T h e Master Singer

From the tropical rainforest to the urban jungle, birds have conquered many habitats on our planet – and they sing in nearly all of them. Henrik Brumm at the Max Planck Institute for Ornithology in Seewiesen studies how they use song to communicate with each other. He has taken a particular liking to one extraordinarily talented singer.

TEXT CLAUDIA STEINERT

henever his cat lays a Only those whose vocal apparatus – the dead bird in front of his syrinx mentioned above – comprises door, Henrik Brumm particularly complex structures fall into vacillates between sym- this category. pathy and scientific cu- For his doctoral thesis, Henrik riosity.W His inquiring mind usually wins Brumm studied how the urban noise out, and Brumm studies the bird’s vo- in Berlin affects the communication of cal organ, called the syrinx. At least nightingales – how the birds get their this way the animal still makes a con- message across over the sounds of cars tribution to science. After all, Henrik honking, sirens wailing and airplanes Brumm is a behavioral biologist. He roaring around them. Germany’s cap- wants to know how animals commu- ital was ideal for his project: no other nicate with each other – how they major German city has such a large court each other, for instance, or how nightingale population. They prefer to they tell each other about the best build their nests on the ground amid feeding areas, and how they defend herbaceous hedges that sprawl over their territory. That’s why, since com- lawn edges and curbs, and that are not pleting his doctoral thesis, Brumm has always trimmed as frequently as in been researching what is likely the other cities. most complex form of communication in the animal kingdom: birdsong. ON THE PROWL AT DAWN Of the more than 10,000 known bird species, around 4,000 are song- Brumm’s decision to carry out the night- birds. While every bird can produce ingale project wasn’t entirely without sounds, not all of them can sing. The ulterior motive: it suited his biorhythm. cuckoo, for example, can manage little Unlike most songbirds, the nightingale more than his eponymous call. Parrots sings not only at sunrise, but also at imitate sounds and even human speech, night. Brumm envisioned himself tak-

but that doesn’t make them songbirds. ing off before or after hitting a few Photo: Axel Griesch Master Singer Master e h T

Photo: Axel Griesch

Photo: Axel Griesch BIOLOGY &MEDICINE_Ornithology page shows a common chaffinch. common a shows page this on Starnberg.image near The forest a in birdsongrecords Brumm Henrik 3 | MaxPlanckResearch 16MaxPlanckResearch 49 BIOLOGY & MEDICINE_Ornithology

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Left King of the singers: Most of the 80 species in the wren family use loud and complex songs, but no other bird can match the musician wren – his melodic singing is unique in the animal kingdom. Right The song of the musician wren has striking similarities to human compositions: song frequency over time (1), transcription of the notes of the song (2), opening melody of the second movement of Haydn’s Symphony No. 103 (3), and the opening of Bach’s Fugue No. 20 in A minor, BWV 889 (4). pubs, equipped with a night vision de- to make themselves heard in the city. the hope that it will improve business. vice, laser rangefinder and sound level “Nightingales sing more loudly during When the Uirapuru sings, so the sto- meter. But that didn’t pan out. “I real- the week than on the weekend, because ries go, all other animals in the forest ly got cheated on that one,” he says the streets are louder on weekdays,” ex- fall silent and gather around it to lis- with a wink. plains Brumm. ten to its songs. The university had to cut costs. Birdsong is so characteristic that or- Yet the song of the Uirapuru serves Rather than a night vision device and nithologists can recognize a species by a very practical purpose: like all song- laser rangefinder, his supervisor gave it. But that takes practice – except in the birds, it uses its melodies to attract fe- him binoculars and a tape measure. case of one of their representatives: male birds during mating season. The Working in the dark was thus impossi- “Even amateurs can identify the musi- female birds can tell from the song how ble. From then on, he dragged himself cian wren,” says Brumm. This bird, viable a male bird is, and consider it a out of bed at 3:30 each morning and which lives in the Amazon and mea- sign that the singer evidently managed got on his bicycle. He pedaled to the sures just 12 centimeters, is smaller to conquer a food-rich territory – how city highway, roamed through parks than a sparrow and has similarly incon- else would he have so much time for and stood for hours at highly frequent- spicuous coloring. But while it’s not singing! In the Amazon, communica- ed intersections. As soon as he saw a much to look at, when it opens its beak tion by song is also important for an- nightingale, he held up his sound lev- and begins to sing, it sounds as if mu- other reason. In the undergrowth of the el meter and recording device. sic were floating through the jungle. tropical rainforest, with visibility often After recording the song, he rolled below three meters, it is very difficult out his tape measure and measured the A VIRTUOSO IN THE RAINFOREST for animals to see their potential part- distance between himself and the bird. ners. Calls and songs, however, pene- From the distance and the sound level, The musician wren has gained quite trate the dense vegetation. he then calculated the absolute volume some renown in its native habitat. Due In 2003, Brumm himself stood in of the song. His conclusion: the more to its remarkable song, it is as signifi- the jungle of the Amazon rainforest for noise surrounding the nightingales, the cant in the culture of indigenous peo- the first time. Around him, everything louder they sing. They display what is ples as the nightingale is in ours. The was green, with trees and bushes block- known as the Lombard effect. locals revere the small bird, which ing his view. Suddenly he heard this Lombard was a French physician they call “Uirapuru,” and numerous song and he immediately knew: it’s him who noticed, some 100 years ago, that legends have been woven around it. – the musical bird that he had previous- we involuntarily adjust our volume ac- Anyone who hears it sing will enjoy ly known only from audio recordings. cording to the noise level of the envi- good fortune in hunting, in love, or Henrik Brumm wanted to know why ronment, so that those we are talking even in all aspects of life. Some restau- the musician wren sings like that. Why to can better understand us. And it is rateurs or shop owners even bury a do its songs sound to humans like a

precisely this trick that birds, too, use dead Uirapuru in front of their door in concert musician’s performance, while Photo: Michel Clément; graphic: MPI for Ornithology

50 MaxPlanckResearch 3 | 16 Photo: Michel Clément; graphic: MPI for Ornithology

Photo: Axel Griesch ferred totravelthroughtheAmazon some invoke as the primeval music that some invokeastheprimeval musicthat perhaps evencarrieswithin itwhat didn’t wanttoknowwhetherthebird er themusicianwrenismusical. Healso Brumm’s aim wasn’t to discover wheth Brumm. Butthatwasn’t hisconcern. perception ortonality,” ofintervals says don’t knowwhetherthebirdhasany tween successivenotes.“Ofcoursewe –thespansbe- to bethenoteintervals ration, onlyonefactorremained.Ithad either thenotesthemselvesortheirdu- music agreed,”saysBrumm. “Even thosewhoknewnothingabout original melodywastheclearwinner. two variantssoundsmoremusical.The They were asked to decide which of the people withnomusicalinclinations. cert pianists,garagebandfounders,and bled version for study participants: con- played boththeoriginalandjum- tion ofthenotes–onlyorder. They They didn’t changethe pitch ordura- up theindividualnotesofeachsong. dies were birdsong. Next, they jumbled ment werenottoknowthatthemelo- synthesizer, aslistenersintheexperi many differentmusicianwrensusinga searchers’ fingertips. sounds fromaroundtheworldatre This putanincrediblevarietyofbird can uploadrecordingsofbirdsongs. one –scientistsandamateursalike the xeno-cantodatabase,whereany- that. SoBrummandDoolittleused no one would have paid him to do himself and collect bird sounds,but and figures,notsubjectiveopinions. to be quantifiable. They wanted facts sound likemusic?Thefindingsneeded does thesongofmusicianwren that hadlongoccupiedBrumm:why an experimenttoanswerthequestions did. Together, the two began to develop understood moreaboutmusicthanhe Brumm waslooking for someonewho ologists whoresearch animalsounds. Doolittle. Doolittlewaslookingforbi- Scotland, hemetmusicologistEmily to playtherecorder?Nooneknew. other birdssoundlikechildrenleaning First theyreproducedthesongsof Of courseBrummwouldhavepre Since theresearchers hadnotaltered At the University of St Andrews in - - - -

software to fathom every last detail. last every fathom to software latest the using – computer the on subjects study feathered his of songs the analyzes Brumm Henrik

Musculature and left sides in rapid succession. rapid in sides left and right the between alternate or time, same the at notes different two sing therefore can Songbirds another. one of independently function syrinx the of sides two the muscles, the control brain bird the in neurons different Since song. the of pitch the regulate factors, additional with conjunction 52 tympaniform membrane and in this way, in way, this in and membrane tympaniform medial the and labia, lateral and medial the as known labia, the of position and tension the adjust muscles These muscles of set separate a by controlled is which of each bronchus, each in source sound separate a houses that syrinx two-part a have Songbirds bronchi. primary the into branches it where trachea the of base the at located is which syrinx, the called organ unique a using vocalize birds larynx, their with Below Lateral Lateral labium MaxPlanckResearch 3 MaxPlanckResearch Unlike mammals, producesoundswho

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as theother–weperceive theinterval stance, onefrequencyistwice ashigh in asimplemathematicalratio –forin- When thefrequencies of two notes are they vibrate,thehigher frequency. brate atacertainfrequency: thefaster note,soundwavesvi- waves. Forevery ing brainsandthephysicsofsound has somethingtodowithourorder-lov a constructofWestern culture.Italso as harmonicandbeautifulisn’t merely Our perception ofperfectconsonances EVOLUTION ASACOMPOSER and createdisharmony. which occurfrequentlyinjazzmusic wren, andtheyavoiddissonances, much rarerinthesongofmusician songs. Imperfectconsonancesare also usedinmanyfolkandchildren’s sound particularlyharmonic;theyare tonal steps.To ourears,theseintervals offour,call aninterval fiveoreight or octaves–that’s whatmusictheorists sonances. Hewarblesinfourths,fifths ten in whatare known as perfectcon- wren does,infact,singparticularlyof- closely, it turned out that the musician so pleasingandbeautiful. why thesongofthislittlebirdsounds made music. He only wanted to know is supposedtohaveinspiredallman Upon analyzing the melodies more - - - as calmandharmonic.Anoctavehas ered thatbirdsandhumans, despite duet withthemselves. two notessimultaneouslyand singa bronchi. Thisallowsbirdsto produce where itbranchesintothe primary is locatedatthebaseoftrachea butratherthesyrinx,which the larynx, duce sound,however, birdsdon’t use what theadultssingtothem.To pro- mans learnspeaking:thechicksimitate right unmusically. our ears,manybirdspeciessingdown- found topreferperfectconsonances.To To date,nootherspecieshasbeen cian wrensandnotinanyotherbirds. nances developedspecificallyinmusi- clear iswhythispreferenceforconso- one thatprecededit.Whatremainsun be somewhatmoremusicalthanthe dominant. Eachgenerationwouldthen sing them,thistraitwouldbecome more frequentlywithmalebirdswho if theypreferharmonicsongsandmate could be the driving force behind this: advantage. The female birds lutionary of songprobablygivesthebirdsanevo- says Brumm. Thistype nant intervals,” one birdspeciesspecializedinconso a fourth3:4. the frequency ratio 2:1, a fifth, 2:3, and Brumm andhiscolleagues discov Songbirds learnsingingthewayhu “The intriguingquestioniswhythis - - - -

Photo: Axel Griesch; graphic: Sue Anne Zollinger/MPI for Ornithology Photo: Axel Griesch; graphic: Sue Anne Zollinger/MPI for Ornithology

Photo: MPI for Ornithology conditions as above. as conditions same the under song the of spectrum Frequency right Bottom as they do in a quiet one (left). (left). one quiet a in do they as noise. Brummisnowinvestigating diovascular diseasescausedby constant European Uniondie each year from car estimates that200,000people inthe dome. TheWorld Health Organization metropolis likeacheese gulfs every communicate, duetothenoisethaten- becoming moredifficultforbirdsto have provensuccessful.” mechanism. “Theprincipleseemsto sparrow totheostrich–possessthis also showedthatallbirds–fromthe discover thisprincipleinbirds,they only didBrummandhiscolleagues to speakandsing,respectively. Not for childrenandchickstolearnhow same principle. It is thus much easier tone. Thesyrinxofbirdsworksonthe positions thatallproducethesame like awave,therearemultiplecorrect close, butintheprocessalsoundulate tic vocalcordsdon’t just openand accurately. However, becausetheelas- be incrediblydifficulttoimitatesounds cord position for each sound, it would nation produceswhichsound. longtimetolearnwhichcombi- a very learning to speakmustexperiment for tain tone.Childrenwhoarejust sion inthevocalcordsproducesacer- nation ofairpressureandmuscleten- vocal cordsopenandclose.Thecombi errors. Whenhumansspeak,theelastic system thatisparticularlyforgivingof mechanism to produce sound. It is a their different anatomies, use thesame page Left listen to it several hundred times a day. day. a times hundred several it to listen they species: own their of birds male of song the of enough get can’t just birds Female button. a pressing by themselves songs play can animals The to. listening enjoy most birds female Top right Top In bigcities,however, itisrapidly If therewerejustonecorrectvocal Birds sing twice as loud (right) in a noisy environment environment noisy a in (right) loud as twice sing Birds In the soundproof lab, the researcher tests what what tests researcher the lab, soundproof the In

- - Berlin’s Tegel Airport. He originally been studyingbirdpopulationsat wanted totesthowtheybehavewhen processes inhumans.” model for better understanding these tem functioning. “The birds could be a age faster or disrupts their immune sys- ic stressinthem,causestheircellsto bances inbirds,too,ortriggerschron- whether noiseleadstosleepdistur

l l l TOPOINT THE room may gradually grow louder and louder. louder. and louder grow the gradually in may volume room the room, small a in speaking are people several example, more for If, speak loudly. involuntarily people increases, level noise surrounding the If environment. their of volume the to voice their adjust to animals) some also (and people causes effect: Lombard song. its in consonances favors perfect wren musician the Only songs. simpler much have wren) song the and wren chestnut-breasted (the wren musician the of relatives nearest The musicality. bird’s the distinctive to points name English the even and folklore, and South in mythology role American prominent a plays species the song, unusual its to Due range. large a has Musician wren: Musician GLOSSARY For sometimenow, Brummhas

Lombard effect. Lombard a they so communicate, to birds for difficult more it make environments Loud m of cords vocal the way: same the in sounds produce humans and Birds b the because music like sounds wren musician the of song the To ears, human of overlapping waves. overlapping of theme. or tonality consonance, of concept any have they whether or octaves. It is not known how the birds themselves perceive their song or dapt their song and likewise sing louder – a phenomenon referred to as the the as to referred –aphenomenon louder sing likewise and song their dapt ird sings in perfect consonances. The melody is made up of fourths, fifths fifths fourths, of up made is melody The consonances. perfect in sings ird ammals and the labia of the syrinx in birds oscillate in the same patterns patterns same the in oscillate birds in syrinx the of labia the and ammals A member of the wren family, this bird lives in the Amazon, where it This phenomenon, named after French physician Étienne Lombard, Lombard, Étienne physician French after named phenomenon, This - the terminalseventuallycloseand in Seewiesen. the birdsatMaxPlanckInstitute Brumm playsMunich’s trafficnoiseto couple ofyears.Inthemeantime, ies therewillhavetowaitanother port thwartedthat.”Sothefieldstud yet: “TheoperatorsofBerlin’s newair capital city, butthathasn’t happened ing sitesinthenorthernpartof peace andquietdescendsonthenest BIOLOGY &MEDICINE_Ornithology 3

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Frequency Sound pressure (kHz) (mPa)

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