The songbird syrinx morphome: A three-dimensional, high-resolution, interactive morphological map of the zebra finch vocal organ

BMC Biology

Volumn 11, Issue , 2013, Pages

  Düring, Daniel N ^a   Ziegler, Alexander ^b   Thompson, Christopher K ^a,c   Ziegler, Andreas ^d   Faber, Cornelius ^e   Müller, Johannes ^f   Scharff, Constance ^a   Elemans, Coen P H ^g  

^a FREIE UNIVERSITÄT BERLIN   (Germany)

^b HARVARD UNIVERSITY   (United States)

^c SCRIPPS RESEARCH INSTITUTE   (United States)

^d CHARITÉ UNIVERSITÄTSMEDIZIN BERLIN   (Germany)

^e UNIVERSITY HOSPITAL MÜNSTER   (Germany)

^f HUMBOLDT UNIVERSITY   (Germany)

^g UNIVERSITY OF SOUTHERN DENMARK   (Denmark)

Author keywords

[No Author keywords available]

Indexed keywords

ANIMALIA; PASSERI; TAENIOPYGIA GUTTATA;

ANIMAL; ANIMAL COMMUNICATION; ARTICLE; HISTOLOGY; PHYSIOLOGY; SONGBIRD;

ANIMAL COMMUNICATION; ANIMALS; SONGBIRDS;

MLCS; MLOWN;

EID: 84871945961     PISSN: None     EISSN: 17417007     Source Type: Journal    
DOI: 10.1186/1741-7007-11-1     Document Type: Article

References (130)

1. Hauser MD, Chomsky N, Fitch WT. The faculty of language: what is it, who has it, and how did it evolve?. Science 2002, 298:1569-1579. 10.1126/science.298.5598.1569, 12446899.
2. Doupe AJ, Kuhl PK. Birdsong and human speech: common themes and mechanisms. Ann Rev NeuroSci 1999, 22:567-631. 10.1146/annurev.neuro.22.1.567, 10202549.
3. Woodgate JL, Mariette MM, Bennett ATD, Griffith SC, Buchanan KL. Male song structure predicts reproductive success in a wild zebra finch population. Anim Behav 2012, 83:773-781.
4. Collins S. Vocal fighting and flirting: the functions of birdsong. Nature's Music: The Science of Birdsong 2004, 39-79. San Diego, CA: Elsevier, Marler PR, Slabbekoorn H.
5. Sakata JT, Vehrencamp SL. Integrating perspectives on vocal performance and consistency. J Exp Biol 2012, 215:201-209. 10.1242/jeb.056911, 22189763.
6. Irwin DE, Bensch S, Price TD. Speciation in a ring. Nature 2001, 409:333-337. 10.1038/35053059, 11201740.
7. Edwards SV, Kingan SB, Calkins JD, Balakrishnan CN, Jennings WB, Swanson WJ, Sorenson MD. Speciation in birds: genes, geography, and sexual selection. Proc Natl Acad Sci USA 2005, 102:6550-6557. 10.1073/pnas.0501846102, 1131863, 15851678.
8. Fee MS, Scharff C. The songbird as a model for the generation and learning of complex sequential behaviors. ILAR J 2010, 51:362-377.
9. Mooney R. Neurobiology of song learning. Curr Opin Neurobiol 2009, 19:654-660. 10.1016/j.conb.2009.10.004, 19892546.
10. Bolhuis JJ, Okanoya K, Scharff C. Twitter evolution: converging mechanisms in birdsong and human speech. Nat Rev Neurosci 2010, 11:747-759.
11. Wild JM. Neural pathways for the control of birdsong production. J Neurobiol 1997, 33:653-670. 10.1002/(SICI)1097-4695(19971105)33:5<653::AID-NEU11>3.0.CO;2-A, 9369465.
12. Heimovics SA, Cornil CA, Ball GF, Riters LV. D1-like dopamine receptor density in nuclei involved in social behavior correlates with song in a context-dependent fashion in male European starlings. Neuroscience 2009, 159:962-973. 10.1016/j.neuroscience.2009.01.042, 2667808, 19356680.
13. Poirier C, Vellema M, Verhoye M, van Meir V, Wild JM, Balthazart J, van der Linden A. A three-dimensional MRI atlas of the zebra finch brain in stereotaxic coordinates. NeuroImage 2008, 41:1-6. 10.1016/j.neuroimage.2008.01.069, 18358743.
14. Schmidt MF. Neural control of birdsong. Encyclopedia of Life Sciences 2009, Chichester, UK: John Wiley & Sons, Ltd.
15. DuVerney M. Diverses observations anatomiques, II. Historie de l'Adademie Royale 1686-1699 Paris 1686, 2:6-7.
16. King AS. Functional anatomy of the syrinx. Form and Function in Birds 1989, 4:105-192. New York: Academic Press, King AS, McLelland J.
17. Huxley TH. A Manual of the Anatomy of Vertebrated Animals 1871, New York: D. Appleton and Co.
18. Setterwall CG. Syrinx hos polymyoda passeres. 1901, 1-105. Gleerupska Universitetsbokhandeln; PhD thesis; Lund, Sweden.
19. Ames P. The morphology of the syrinx in passerine birds. Bull Peabody Mus Nat Hist 1971, 37:1-194.
20. Gaunt AS. An hypothesis concerning the relationship of syringeal structure to vocal abilities. The Auk 1983, 100:853-862.
21. Goller F, Suthers RA. Role of syringeal muscles in controlling the phonology of bird song. J Neurophysiol 1996, 76:287-300.
22. Goller F, Suthers RA. Role of syringeal muscles in gating airflow and sound production in singing brown thrashers. J Neurophysiol 1996, 75:867-876.
23. Larsen ON, Goller F. Direct observation of syringeal muscle function in songbirds and a parrot. J Exp Biol 2002, 205:25-35.
24. Goller F, Larsen ON. A new mechanism of sound generation in songbirds. Proc Natl Acad Sci USA 1997, 94:14787-14791. 10.1073/pnas.94.26.14787, 25115, 9405691.
25. Suthers RA, Wild JM, Kaplan G. Mechanisms of song production in the Australian magpie. J Comp Phys A 2010, 197:45-59.
26. Goller F, Larsen ON. New perspectives on mechanisms of sound generation in songbirds. J Comp Phys A 2002, 188:841-850.
27. Suthers RA, Vallet E, Tanvez AL, Kreutzer M. Bilateral song production in domestic canaries. J Neurobiol 2004, 60:381-393. 10.1002/neu.20040, 15281075.
28. Suthers RA, Zollinger SA. Producing song: the vocal apparatus. Ann NY Acad Sci 2004, 1016:109-129. 10.1196/annals.1298.041, 15313772.
29. Gardner T, Cecchi G, Magnasco M, Laje R, Mindlin G. Simple motor gestures for birdsongs. Phys Rev Lett 2001, 87:208101.
30. Fee MS, Shraiman B, Pesaran B, Mitra PP. The role of nonlinear dynamics of the syrinx in the vocalizations of a songbird. Nature 1998, 395:67-71. 10.1038/25725, 12071206.
31. Elemans CPH, Larsen ON, Hoffmann M, van Leeuwen JL. Quantitative modelling of the biomechanics of the avian syrinx. Animal Biology 2003, 53:183-193.
32. Fee MS. Measurement of the linear and nonlinear mechanical properties of the oscine syrinx: implications for function. J Comp Phys A 2002, 188:829-839.
33. Mindlin G, Gardner T, Goller F, Suthers R. Experimental support for a model of birdsong production. Phys Rev E 2003, 68:041908.
34. Vicario DS. Contributions of syringeal muscles to respiration and vocalization in the zebra finch. J Neurobiol 1991, 22:63-73. 10.1002/neu.480220107, 2010750.
35. Goller F, Cooper BG. Peripheral motor dynamics of song production in the zebra finch. Ann NY Acad Sci 2004, 1016:130-152. 10.1196/annals.1298.009, 15313773.
36. Elemans CPH, Mead AF, Rome LC, Goller F. Superfast vocal muscles control song production in songbirds. PLoS One 2008, 3:e2581. 10.1371/journal.pone.0002581, 2440420, 18612467.
37. Suthers RA, Goller F, Pytte C. The neuromuscular control of birdsong. Phil Trans Roy Soc B 1999, 354:927-939.
38. Riede T, Suthers RA, Fletcher NH, Blevins WE. Songbirds tune their vocal tract to the fundamental frequency of their song. Proc Natl Acad Sci USA 2006, 103:5543-5548. 10.1073/pnas.0601262103, 1459391, 16567614.
39. Nowicki S. Vocal tract resonances in oscine bird sound production: evidence from birdsongs in a helium atmosphere. Nature 1987, 325:53-55. 10.1038/325053a0, 3796738.
40. Ohms VR, Snelderwaard PC, Cate ten C, Beckers GJL. Vocal tract articulation in zebra finches. PLoS One 2010, 5:e11923. 10.1371/journal.pone.0011923, 2912855, 20689831.
41. Williams H, Cynx J, Nottebohm F. Timbre control in zebra finch (Taeniopygia guttata) song syllables. J Comp Psych 1989, 103:366-380.
42. Scharff C, Nottebohm F. A comparative study of the behavioral deficits following lesions of various parts of the zebra finch song system: implications for vocal learning. J Neurosci 1991, 11:2896-2913.
43. Riede T, Fisher JH, Goller F. Sexual dimorphism of the zebra finch syrinx indicates adaptation for high fundamental frequencies in males. PLoS One 2010, 5:e11368. 10.1371/journal.pone.0011368, 2894075, 20614010.
44. Secora KR, Peterson JR, Urbano CM, Chung B, Okanoya K, Cooper BG. Syringeal specialization of frequency control during song production in the Bengalese Finch (Lonchura striata domestica). PLoS One 2012, 7:e34135. 10.1371/journal.pone.0034135, 3313989, 22479543.
45. Chi Z, Margoliash D. Temporal precision and temporal drift in brain and behavior of zebra finch song. Neuron 2001, 32:899-910. 10.1016/S0896-6273(01)00524-4, 11738034.
46. Hahnloser RHR, Kozhevnikov AA, Fee MS. An ultra-sparse code underlies the generation of neural sequences in a songbird. Nature 2002, 419:65-70. 10.1038/nature00974, 12214232.
47. Glaze CM, Troyer TW. Behavioral measurements of a temporally precise motor code for birdsong. J Neurosci 2007, 27:7631-7639. 10.1523/JNEUROSCI.1065-07.2007, 17634357.
48. Elemans CPH, Mead AF, Jakobsen L, Ratcliffe JM. Superfast muscles set maximum call rate in echolocating bats. Science 2011, 333:1885-1888. 10.1126/science.1207309, 21960635.
49. Rome LC. Design and function of superfast muscles: new insights into the physiology of skeletal muscle. Annu Rev Physiol 2006, 68:193-221. 10.1146/annurev.physiol.68.040104.105418, 16460271.
50. Fee MS, Goldberg JH. A hypothesis for basal ganglia-dependent reinforcement learning in the songbird. Neuroscience 2011, 198:152-170. 3221789, 22015923.
51. Suthers RA, Margoliash D. Motor control of birdsong. Curr Opin Neurobiol 2002, 12:684-690. 10.1016/S0959-4388(02)00386-0, 12490259.
52. Riede T, Goller F. Peripheral mechanisms for vocal production in birds - differences and similarities to human speech and singing. Brain Lang 2010, 115:69-80. 10.1016/j.bandl.2009.11.003, 2896990, 20153887.
53. Tchernichovski O, Mitra PP, Lints T, Nottebohm F. Dynamics of the vocal imitation process: how a zebra finch learns its song. Science 2001, 291:2564-2569. 10.1126/science.1058522, 11283361.
54. Lipkind D, Tchernichovski O. Quantification of developmental birdsong learning from the subsyllabic scale to cultural evolution. Proc Natl Acad Sci USA 2011, 108:15572-15579. 10.1073/pnas.1012941108, 3176614, 21436035.
55. Tchernichovski O, Mitra PP. Towards quantification of vocal imitation in the zebra finch. J Comp Phys A 2002, 188:867-878.
56. Tchernichovski O, Nottebohm F, Ho C, Pesaran B, Mitra P. A procedure for an automated measurement of song similarity. Anim Behav 2000, 59:1167-1176. 10.1006/anbe.1999.1416, 10877896.
57. Arneodo EM, Perl YS, Goller F, Mindlin GB. Prosthetic avian vocal organ controlled by a freely behaving bird based on a low dimensional model of the biomechanical periphery. PLoS Comput Biol 2012, 8:e1002546. 10.1371/journal.pcbi.1002546, 3386162, 22761555.
58. Laje R, Sciamarella D, Zanella J, Mindlin GB. Bilateral source acoustic interaction in a syrinx model of an oscine bird. Phys Rev E 2008, 77:011912.
59. Laje R, Gardner T, Mindlin G. Neuromuscular control of vocalizations in birdsong: a model. Phys Rev E 2002, 65:051921.
60. Wild JM. Functional neuroanatomy of the sensorimotor control of singing. Ann NY Acad Sci 2004, 1016:438-462. 10.1196/annals.1298.016, 15313789.
61. Vicario DS, Nottebohm F. Organization of the zebra finch song control system: I. Representation of syringeal muscles in the hypoglossal nucleus. J Comp Neurol 1988, 271:346-354. 10.1002/cne.902710305, 3385013.
62. Roberts TF, Klein ME, Kubke MF, Wild JM, Mooney R. Telencephalic neurons monosynaptically link brainstem and forebrain premotor networks necessary for song. J Neurosci 2008, 28:3479-3489. 10.1523/JNEUROSCI.0177-08.2008, 2843410, 18367614.
63. Kubke MF, Yazaki-Sugiyama Y, Mooney R, Wild JM. Physiology of neuronal subtypes in the respiratory-vocal integration nucleus retroamigualis of the male zebra finch. J Neurophysiol 2005, 94:2379-2390. 10.1152/jn.00257.2005, 15928060.
64. Sober SJ, Wohlgemuth MJ, Brainard MS. Central contributions to acoustic variation in birdsong. J Neurosci 2008, 28:10370-10379. 10.1523/JNEUROSCI.2448-08.2008, 2613831, 18842896.
65. Ting LH, McKay JL. Neuromechanics of muscle synergies for posture and movement. Curr Opin Neurobiol 2007, 17:622-628. 10.1016/j.conb.2008.01.002, 18304801.
66. Chvatal SA, Ting LH. Voluntary and reactive recruitment of locomotor muscle synergies during perturbed walking. J Neurosci 2012, 32:12237-12250. 10.1523/JNEUROSCI.6344-11.2012, 22933805.
67. d'Avella A, Bizzi E. Shared and specific muscle synergies in natural motor behaviors. Proc Natl Acad Sci USA 2005, 102:3076-3081. 10.1073/pnas.0500199102, 549495, 15708969.
68. Ziegler A, Mietchen D, Faber C, Hausen von W, Schöbel C, Sellerer M, Ziegler A. Effectively incorporating selected multimedia content into medical publications. BMC Medicine 2011, 9:17. 10.1186/1741-7015-9-17, 3040697, 21329532.
69. Kumar P, Ziegler A, Grahn A, Hee CS, Ziegler A. Leaving the structural ivory tower, assisted by interactive 3D PDF. Trends Biochem Sci 2010, 35:419-422. 10.1016/j.tibs.2010.03.008, 20541422.
70. Robling AG, Castillo AB, Turner CH. Biomechanical and molecular regulation of bone remodeling. Annu Rev Biomed Eng 2006, 8:455-498. 10.1146/annurev.bioeng.8.061505.095721, 16834564.
71. Williams H, Crane LA, Hale TK, Esposito MA, Nottebohm F. Right-side dominance for song control in the zebra finch. J Neurobiol 1992, 23:1006-1020. 10.1002/neu.480230807, 1460461.
72. King AS. Apparatus respiratorius. Handbook of Avian Anatomy 1993, 23:257-300. Cambridge, MA: Nuttall Ornithological Club, Baumel JJ, King AS, Breazile JE, Evans HE, Vanden Berge JC, 2.
73. Riede T, Goller F. Functional morphology of the sound-generating labia in the syrinx of two songbird species. J Anat 2010, 216:23-36. 10.1111/j.1469-7580.2009.01161.x, 2807973,2807973, 19900184.
74. Elemans CPH, Spierts ILY, Hendriks M, Schipper H, Müller UK, van Leeuwen JL. Syringeal muscles fit the trill in ring doves (Streptopelia risoria L.). J Exp Biol 2006, 209:965-977. 10.1242/jeb.02066, 16481585.
75. Alexander RM. Optima for Animals 1996, Princeton, NJ: Princeton University Press, Revised.
76. Alexander RM. Animal Mechanics 1983, Oxford: Blackwell Scientific Publication, Second.
77. Vincent J. Structural Biomaterials 1990, Princeton, NJ: Princeton University Press.
78. Draganoiu TI, Nagle L, Kreutzer M. Directional female preference for an exaggerated male trait in canary (Serinus canaria) song. Proc Roy Soc Lond B 2002, 269:2525-2531.
79. Podos J. A performance constraint on the evolution of trilled vocalizations in a songbird family (Passeriformes: Emberizidae). Evolution 1997, 51:537-551.
80. Alatalo RV, Glynn C, Lundberg A. Singing rate and female attraction in the pied flycatcher: an experiment. Anim Behav 1990, 39:601-603.
81. Gil D, Gahr M. The honesty of bird song: multiple constraints for multiple traits. Trends Ecol Evol 2002, 17:133-141.
82. Wasserman FE, Cigliano JA. Song output and stimulation of the female in white-throated sparrows. Behav Ecol Sociobiol 1991, 29:55-59.
83. Podos J, Huber SK, Taft B. Bird song: the interface of evolution and mechanism. Ann Rev Ecol Evol Syst 2004, 35:55-87.
84. Young IS, Rome LC. Mutually exclusive muscle designs: the power output of the locomotory and sonic muscles of the oyster toadfish (Opsanus tau). Proc Roy Soc Lond B 2001, 268:1965-1970.
85. Rome LC, Lindstedt SL. The quest for speed: muscles built for high-frequency contractions. News Physiol Sci 1998, 13:261-268.
86. Rome LC, Syme DA, Hollingworth S, Lindstedt SL, Baylor SM. The whistle and the rattle: the design of sound producing muscles. Proc Natl Acad Sci USA 1996, 93:8095-8100. 10.1073/pnas.93.15.8095, 38881, 8755609.
87. Ludlow CL. Central nervous system control of the laryngeal muscles in humans. Resp Phys NeuroBiol 2005, 147:205-222.
88. Titze IR. Principles of Voice Production 1994, Englewood Cliffs, NJ: Prentice-Hall, Inc.
89. Boles WE. Fossil songbirds (Passeriformes) from the early Eocene of Australia. Emu 1997, 97:43-50.
90. Barker FK, Cibois A, Schikler P, Feinstein J, Cracraft J. Phylogeny and diversification of the largest avian radiation. Proc Natl Acad Sci USA 2004, 101:11040-11045. 10.1073/pnas.0401892101, 503738, 15263073.
91. Greenewalt CH. Bird Song: Acoustics and Physiology 1968, Washington DC, USA: Smithsonian Institute.
92. Rüppell W. Physiologie und akustik der vogelstimme. J Ornithol 1933, 81:433-542.
93. Elemans CPH, Muller M, Larsen ON, van Leeuwen JL. Amplitude and frequency modulation control of sound production in a mechanical model of the avian syrinx. J Exp Biol 2009, 212:1212-1224. 10.1242/jeb.026872, 19329754.
94. Brittan-Powell EF, Dooling RJ, Larsen ON, Heaton JT. Mechanisms of vocal production in budgerigars (Melopsittacus undulatus). J Acoust Soc Am 1997, 101:578-589. 10.1121/1.418121, 9000746.
95. Elemans CPH, Zaccarelli R, Herzel H. Biomechanics and control of vocalization in a non-songbird. J R Soc Interface 2008, 5:691-703. 10.1098/rsif.2007.1237, 2607454, 17999946.
96. Amador A, Goller F, Mindlin GB. Frequency modulation during song in a suboscine does not require vocal muscles. J Neurophys 2008, 99:2383-2389.
97. Elemans CPH, Spierts ILY, Müller UK, van Leeuwen JL, Goller F. Bird song: superfast muscles control dove's trill. Nature 2004, 431:146. 10.1038/431146a, 15356620.
98. Loeb GE, Gans C. Electromyography for Experimentalists 1986, Chicago, IL: The University of Chicago Press, First.
99. Suthers RA. Peripheral vocal mechanisms in birds: are songbirds special?. Neth J Zool 2001, 51:217-242.
100. Williams H. Choreography of song, dance and beak movements in the zebra finch (Taeniopygia guttata). J Exp Biol 2001, 204:3497-3506.
101. Daley M, Goller F. Tracheal length changes during zebra finch song and their possible role in upper vocal tract filtering. J Neurobiol 2004, 59:319-330. 10.1002/neu.10332, 15146548.
102. Youngren OM, Peek FW, Phillips RE. Repetitive vocalizations evoked by local electrical stimulation of avian brains. Brain Behav Evol 1974, 9:393-407. 10.1159/000123679, 4447880.
103. Gaunt AS, Gaunt SLL. Mechanics of the syrinx in Gallus gallus. II. Electromyographic studies of ad libitum vocalizations. J Morphol 1977, 152:1-19. 10.1002/jmor.1051520102, 870697.
104. Gaunt AS, Gaunt SLL, Casey RM. Syringeal mechanics reassessed: evidence from Streptopelia. Auk 1982, 99:474-494.
105. Goller F, Larsen ON. In situ biomechanics of the syrinx and sound generation in pigeons. J Exp Biol 1997, 200:2165-2176.
106. Miskimen M. Sound production in passerine birds. Auk 1951, 68:493-504.
107. Suthers RA, Hector DH. Mechanism for the production of echolocating clicks by the grey swiftlet, Collocalia spodiopygia. J Comp Physiol A 1982, 148:457-470.
108. Suthers RA, Hector DH. The physiology of vocalization by the echolocating oilbird, Steatornis caripensis. J Comp Physiol A 1985, 156:243-266.
109. Smith DG. The role of the sternotrachealis muscles in bird song production. Auk 1977, 94:152-155.
110. Miskimen M. Absence of syrinx in the turkey vulture (Cathartes aura). Auk 1957, 74:104-105.
111. Garitano-Zavala A. Evolutionary loss of the extrinsic syringeal muscle sternotrachealis in Darwin's nothura (Nothura darwinii). Auk 2009, 126:134-140.
112. Gribble PL, Mullin LI, Cothros N, Mattar A. Role of cocontraction in arm movement accuracy. J Neurophys 2003, 89:2396-2405.
113. d'Avella A, Portone A, Fernandez L, Lacquaniti F. Control of fast-reaching movements by muscle synergy combinations. J Neurosci 2006, 26:7791-7810. 10.1523/JNEUROSCI.0830-06.2006, 16870725.
114. Hogan N. Adaptive control of mechanical impedance by coactivation of antagonist muscles. IEEE Trans Autom Contr 1984, 29:681-690.
115. Berwick RC, Okanoya K, Beckers GJL, Bolhuis JJ. Songs to syntax: the linguistics of birdsong. Trends Cogn Sci 2011, 15:113-121. 10.1016/j.tics.2011.01.002, 21296608.
116. White SA. Genes and vocal learning. Brain Lang 2010, 115:21-28. 10.1016/j.bandl.2009.10.002, 2888939, 19913899.
117. Metscher BD. MicroCT for comparative morphology: simple staining methods allow high-contrast 3D imaging of diverse non-mineralized animal tissues. BMC Physiol 2009, 9:11. 10.1186/1472-6793-9-11, 2717911, 19545439.
118. Metscher BD. MicroCT for developmental biology: a versatile tool for high-contrast 3D imaging at histological resolutions. Dev Dyn 2009, 238:632-640. 10.1002/dvdy.21857, 19235724.
119. Jeffery NS, Stephenson RS, Gallagher JA, Jarvis JC, Cox PG. Micro-computed tomography with iodine staining resolves the arrangement of muscle fibres. J Biomech 2011, 44:189-192. 10.1016/j.jbiomech.2010.08.027, 20846653.
120. Owen R. On the Anatomy of Vertebrates 1866, London: Longmans, Green and Co.
121. Tyzack JK. Dragging (and zooming and rotating) publication of 3D molecular structures into the 21st century. Trends Biochem Sci 2008, 33:405-407. 10.1016/j.tibs.2008.07.001, 18707889.
122. Kumar P, Ziegler A, Ziegler J, Uchanska-Ziegler B, Ziegler A. Grasping molecular structures through publication-integrated 3D models. Trends Biochem Sci 2008, 33:408-412. 10.1016/j.tibs.2008.06.004, 18672371.
123. Dürrwang R. Funktionelle Biologie, Anatomie und Physiologie der Vogelstimme. PhD thesis 1974, Universität Basel.
124. Köditz W. Uber die Syrinx einiger clamatores und auslandischer oscines. Z Wiss Zool 1925, 126:70-144.
125. Chamberlain DR, Gross WB, Cornwell W, Mosby HS. Syringeal anatomy in the common crow. Auk 1968, 85:244-252.
126. Warner RW. The anatomy of the syrinx in passerine birds. J Zool 1972, 168:381-393.
127. Gaunt AS, Wells MK. Models of syringeal mechanisms. Am Zool 1973, 13:1227-1247.
128. Brackenbury JH. The structural basis of voice production and its relationship to sound characteristics. Acoustic Communication in Birds 1982, 53-73. New York: Academic Press, Kroodsma DE, Miller DH.
129. Häcker V. Der Gesang der Vögel: Anatomische und biologische Grundlagen 1900, Jena, Germany: Gustav Fischer.
130. Baumel JJ, King AS, Breazile JE, Evans HE, Vanden Berge JC. Handbook of Avian Anatomy 1993, Cambridge: Nuttall Ornithological Club, 2.