voice, but, at the same time, your song is letting every frog-eating predator such as a false-vampire bat know exactly where you are squatting in the shallows. The hesitation and the sense of poker jeopardy are almost tangible, until, that is, a female actually arrives. Suddenly the soundscape is turned up a notch, the night is filled with a loud and more rapid pulsation of sound, the jam is pumped, the rhythm has sped up and the mating game is on.
The same happens in most walks of life: songbirds, cicadas and crickets will have sing-offs and increase the complexity and volume of their utterances in order to outdo the competition – even spiders will engage in a faster drum solo.
I recall lying awake in a thatched lodge somewhere in the Amazon one night and hearing a strange vibration, the pulse of a hollow tapping sound, like distant woodpeckers (which, incidentally, can be told apart in some cases simply by the rhythm and tempo of their drumming). Initially, I was thinking it was beetle larvae or termites communicating with each other in their burrows within the building’s timbers, but I became more interested when I noticed the pulses were changing not only in volume but in their overall vigour; something was investing more and more effort in the sound production, and also in the rate of the pulses and the speed with which each individual beat was delivered. Eventually, curiosity got the better of me and I turned on my torch to discover, above my head, a male pink-toed tarantula busy trying to get the attention of a female who was being lured out of her sock-like silken lair. The more interest she showed in him, the faster he tapped out his message with his modified front limbs called palps – a mixture of anticipated love-making versus desperation to be clear about his intentions as a prospective mate and not as a potential meal.
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The best thing about being able to really listen is that you don’t necessarily need to be able to ‘spot the artist’ and identify it from its music to appreciate and extract a meaning and significance. It is only when you need to share or communicate this information with others that this ability to identify what you’ve heard becomes more important. This is why learning birdsong needn’t be so difficult. Don’t get hung up on an inability to put a name to a face. After all, you don’t need to know the piece of music or, indeed, the name of the composer, conductor or even the instruments in the orchestra to appreciate the music. However, if you do start to really listen, your natural curiosity will kick in. As you become more immersed in the listening, you’ll start to notice details; nuances and then the names will start to become associated with the experience of the sound, and you will start to connect deeply with both the sound and the sound makers.
Open your sound flaps
If you look at the ear structure of any animal for which sound is the dominant sense, you will in most cases notice a sizeable flap of skin, the pinna. This external ear in these species is highly mobile and can be trained on the source from which a sound has emanated. Sets of tiny paired muscles called the auriculares allow the ears of many mammals to be drawn up and laid down as well as rotated. These highly mobile flaps act a little like ear trumpets but, being separated on either side of the head, they can be used to give accurate positioning and, just like the binocular vision of forward-facing eyes, the ears can judge the distance of the source as well. While we cannot move our ears like Stan Laurel (although some of us have a vestigial genetic musculature that allows a little bit of movement) we can all enhance their ability very simply. Just by placing your cupped hands behind your ears, you can amplify and enhance the sounds of particular interest as you face their direction. This is especially effective if it is in a noisy environment.
For example, try to discern the song of a territorial dipper singing from the top of a rock in a roaring riffle and you will struggle, even if you’re looking directly at it; at best the odd note and phrase breaks through before the rest is snatched away by the singing river. But cup your hands behind your ears while continuing to focus on the bird and the song jumps right out of the water at you. In truth, while you may be catching a little more of the sound, you’re not really enhancing it, you’re just cutting out the extraneous ones that are coming from other directions. You’re focussing the sound by catching it from a smaller area with your hands.
Electric ears
As you’re beginning to realise by now, the art of listening is almost wholly tied up in the ability to focus on sounds themselves, to invest time in finding and concentrating on them. The underlying physics is the same, capturing sound waves and converting them into electrical signals. To take all you’ve learned so far to another level is possible, but again we have to step away for a moment from the natural instruments of detection we were born with and once again enter a world of technology. As before with the sonograms, this process allows us to gain an even greater understanding and if ‘insight’ isn’t quite the right word, then let’s call it ‘inhearing’.
The technology and craft I’m talking about here is that of sound recording. While I don’t intend to go into any great detail on this, it is worth a mention as it is a very effective way of gaining a greater understanding of the bioacoustics world. If you really get into recording natural sounds, then the next step is to create your own sonograms – it might be a step too far for some, but the technology is often much closer than you think. Armed with a mobile phone and a microphone you can make the next leap off into the swirl of natural phonics, a process that can help no end in the interpreting of everyday sounds.
In the same way that a camera records what we see and works very much like our own eyes, sound-recording equipment is in essence no more than an electric ear on the world. A parabolic reflector is a funnel, a large version of your outer ear, while the microphone is analogous to the middle ear, turning the sound waves into electrical signals just as your own ear does.
Admittedly, it’s a bit of an investment, but by making it you can take a step further into the world of natural acoustics and sound exploration. It also allows you to record and analyse it, even collect it, so that you can make a reference collection, just as you might collect photographs of animals. In this way you can learn and develop your understanding. It might seem a bit bionic but the ability to hold on to what would otherwise be in-the-moment, ephemeral transmissions gives you a chance to repeat and decipher the moment. To me the ability that these sound recordings can give you is akin to some kind of magic and one of the few justifications for using the technological world in your own rewilding adventure.
The advantages of a parabolic reflector are that it has the ability to capture sound over a wider area and direct and focus it on the microphone in the centre. Then, by listening to it live through headphones, you are effectively achieving what you did with your cupped hands but in a way that eliminates even more of the extraneous sounds. Because of the large dish, you’re also able to hear many of the lower-pitched sounds more clearly as well as some of the more subtle sounds that are easy to miss.
While we’re on the subject of ‘electrickery’, there are many more ways to listen in on nature and sounds. You can even achieve an audio perspective on the completely secret world of creatures that operate outside our own pitch range – devices such as bat detectors can step down the high-frequency ultrasonics of bat, shrew and even various parts of an insect’s acoustic world that would otherwise be well out of our range.
Standing with your eyes on a crepuscular sky, with bats streaming out of a cave entrance like a million motes of smoke, is spectacular, but somewhat two-dimensional; you’re not getting the full story, as they operate in an acoustic world beyond our own. Flick the switch on a bat detector and your ears are filled with pulses and popping, smacking and ticking, a secret world of sound. Flick it off again and you are plunged back into our own silent world, incredulous and disbelieving that, right now all around you, is a soundscape outside our particular take on reality. While this is real time, you’re only getting a translation of the sound, not the actual sounds that the bats make and hear.
While it’s often thought of as a bit daunting, just by the investment of a little time, like so many skills, enjoying and interpreting natural sound can be made so much easier by breaking it down. First of all, find ways to enjoy the experience, this is the most important step. After that, the enthusiasm gets going and your natural curiosity, that innate ancestral ‘wild’ you, takes hold of the reins. Believe that you’re designed to listen and work out the wild world of bioacoustics and you will succeed. Remember, your ancestors (not that long ago in biological terms) would have made a living by knowing and interpreting the vibrational messages on the air. While you can delve as deep as you like into the physics and the science, the gadgets and the gizmos of sound, I make no apology for the technical descriptions given in these chapters. The one takeaway from all of this is that you don’t need to – this is just a helping hand, a way that might connect some.
Just learn to listen and you will hear a world of previously hidden meaning in which there is a beauty and a deep connection between you and the natural world.