Taiwanese Bush Warblers imitating garbage trucks: a mutual affair?

Mark van Tongeren

An ear to Taiwan[1]


A typical sound of Taiwan (as well as the People’s Republic of China) comes from a waning tradition: street-vendors selling puffed-rice-cakes, whose notice is a loud explosion that can be heard several blocks away, thus warning residents of their arrival. Their characteristic bang and other street vendors’ calls are disappearing, while the door signals of convenience chain stores have become the new signal to announce the availability of food and other goods. Essentially every client entering and leaving a convenience store sonically advertises the place: two public sounds for each purchase. Another popular sales technique in Taiwan are megaphones with pre-recorded slogans, placed inside or outside a shop, which make repetitive non-stop advertisements, typically on a loop of about five seconds. They do not seem to particularly encourage or discourage potential buyers from shopping.


During a workshop entitled “The Art of Listening,” which I led in the mountains near Hsinchu, “Taiwan’s Silicon Valley,” workshop participants also noted recent influences in the soundscape. Moving from global to focal listening (Oliveros 2005), they observed natural sounds, audible signs of human activity, their own sounds (breathing, coughing) and, finally, their own listening. When discussing how this soundscape might differ from the one thirty years ago, we concluded that most human sounds would have been absent. The most obvious impact results from the increase in powered travel and use of mechanical tools. The more confronting, and perhaps inconvenient, reality was that the sounds of human voices from the lower valley, one of the most obvious acoustic signals during our exercise, were absent as little as two years ago, when tourism was not yet developed in this valley. We noted the paradox that a growing number of Taiwanese escape the hubbub of the city to wind down and search for quietude, only to find other city-dwellers (and themselves) changing the very land- and soundscapes they visit.

Workshop participants observing the soundscape of the mountains near Hsinchu, Taiwan

Underneath the surface of technological, amplified and auto-repeated sounds in the public and semi-public sphere, one can hear an abundance of natural sounds of insects, birds and mammals. Some of these are found in the city and countryside alike, like the singing of cicadas, which may create a dense wall of sound, sometimes in the middle of residential areas. At other instances, you may be able to hear just one type of insect or frog singing, like these two crickets of the Ornebius species, which I recorded near my home, performing an accidental duet.[2]

insect duetto[3]

The sounds of all these living beings occupy distinct niches of sonic space as regards the time of calling and the frequencies used. Soundscape recordist Bernie Krause coined the term niche-hypothesis for this phenomenon (Krause 1987). Later he introduced a more general term, biophony, to describe the totality of sounds produced by animals, excluding humans, in a certain environment. Two more terms, geophony, to account for sounds of the earth (such as rain, thunder, volcanic activity) and anthropophony, to account for human-originated sounds, were added by Stuart Gage of the Envirosonics Lab in Michigan in a joint project with Krause (Krause 2008). Biophony and anthropophony occupy a common space or interpenetrate each other, creating the hybrid sonic ecologies of human and non-human habitats that are common in spaces occupied and travelled by humans.


There is one particular repeating sound pattern in the combined bio/anthropophony in Taiwan that I now want to focus on. I suspect that I have witnessed a transference of human sound signals to a small group of non-human species able to emulate these signals. In what follows I will describe this unusual case, offer a possible candidate, make a reconstruction of what I heard and contextualize my observations within the emerging field of zoomusicology. My purpose, in trying to reconstruct what I heard and to present it as clearly as possible, is to invite an ever-increasing global community of conscious listeners to keep an ear open for similar cases.

The musical garbage truck phenomenon


All over Taiwan, garbage trucks equipped with loudspeakers make their rounds, up to ten times a week in a single locality, playing tunes that announce their arrival to the citizens. It grabs the attention of most foreign visitors, who do not have such musical waste-collecting services at home. YouTube hosts at least a dozen clips posted by visitors from Japan, America, France, Germany and other places.[4] Two melodies can be heard from the trucks: one is Beethoven’s Für Elise, and the other is rather obscure: few people know its title or composer. Among the Taiwan garbage truck videos on YouTube, the lesser-known piece has more uploads than Beethoven’s. Several American YouTube users recognize it as “ice cream truck music.”[5] This sweeping, Romantic-era melody, with several rising arpeggios, is now as famous in Taiwan as Für Elise is around the world. I do not recall ever hearing it before arriving in Taiwan. Here is a recording of a garbage truck with the lesser-known melody.[6]

The musical garbage truck in Taiwan   

Designed to reach people’s homes at a considerable distance from the stopping points, the garbage truck music is loud and pervasive. The two tunes have entered the collective consciousness of the current population more than any other tunes – at least quantitatively speaking. They thrust themselves onto large swaths of Taiwan’s landscape and all of its living inhabitants. Not only homo sapiens sapiens but also other species have taken notice and musically responded to it, as I observed with a shock one evening while staying in Taidong, one of Taiwan’s more remote provinces.

Animal sounds resembling the garbage truck tune


Late November 2008, I spent some time on the East Coast of Taiwan, taking a break from the metropolis of Taipei. I enjoyed the quietude of the mountains in a homestay not far from the popular hot spring resort in Zhiben (Beinan Township, 卑南鄉), which lay just out of sight in the valley beneath us. One evening I heard repetitions of the unknown tune from the garbage trucks. I was puzzled by some deviations from the normal pattern and paid closer attention. The truck seemed to be making its rounds quite slowly, since its music continued for a long time. Uncharacteristic of the garbage trucks, the melody did not stop after one or two minutes. The sound faded away and resurged again many times. The melody was also slightly slower. Another odd variation was that the melody was incomplete. I then understood that this could not be the garbage truck but must be something else.


Listening more closely to the quality of the sounds, I realized they were not produced by humans but by birds, somewhere in the valley. The portion of the melody they sang seemed almost perfectly in tune and clearly recognizable as a section of the melody. Somewhat puzzled, I believed that I had stumbled upon birds mimicking the sounds they frequently heard in their environment. They appeared to have adopted human musical forms into their song. I stared into the valley, listening intently, wondering what I could do to observe this phenomenon more closely. I had no clue how to try to locate the sound. It could be emanating from anywhere in the dense vegetation of the valley, where investigating by foot was difficult due to the slippery, steep slopes, as well as potentially dangerous due to the darkness and the presence of snakes.

Location in Zhiben where I witnessed singing animals

The following night I heard the melodic pattern again. The son of the property owners was visiting, and I asked him to take me around to try to locate the birds. I gathered they were somewhere further down the valley and was hoping he could show me some paths in the dark that brought us closer. He suggested we take his car, and we hit the winding road down the steep slope, but there were no tracks in the direction where I thought we needed to look. Instead, we went down to the main road in the valley, along the riverbank. We found some stairs leading up onto the slope from there, but they would soon end, not getting us far enough. We returned to the homestay where we followed the paved road upwards on the slope. I pricked up my ears: nothing. We went back to the homestay. And there it was again.


I then decided to try to move down the steep slope through the thick, dark brush to get closer, even though I thought it would be impossible to get close. I did not need to go far. Almost as soon as I set out, it became apparent that the source of the sound was actually quite close to the edge of the lawn. It was so nearby, in fact, that I was afraid to disturb the animals and most likely silence them if I tried to go down. I got as close as I deemed prudent and then sat there, listening intently to the melodic segment repeating over and over again. I was unable to see the sound-makers, but since the voices came from dense, low shrubs, I believed that the source of the sound could not be birds, but must be frogs.

I now noticed that it was not just a single creature that produced the whole excerpt of the garbage truck melody, or a group singing the same tune. This astounded me even more. While I squatted at the edge of the slope, I could clearly hear the sounds come from different directions near me, from various points on a left (north-west) to right (north-east) angle. This was not due to the sound source moving. Several individuals were issuing a single sound each, from a stable position. I am not certain whether the exact stereophonic pattern was repeated again and again, that is, if each animal produced the same tone or set of tones again and again, but there could be no doubt that the melody was shared by multiple animals, each singing a section of the melody in sequence. Each animal may have sung only a single note, a technique that musicians refer to as hoketus.


Summarizing, the sounds I heard from the animals had the following characteristics:


1.   Structured and regular repetition of pitched sounds.

2.   The same pitch sequence, repeated at least a few dozen times and during subsequent nights.

3.   In between the sequences there was only silence, with no other singing (only the same sequence was sung).

4.   The timbre of the animal sounds was pure and sine wave-like.

5.   The timbre and structure clearly evoked an association with bird song.

6.   At the onset, each pitch gradually increased in loudness, then was held for more than a second.

7.   The sequence of rising pitches strongly resembled a part of one of two melodies played regularly (typically five days a week) by Taiwanese garbage trucks, so much so that I felt certain it was an imitation of that sound.

8.   The melodic sequence was not sung by one animal, but produced alternately, hoketus-like, by different animals, perhaps 2-3 meters apart: at close range, the pitches came from different directions each time.

9.  The animal’s singing took place in low shrubs, with GPS coordinates 22.689559 / 121.001498, at an elevation of 250 meters.

10. Time of day was early evening.

11.  Time of year was late November.

Unfortunately, I was not able to figure out in detail how they did it, nor which species produced the singing. It was our last night, and I did not have my recording equipment. I had to leave without a recording and decided to return as soon as I could. A busy schedule prevented me from doing so in a timely fashion. When I visited the place again, I did not hear the sounds. I have returned several more times, hoping to hear them singing again, to no avail.Ever since, I have been thinking about the sounds of these animals, which sang in chorus, in a strikingly organized and repetitive way, a fragment of the prevalent Taiwanese anthropophony. In the absence of any concrete material, I have listened to the echoes of their song in my head, trying to make sense of them. I shall now try to reconstruct in more detail what I witnessed and offer a possible solution to this phenomenon.


Tekla Bądarzewska-Baranowska’s A Maiden’s Prayer

The less familiar melody of the waste collectors was written by the Polish composer Tekla Bądarzewska-Baranowska (b. 1834 or 1838, d. 1861). When she passed away, aged 26 or less, she had written about forty compositions. Her early piano piece – Modlitwa dziewicy, Op. 4 – is her most successful piece and became widely known by its French and English titles: La prière d'une vierge and A Maiden's Prayer. Bądarzewska-Baranowska’s name remained little known during her life and up to today, in fact, even though A Maiden’s Prayer has become a very popular piece for music students around the world. It eventually came to be chosen as one of the call signals for garbage trucks by Taiwanese authorities. The garbage truck version is adapted from the original, having simple waveforms without octaves or chords. Subsequent pitches overlap and follow one another in a steady, relatively fast pace compared to piano versions one finds on the web, like this one played by “ikerisa” from Japan.[7]

The Maiden’s Prayer by Tekla Bądarzewska-Baranowska, performed by ikerisa (Japan)

The portion of the melody that is of interest in the original piece are two arpeggios (broken chords of rapidly ascending notes), because the ascending pattern forms the basis of what I believe was mimicked by the animals. The original is based on two arpeggios, one starting on E-flat, another on B-flat. The ascending arpeggios are repeated in whole or in part several times, with slight variations. In its adaptation for public use on the trucks, the original melody is somewhat rearranged and transposed to another key. The YouTube videos allow comparison of the exact frequencies used on the garbage trucks’ playback-systems in different localities and times. There is up to a semitone difference between lower and higher versions, although a quartertone variance is more common. The two arpeggios may start on G and E-flat or on A-flat and E, with smaller microtonal deviations between them.

Two arpeggios from A Maiden’s Prayer

Page one of the music score of A Maiden’s Prayer

The species I may have heard


Searching for possible clues to the species I may have heard, I began to look for collections of frog recordings of Taiwan. However, I did not find any type of frog that was able to make the sustained, pitched sounds I heard. Convinced that I did hear a group of animals singing in an unusual chorus-like fashion, I recently began a new search with online resources. I started to check the recordings of all the wild frogs and other species I could find in Taidong. While going through Cornell University’s Macaulay Library of animal sounds, a flash of recognition struck me when I came across the Brown-Flanked Bush Warbler. Among the dozens of recordings I had heard of Taiwanese frog and bird species until then, I had not found anything reminiscent of the animals I heard singing. But this one precisely matched the sound quality of the tones I heard coming out the scrub years earlier. The bird produced a steady, sine wave-like tone. It started soft and gradually built up in loudness, then holding a pitch that was quite stable and long, about a second. It was also able to sing a wide range of different pitches during a singing bout.

The Macaulay Library entries, no. 14336 and no. 14337, were recorded in 1966 by ornithologist Sheldon R. Severinghaus, who wrote the following notes:


Locality: Nantou, Wushe, Latitude/longitude: 24.0333333   121.1166667,



What Severinghaus calls “melodious whistle” is currently called “syllables” in bird song studies. There are two types of the short syllabic part, which sometimes consists of two, sometimes three rapid notes. The bird’s “introductory note” Severinghaus mentions is now called “whistle” (Park and Park 2000). It was this portion of the song that was strikingly similar to the tones I had observed coming out of the shrub, both in its timbre and pitch aspects. The final, syllabic part was not present in the song I had heard.[9] Severinghaus’ description of “…the densest parts of the underbrush. Steep, heavily brush-covered slopes” as the bird’s habitat was another clue. I had given up on the idea of hearing birds when I located the sound source in the low brush, assuming they had to be frogs. But this information, together with the recording, led me back to my initial assumption that the melody must indeed have been produced by birds. The best match I now have is that I heard several Brown-Flanked Bush Warblers, a bird classified as the horornis fortipes robustipes (Clements, Schulenberg, Iliff, Roberson, Fredericks, Sullivan and Wood 2015),[10] a subspecies from the order Passeriformes, family Cettiidae (referred to in traditional Chinese writing as 小鶯 / “small warbler” and in simplified Chinese as 强脚树莺/ “strong-footed tree warbler”[11]). Years after the fact, I resumed my search to explain the presence of unusual melodic singing, perhaps inspired by the anthropophony of the subtropical mountains of South-East Asia.

Brown-Flanked Bush Warbler. Photo credit: Shen-Hui Lin    

The melodic fragment

My newly found singer has exactly the kind of timbre that was engraved in my memory. I had believed, then and there, that the tones I heard (falling within the range of one octave) were derived from the sweeping ascent of notes (across several octaves) played by the garbage truck. The striking similarity may have been just that: a pattern, coincidentally sharing the notes of a melody heard in the neighborhood. But is it possible at all that this type of Bush Warbler sang the melodic sequence that I remember having heard? I decided that using the garbage truck music was still a useful reference to answer some of my questions, partly because I believed the link was real, rather than subjective.

Severinghaus’ recording provided a “voice” similar to the one I heard and demonstrated a considerable vocal range. To determine the complete frequency range of the long whistled tones performed by the Bush Warbler, and the bird’s suitability to sing a portion of the arpeggio, I downloaded additional recordings of this species from the Macaulay Library.

I also downloaded the recording of every Taiwanese Brown-Flanked Bush Warbler uploaded to the Avian Vocalizations Center.

I did the same for the user-based collection Xeno-Canto, used by amateurs and professionals alike.

The total number of recordings of the Brown-Flanked Bush Warbler currently available on these three platforms is thirteen. Durations range from 11 seconds for a single song to over seven minutes with many songs on multiple pitches.[12] I focused exclusively on the long whistled note that starts each song and found that many of these pitches were repeated several times, during a single song bout and across different song bouts. Pitch sequences naturally produced by the Taiwanese subspecies of Brown-Flanked Bush Warbler show ascending and descending minor and major thirds, perfect fifths, and occasionally minor or major sixths, with triads being very common. One example is recording #114815 by Wayne W. Hsu, where the intervals follow the same cycle of a triad, after 4 minutes and 30 seconds:

1 .    ascending major third

2.    ascending minor third

3.    descending perfect fifth

The bird repeats this exact sequence three more times, singing four triads in a row. This overall preference for intervals used in A Maiden’s Prayer further reinforces the possibility that these birds are capable of imitating the rising arpeggios.


From all the recordings, I selected one occurrence of each pitch and lined them up in such a way that the whistle portions gradually increased in pitch. I left out pitches that had only very slight, microtonal deviations from ones I had already selected. I found three things:

1.    The complete series encompasses precisely one octave (the highest fundamental frequency being almost exactly twice the lowest one I found).

2.    Although there are microtonal deviations from the equally tempered chromatic scale, the twelve pitches approximate the tones one finds on a piano keyboard, minus one.[13]

3.   The pitch sequences naturally produced by the Taiwanese subspecies of Brown-Flanked Bush Warbler uses ascending and descending minor and major thirds, perfect fifths, and occasionally minor or major sixths.

In this recording, you can hear the twelve pitches from the whistle portions sung by different Bush Warblers. They are presented in ascending order with the sole purpose of seeking which tones occur in their natural singing patterns. I cut the syllabic parts from the recordings, since I heard only whistled sounds.

Sequence of ascending whistled portions of Brown-Flanked Bush Warbler’s songs, recorded in Taiwan   

Sonogram of the above recording (Frequency is mapped on the vertical axis and time on the horizontal)

The whistled notes of the Brown-Flanked Bush Warbler usually hover across a certain pitch range of less than a semitone, gradually moving up or down from onset till decay of the whistle. Short counter-movements may occur during this slide.[14] This is markedly different from the garbage truck music, where the frequency is rather stable from the onset until the decay of a note. The range of the bird’s whistle notes is two to three octaves above the garbage truck’s arpeggios, which extend from G4 to D6. The sustained pitches commonly sung by these Bush Warblers last for about 1.5 seconds. Again, this is very different from the high-paced garbage truck version of A Maiden’s Prayer, where each tone is around 0.33 of a second. The pace that results from sequencing the tones of a Bush Warbler coincides very well with the pace I observed in the animals’ singing, as will become clear in the following paragraph.


A reconstruction of what I heard

The pitches now available to me allowed me to correlate the tones of the garbage truck with those of the Brown-Flanked Bush Warbler and search for matches. Between different garbage truck recordings on YouTube, there are small variations in the tonal centers from locality to locality, about a semitone (G to A-flat). Interestingly, these central pitches are very near the lowest and the highest tones of the Bush Warbler recordings that I found: the above recording and sonogram cover the octave G6 to G7, approximately. Choosing a YouTube recording of the garbage truck’s music with a relatively low tonal center, around G, the main tones of the two rising arpeggios are shown below.

Sonogram of the truck’s rising melodic sequences. Nearby piano keys are given for each tone (compare with sound fragments of A Maiden’s Prayer above)    

Given the pitch range available to these birds, it indeed turns out to be possible to reproduce a fragment of the truck’s arpeggios. In the following table, the frequency ranges covered (in Hz) and the matching notes of the birds’ whistles are given.

Matching sequence #1

Using only these selected pitches from the 12 pitches found in actual recordings, and applying a slight overlapping, the reconstructed sound can be rendered as follows.

Reconstructed sequence of four tones matching a section of the first arpeggio of A Maiden’s Prayer    

Another possible match for four successive notes of one of the arpeggios that fits in the bird’s pitch range is shown in the following table and reconstructed sound recording.

Matching sequence #2

Reconstructed sequence of four tones matching a section of the second arpeggio of A Maiden’s Prayer

Summary of a possible solution and of problems


There is no certainty about the origins of the sounds I heard, since I was not able to see or record them. But there are a number of reasons why the Brown-Flanked Bush Warbler qualifies as a candidate.


1.  The microtonal instability (or the amount of “slide”) during a single whistle of this Bush Warbler is small enough to reproduce an equivalent of sustained pitches that humans use.

2.  The pitch range of the whistle portions of this subspecies’ song makes it capable – at least in theory – of reproducing the arpeggios I heard.

3.  When exhibiting its natural singing behavior, singing alone, a bird of this subspecies is capable of choosing the equivalent of intervals that humans often use; the occurrence of intervals similar to those used in arpeggiated, triadic sequences in Western art music, separated in time by many seconds, is striking.

4.  It may be possible that birds are able to recognize the same intervals in A Maiden’s Prayer.

5.  If the Brown-Flanked Bush Warblers would indeed attempt to mimic a section of A Maiden’s Prayer, then the natural duration of their whistles (averaging about 1.5 seconds) would produce the slowed-down melody as I heard it.

6.  The sharing of the melody by multiple singers may explain the short overlapping (which also happens to be a characteristic of the garbage truck tune).

There are some uncertainties and problems related to my aural identification of this bird species.


1.   Extant recordings of the the Brown-Flanked Bush Warbler were mostly from Central and West Taiwan; none were from the province of Taidong, where I heard the singing.

2.   Extant recordings were made during the morning and afternoon.

3.   Extant recordings were made earlier in the year, during the breeding season, not in late autumn/early winter.

4.   Extant recordings of its songs all include one of two types of syllabic singing after the long, introductory whistle.

5.   The Brown-Flanked Bush Warbler usually sings solitary, not collectively.


Points 1, 2 and 4 do not pose a serious drawback: the Taiwanese birdsong expert Allen Lyu confirms that the bird can be found in Taidong as well, that it does sometimes sing in the early evening (6-8 PM),[15] and that the bird may occasionally drop the second, syllabic part of the song. However, the Brown-Flanked Bush Warbler is not known for singing in groups or for singing outside the breeding season.[16]

Some clues from the science of bird song


The science of bird song should be the starting point of any further investigations, but rarely points in the direction needed. In fact, it points forcefully away from the possibilities I am looking for, that is, those that might explain multiple animals sharing parts of a tune made by humans in a coordinated manner. Without concrete evidence, my observations are of no use to a bird scientist. Problems such as the one I raise here have entered various discourses of a more interdisciplinary nature, like soundscape studies, musical composition, musicology, ecocriticism and zoology. These disciplines, and the type of sounds they study and use, move in different directions, using pathways of interpretation that may or may not be acceptable to the hard science of bird song studies. In what follows I will first consider a few relevant biological backgrounds to bird song before situating my observations within zoomusicology.


An obvious starting point for correlation with the supposed garbage truck imitation is the question of mimicking. Some of the best-known mimics are the Superb Lyrebirds from Australia, which also imitate the sounds of human technology. Halafoff writes, in 1966:

There seems to be nothing too difficult for the Lyrebird's wonderful vocal apparatus; not only can it furnish a “true copy” of any bird call, but the sounds seemingly impossible to produce within a bird's throat like the "swish" of the wings of a flock of parrots in flight, or the sound of a movie camera motor running, are given with the utmost realism. The Lyrebird's imitation is quite unlike the "rough approximation" of the human voice by tailing parrots: when at its best, it is a real reflection of the original.

Given the limited and recent exposure to “a movie camera motor running,” the Australian Lyrebird’s speed at mimicking sounds new to the species is phenomenal. It has learnt its art for ages, however, by imitating other birds. What the Lyrebird excels in is timbral manipulation of its vocal apparatus, as we can hear in this fragment of the BBC documentary The Life of Birds, presented by Sir David Attenborough.[17]

Sir David Attenborough encounters the Superb Lyrebird in Australia

The mimicking of the singing of many other birds and the sounds of a camera shutter (sometimes with motor drive), a car alarm and the chainsaws of foresters are proof of a superb ability to analyze and reproduce old and new sounds in the soundscape surrounding the Lyrebird. Although it is proof of some birds’ abilities to mimic complex and electronic sounds, there is a major difference with the imitation I believed I heard. The Lyrebirds and other birds that mimic the sounds caused by human presence, such as Parrots and Hill Mynahs, learn to mimic single sounds, sound patterns or signals. Parrots and Hill Mynahs do not even sing: their repertoire consists solely of calls and human speech (Catchpole and Slater 2003: 63). These birds also essentially mimic in solo calls, not in tandem with other birds, and not in group-wise coordinated patterns. The Lyrebird learns to mimic by itself, without a human trainer. Some parrots are individually and patiently trained by humans to do so: they do not normally learn to speak from their biological predecessors. These famous examples of mimicking tend to be based on (strings of) short sounds and display an excellent reproduction of the original timbre. The imitation of A Maiden’s Prayer I believed to have witnessed seems to be of a different order. I doubt the singers that I believe to have heard changed their timbre at all: the Brown-Flanked Bush Warbler’s normal, natural whistle-voice sounds strikingly close to what I observed. Not the timbres or durations, but the melodic material that matches the animal’s frequency range was imitated, one note at a time for one animal. There are several other mimics that excel in imitating song from other species, such as the mockingbird in the United States and the European Marsh Warbler. The latter picks up songs and calls from an average of 77 different species during its migrations between Europe and East Africa. I have not been able to find references to mimics imitating melodies of human origin, though.


Reviewing several cases of mimicry, Catchpole and Slater concluded that “The functional significance of mimicry remains something of a mystery. Miscopying seems the most likely cause in cases where it is only shown by a minority of birds within a species” (2003: 65).[18] Another way in which mistakes may enter bird song is an intermediate state of song called “subvocal learning.” This happens when young birds are not yet fully able to respond acoustically in the appropriate manners of their species. However, the very structured impression I had of the singing, according to a musical model prevalent in the area, dismisses any thoughts about the singing as a miscopying – it sounded rather like a successful copy. So are groups of birds known at all to structure their songs in a coordinated way?


Bird song scientists studied a number of different ways in which birds structure their sonic communication, some of which may apply. The most relevant song type is called “duetting,” which is found particularly in the tropics, where “duetting is most characteristic of birds of dense forest vegetation, of thick, tangled undergrowth or impenetrable scrub vegetation” (Thorpe 1972). The interlocking voices are intricately conceived and executed by duetting pairs, of mixed or same sex. Many species evolved to collaborate in “territorial duetting,” whereby they make impressive sounds together to ward off intruders (Farabaugh 1982: 106). It typically involves a male and a female pair.


In terms of pair-bonding, duets are advantageous because they may provide a means of maintaining pair and family cohesion during migration and winter flocking. Duets may also advertise the existence of a strong pair bond, thus discouraging unmated conspecifics from entering the territory in search of mates. (Ibid.: 199)


Might the Bush Warblers have suspected a common enemy and joined forces to scare it off? In a case study with Bush Warblers (Horornis Diphone) from South Korea, Shi-Ryong Park and Daesik Park used “simulated territorial intrusions” with loudspeakers to emulate an intruder.


We found that male Bush Warblers responded to playback stimuli on their territories by changing the proportion of song types given during a song bout. In our previous experiments, Bush Warblers generally approached the playback speaker within a few minutes of hearing the stimulus and then searched for intruding males. When they did not find an intruder, they started singing […]. During the experiments conducted for this paper, all subject males approached the speaker and then sang. (2000: 228-232)  

Such experiments that use modern technology to trigger responses from birds are common practice for ornithologists, also in the wild. But what these researchers play back are the signals of carefully-selected recordings of birds or predators in that same environment and not fancy musical patterns that have not been part of the species’ long-term soundscape. Loudspeakers are always put up in the center of their territory. It is therefore unthinkable that the sound of the garbage truck played the role of invisible intruder, like the loudspeaker in the case of the Korean Bush Warbler, since birds in general possess an exceptional ability to localize sound sources through hearing. They would readily be able to establish that the sound source was much too far away to pose a threat.


At times birds have been known to produce “music-like” phrases similar to the one I heard, with exact questions and answers exchanged over and over again. Writing about duetting and antiphonal singing of just one family of species (Meliphagidae), William Homan Thorpe (1972: 7) distinguishes different levels of response:


The series proceeds from a simple answering of partners or a duetting in flight display – not at all well co-ordinated – through a mixed antiphonal duet of independent calls to a highly synchronised unison song, and finally to antiphonal song of the highest precision. It seems also that unison song may spread over into group singing where several pairs take part.


Complex song and group singing are possible, then, when the melodies arise from the birds themselves. My observation, when I finally had a chance to closely listen to my birds, was that there were more than two birds involved, like a “double duet,” which has been found in other species as well. It may take the form of coordinated singing of more than two birds in a “duet train,” as a male-female-male call, for example (Logue and Krupp 2016).


If the musical resemblance between the garbage truck’s A Maiden’s Prayer and the animals singing has not sprouted primarily or wholly from my imagination, then what could it be? Could the singing be a sign of a different kind of intelligent, perhaps even “musical” response to the sonic environment, and not just to its own or other species? Could it be done for aesthetic reasons? That is the kind of response that bird scientists, up to now, firmly deny to be possible. It cannot be proven that birds are “musical,” because “music” is a typically human idea. In scientific terms, bird song is meant to communicate signals; it is not done for pleasure or beauty. The primary functions of bird song are sexual selection (attracting female mates, selecting male mates) and defense of territory (Catchpole and Slater 2003: 187-189). The broader question as to why birds sing is in “some ways the most difficult question” (ibid: 67-69).

Investigations from the humanities


While biologists emphatically move away from “romantic” interpretations of bird song as something akin to human music, scholars, philosophers and artists from different backgrounds are trying out a host of different approaches to understand bird song and bird signal from other perspectives. Some of these disciplines co-exist peacefully with the science of avian song, others question some of science’s premises. The least offensive to scientists are artists and composers who use bird song as inspiration to create new works by integrating it in their pieces. They hear “music” in bird song, but make no claims about the science of it. Well-known examples are Cantus Arcticus, concerto for birds and orchestra (1972) by Finnish composer Einojuhani Rautavaara and the works of French composer Olivier Messiaen, who based his pianocycle Catalogue d’Oiseaux (1958) and many other compositions on his notations of bird song.[19] New Zealand composer Jack Body let actual birds play out his musical phantasies, based on an ancient Chinese practice that could be considered a traditional form of interspecies music making. He got his idea while making a documentary film about music in China in 1989. He chanced upon residents using different contraptions that causes groups of pigeons to produce a continuous whistling sound when flying. After learning how they made these small whistles, Body proposed to use many different ones on one flock of birds, resulting not in a single-pitched whistling sound, but a range of frequencies. The result, which can be heard and seen in the film ‘Big Nose’ and Body Music,[20] is described by Body as “a mystical kind of sound, because it has no beginning or end. […] The result is so full and rich and ethereal” (McGuire and Watson 1988).


No bird song scientist would take offence from such projects, nor from most other ideas developed by composers and artists wishing to cross the boundaries of human and avian music. And some of them actually come to the aid of bird song science, with their acute hearing. Magnus Robb, born in Scotland, discovered his calling as bird song scholar through his work as a composer. Trained in composition, he began to use the songs of birds as the raw material for his compositions, like the Siberian Rubythroat (Luscinia calliope) for his piece Summoning Dawn. Robb applied bird song in a Messiaenian vein, but also used newer technology (not just aural transcription) and looked for more exactness and detail in how bird song is produced. As he immersed himself deeper into the music and scientific studies of birds and other species in the animal kingdom, he realised that variations in bird song might contain clues about distinct species which were overlooked as such. His intimations proved to be successful. Initiated into bird song as a composer, he ended up within the hard side of science, publishing about his discoveries of new (sub)species of birds based in part on their distinct calls and songs (Robb and the Sound Approach 2015).

Perspectives from zoomusicology


Around 1990 I bought an LP album entitled The Unknown Music of Birds (Szöke 1987). The record summarizes decades of bird song study by the Hungarian ornithologist Peter Szöke, who is credited for coining a term for the predecessor of the new field of zoomusicology when he named his own field of research “ornithomusicology” in 1963.[21] A key method employed by Szöke is to slow down bird songs, so that its complex structures can be more readily appreciated by the human ear. Though other ornithologists as well as composers have employed this technique, Szöke has driven it further and associated his results emphatically with human musical forms. On the sleeve notes, he systematically lists various musical procedures that we can find in man-made music. It reads and sounds somewhat like the evolution of the abstract forms of musical sound, from simpler to more complex. Amongst others, the following examples are given,[22] whereby Szöke presents natural versions of bird song fragments and ones stretched up to 64 times the original duration:


Side A

    • Band 3 A). Sounds having unchanging, steady pitch are “musical tones” (Harris’ Sparrow, Himalayan Cuckoo, Hoopoe)
    • Band 3 B). Sounds having continuously changing, gliding or other irregular pitch are “non-musical tones” (Kea Parrot, Nuthatch, Black-headed Gull)
    • Band 4. The simple pitch intervals of our human music in bird voices (Whooper Swan, Asiatic White Crane, Domestic Fowl, Great Tit)

 Side B

    • Band 1. Human-like biological rhythmicity in bird vocalizations, calling in 2/4 bars (Great White Heron), in 3/4 bars (Rock Partridge), 5/4 bars (Little Wattlebird), regular alternation of 4/4 and 5/4 bars (Grasshopper Sparrow)
    • Band 2. Long-buzzing, rhythmized singing forms (Grasshopper Warbler, Savi’s Warbler, River Warbler)
    • Band 3. Birds too are capable of transposing their musical motifs into lower or higher registers, which was hitherto known only in the music of man (Orange-breasted Bush Shrike, Wood Lark, Red breasted Flycatcher, Great Tit)
    • Band 5. Human-like strophic song (lied) forms of several melodic lines (Wood Lark, Veery, Gray Warbler)[23]
    • Band 6. Developed avian singing forms of non-musical tonal structure (our “contemporary music” in birds) (Wren, Icterine Warbler, Richmond Cardinal, Blackcap)
    • Band 7. The highest and most human-like peak of the musical sound evolution in birds (Hermit Thrush)

“The Icterine Warbler” from Szöke’s LP, in natural and slowed down speed

For the next-to-last track, the apotheosis, presented as a proof-of-sorts, I quote the sleeve note in full:


  • Band 8. Conjuring of a folksong-like bird melody out of its natural hidden form and then back to the same microacoustical hiding place: Hylocichla guttata (Hermit Thrush), at first the melody is indistinguishable, however it is slowed down step by step, and then the slow bird melody is sung by the author (in a nasal voice). This human version is then gradually speeded up until it reaches the high register and the short duration of the original (natural) bird song, and the melodic shape is lost to our ears. Immediately after it we hear the original song produced by the bird again enabling us to make a comparison between them. (Szöke 1987: sleevenotes)

Record cover of Peter Szöke’s The Unknown Music of Birds


The final track takes a Hermit Thrush song and lets the same opera singer we heard before make an adaptation of it (“beautify” it, in Szöke’s words).

The record was clearly compiled to show that human hearing has many limitations in appreciating bird song at its natural speeds. It seems to say that it is absolutely necessary to alter the music (by slowing it down) in order to be able to derive anything meaningful from the sound patterns themselves. This simple, yet effective technical process helped get Szöke’s message across that birds’ music can be understood in terms of human music.


I have played this record over and over again in the early 1990s and used it in theatrical performances. Some bird songs are slown down an octave at a time (at half, quarter, one-eighth, one-sixteenth or slower speeds), drawing the listener gradually further into the finer details of the sonic elements of bird calls. Others are played at natural speed and then immediately several octaves slower. At low speeds, some songs turn into a booming melodic pulse, evoking the sounds of a ship’s horn or electronic music. One realizes that our hearing is not equipped to perceive the many fine nuances that birds put into their song. Most of it is lost to our ears.


But what Szöke is showing here is not that the sounds of passerines and humans are made for similar purposes. He remains a bird scientist when he writes:

[We] are able to unambiguously establish that avian music is an independent sub- and pre-human biological sphere of the phenomenon of "music" in the widest (not merely human and artistic) sense of the concept of the word. Bird music exists outside the sphere of arts and is independent of the music of man. Nevertheless, having common philogenetic roots with it, birds have developed musical forms identical with those of human music (first of all of vocal folk music). The evolutionary history of the birds' biological musicality preceded the origins of human music by many millions of years.

Nowadays, and in fact before Szöke’s 1987 record as well, some ornithologists would disagree with the emphasis on the word “music” and all the musical ideas associated with Szöke’s verbal presentation. Szöke remains close enough to ornithology and distant enough from aesthetics to be taken seriously by bird scientists, but his forays into the music-analytical approach did perhaps reduce his impact in ornithological circles.[24] Much of the scientific literature about bird song avoids the term “music” altogether and prefers to talk about communication, signals, vocalizations, phrases, duetting, etcetera.

The French composer and ornithologist François-Bernard Mâche went one step further than Szöke when he conceded, in his book Music, Myth and Nature, that “there is not a single musical procedure which does not have its equivalent or its prototype in one or the other of the innumerable signals of animals.”[25] Mâche is credited to be the founder, in the 1980s, of a branch of music research focused on the animal kingdom, coined zoomusicology. Mâche’s research agenda takes Szöke’s ornithomusicology (coined in 1963) to a broader level of investigation. What Szöke merely implied – at least with his bird record – is made more general and also more explicit by Mâche. General, because it does not just apply to the species for which we, humans, have developed such musical ears; explicit, too, because Mâche wishes to explore the possibility, however tentative at the moment, that addressing musical aspects of animal behavior might reveal an underlying aesthetic sense, a common root of communication through sound that may be widespread across many species. Szöke steered clear of such implications within his research in the quote above, where he asserts that bird music “exists outside the sphere of arts and is independent of the music of man.” Mâche opens the door to a bolder question, where deep interrelationships of human and animal sound making may be suspected. In his 1983 book he wondered,


if it turns out that music is a wide spread phenomenon in several living species apart from man, this will very much call into question the definition of music, and more widely that of man and his culture, as well as the idea we have of the animal itself.[26]

His leads have been followed up after the turn of the millennium with new investigations and a further theoretical underpinning of the discipline that Mâche named. Drawing upon zoosemiotics, ethology, musicology, Mâche’s work and other influences, and sensitive to the implications which the word “music” carries, Dario Martinelli defines zoomusicology as the “aesthetic use of sound communication among animals.” He further writes: “The idea behind this definition is in its several implications. Firstly, one avoids the use of the dangerous word, ‘music’, a concept that must be handled with extreme care, even when related to just human activity, but does not avoid another dangerous word, ‘aesthetic’.” (Martinelli 2008) He further places zoomusicology squarely within the humanities, as a “musicology of animals,” and not within one of the natural sciences and puts more emphasis on the new discipline’s own “analytical tools and theoretical reflections” than on presenting new hard-wired data (Ibid.). Obviously, zoomusicology speaks, at least in veiled terms, of a promise: some day it may show its empirical value when the tools have become sharp enough to cut through the most difficult questions it raises, and it will lay bare new horizons of cross-species musical understanding. If that happens, then Mâche’s bigger questions about the definitions of music, man, culture and animal may receive more than a new twist. It is interesting to note that Martinelli bets on the more general idea of finding an aesthetic root in animal sounds and not on the term that currently carries controversial overtones: “music.”


One of the most vocal individuals who have joined Martinelli’s cause in the last decade, based upon a steadily growing body of work at the cutting edge of music, animals and nature, is philosopher and musician David Rothenberg. A trilogy of books (on bird, whale and insect sounds) explores questions about the supposed musicality of animals and has stirred debates among scientists, philosophers and musicians. Unlike most players in the field of animal music/sound studies, Rothenberg wears all three hats (as a philosopher, artist and most recently as scientist) at different times, if not simultaneously. Beginning with more or less parallel or overlapping careers as a jazz clarinetist, and philosophy professor, he continued to combine these two efforts by exploring the science and philosophy of bird song in writing, while exploring the art of it by playing his instrument together with birds. The resulting book-CD Why Birds Sing, with its daring supposition that humans and birds share an interest in making music for the sheer beauty of it, led to a documentary of the same name, broadcast by the BBC (Davidson and Ramsden 2007).

The film follows Rothenberg while travelling around the world to forests, aviaries and for musical collaborations, and it portrays other musicians, a poet, bird imitators, and bird song scientists. Rothenberg’s fundamental critique is that scientists do not accept that birds may also sing for pleasure. He does not deny the fact that birds sing to attract mates and to repel rivals, but wants to understand better why bird song can be so complex and versatile. There is plenty of support for Rothenberg’s idea that birds sing beautifully, and it is pointed out that poets and others took bird song seriously long before scientists did so. Some scientists leave the door open to an aesthetic interpretation, and all of them have an obvious interest in bird song and derive pleasure from studying it and listening to it. But two of the heavyweights of bird song studies, Donald Kroodsma and Peter Slater, clearly argue against the musical viewpoint. Slater asserts, for example:


I am not sure that I would want to use the word ‘music’ in relation to bird song, because human music is qualitatively different from bird song. I don’t think birds use scales in the same sense as we do, or anything like that. You don’t want to mix up two things that are very distinct from one another. (Ibid.)


But why then do many humans take a deep interest in bird song, why are composers and others learning to imitate these songs quite precisely, including their scales? And why did Peter Szöke find so many shared sound structures in human and bird song? Isn’t Slater’s antidote to Rothenberg’s anthropomorphism in itself an ornithomorphism? It is clear that our songs share more features than Slater suggests. Donald Kroodsma likewise seems to draw up a wall around his singing birds, when he says,


I am not sure anybody knows what music is. I suppose as a scientist I might say, it is any series, any pattern of sounds that strikes us as somewhat pleasing. But not all human music is pleasing to me, so I don’t know what human music is. I don’t really know what birdmusic is, or whether bird song is music. (Ibid.)


Surely Kroodsma has had “responses” to music, as an anthropos, and he would be able to say more about music than this. He may not be able to rid himself of his own human subjectivity as it comes to music, but is that reason enough to decline the possibility of birds having some sense of the aesthetic, or at least other than purely functional reasons, as Rothenberg wants to know?

At the same time, the scientists make many valid points. They have spent many decades on repetitive, number-driven analysis of bird song to prove many small points, one at a time. Kroodsma analyzed thousands of songs, of one bird even, to reach conclusive answers. In response to Rothenberg’s efforts at duetting with birds, where he imitates parts of their song with his clarinet and looks out for birds imitating phrases of his, Kroodsma and Slater both remark that it is easy to trigger a bird’s response to human sound ­–  Kroodsma dryly suggests the sound of a vacuum cleaner would do so. They are not impressed with Rothenberg’s intuitive methods, backed with sonograms to point out those places where Rothenberg felt a bird was answering him. At the end of the film the two scientists and their colleague Kate Buchanan reluctantly meet Rothenberg, at the sidelines of a Berlin conference, but the wall between them stands as tall as ever. If Rothenberg cannot produce enough “interesting numbers” to prove his point, he should not try to tell scientists why he thinks bird sing. Rothenberg then returns to his music projects, before addressing the science again.

Rothenberg is still pursuing his tireless, as well as restless, quest for answers in his works with mammals and insects (Rothenberg 2008; Rothenberg 2013) and most notably in his book Survival of the Beautiful: Art, Science and Evolution, where he writes, “I do not believe evolution as we know it can explain art, but a deeper consideration of art can enhance our understanding of evolution” (Rothenberg 2011: 20).


In the end, the birds I witnessed are not like Rothenberg’s duets with birds, mammals or insects, or like any other of the examples I discussed above. It seems to me that the interspecies communication I observed, not willed by any human being, but supposedly willed by a group of birds, is different from all the cases I described above. If the birds would not have repeated something so strikingly close to the garbage truck music, over and over again, I might not have noticed something special about their singing. If my Bush Warblers were indeed singing the garbage trucks’ music, does it make them more musical? Is it proof of a sense of the aesthetic? Is it just another one of many fantastic mistakes of evolution? Will it have any consequences for birds or our understanding of bird song?

A mutual affair?


It is a giant step from well-known examples of birds mimicking sounds of (or caused by) humans to animals producing a collective, shared response based quite precisely on human musical patterns. But is it impossible? I give the last word to the birds, but indirectly, through the voices of two Taiwanese ornithologists of the Wild Bird Society of Taipei. When I approached them with my questions, their first response was a spontaneous imitation of the Brown-Flanked Bush Warbler’s song. They made a wordplay around the long whistled introduction and the shorter and longer syllabic parts that normally finish this bird’s song. They explained to me that no other bird is verbally imitated in this way: only when imitating the song of the Brown-Flanked Bush Warbler do Taiwanese ornithologists use a human language, “paraphrasing” what the birds might say. Having failed to obtain concrete evidence of my observations, the imagined conversation between the birds could not be more appropriate for illustrating my case.

Taipei ornithologists imitate the two types of the Bush Warblers’ song

“Niiiii hui qu!”

“Wooooo bu hui qu!”


“You----- (have to) go back”

“I----- don't (want to) go back!”


Is our human interest in learning this species’ vocal-musical grammar really a mutual affair?



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