Bisonic mechanical wing songs and complex kinematics in aerial displays of the Subtropical Doradito (Pseudocolopteryx acutipennis)

JORDAN, EMILIO A; ARETA, JUAN I

INTEGRATIVE AND COMPARATIVE BIOLOGY

OXFORD UNIV PRESS INC

Lugar: Oxford; Año: 2020 vol. 60 p. 1173 - 1187

1540-7063

Loudmechanical sounds with a communication role are called sonations. MaleSubtropical Doraditos (Pseudocolopteryxacutipennis) exhibit five conspicuously modified primaries suspected of sonating. Here we 1) describe feathermodifications, 2) describe three different territorial/aggressive contexts forthese sounds: One-perch aerial displays,Two-perch aerial displays and Chukrut pursuits, 3) investigate thekinematics of the most common display (One-perchaerial display) and the physical mechanisms of sonation using synchronizedhigh-speed video and audio, and 4) assess the roles of modified wing feathersin all contexts by experimental manipulation in four individuals. Primaries p3 to p7 were modified in adult males but notin females: p3 was pointed with a reduced distal third to the outer vane; p4and p5 were slim and falciform with pointed tips curved outwards; p6 was broad,massive and subtly S-shaped, with a spatulate tip; and p7 was large with thedistal third of the outer vane abruptly reduced, and the inner vane with ashallow concave sub-apical emargination. One-perch aerial displays consisted ofperched short nasal introductory syllables accelerating until the birdperformed a super-rapid circular flight of ∽15 cm in diameter from and to the same branch, during which twosyringeal syllables and three mechanical syllables (chik... chik.... chik-chik frrrottt). The syllables were produced during rapid downstrokes by flutteringfeathers and were bisonic, being conformed by two simultaneous main tonal,flat, narrow band sounds: a low-pitched note (f0 ∽c. 1 kHz) and ahigh-pitched note (f0 ∽c. 3.7 kHz). p7 is the necessary and sufficient sound source of thelow-pitched note (removal of p7 caused the sound to disappear) and p3 is thesound source of the high-pitched note, being necessary but perhaps notsufficient (removal of p3 caused the sound to disappear); the other modifiedfeathers seem involved in different roles related to either producing thesonation (p4 and p5 interacting with p3) or allowing it (p6 raising dorsallyletting p7 flutter freely; removal of p6 did not affect sound production). Thespecialized shape of p6 might be compromised to allow sonation of p7 without losingflight functionality. Sonations in Subtropical Doraditos occupy the position ofthe vocal flourish in the songs of other Pseudocolopteryxsuggesting the evolutionary replacement of vocal by mechanical sounds. Wepropose that wing songs in flying birds may be constrained to occur intemporally broken patterns due to intrinsic features of flapped flight andstructurally constrained by the demands of creating an airfoil.<!-- /* Font Definitions */@font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-520092929 1073786111 9 0 415 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin-top:0in;margin-right:0in;margin-bottom:8.0pt;margin-left:0in;line-height:107%;mso-pagination:widow-orphan;font-size:11.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:ES-AR;}span.tlid-translation{mso-style-name:tlid-translation;mso-style-unhide:no;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:11.0pt;mso-ansi-font-size:11.0pt;mso-bidi-font-size:11.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:ES-AR;}.MsoPapDefault{mso-style-type:export-only;margin-bottom:8.0pt;line-height:107%;}size:8.5in 11.0in;margin:1.0in 1.25in 1.0in 1.25in;mso-header-margin:.5in;mso-footer-margin:.5in;mso-paper-source:0;}div.WordSection1{page:WordSection1;}