High-speed video analysis of wing-snapping in two manakin clades(Pipridae: Aves)

Abstract

SUMMARYBasic kinematic and detailed physical mechanisms of avian, non-vocal sound production are both unknown. Here, for the first time, field-generated high-speed video recordings and acoustic analyses are used to test numerous competing hypotheses of the kinematics underlying sonations, or non-vocal communicative sounds, produced by two genera of Pipridae, Manacus and Pipra (Aves). Eleven behaviorally and acoustically distinct sonations are characterized, five of which fall into a specific acoustic class of relatively loud, brief, broad-frequency sound pulses, or snaps. The hypothesis that one kinematic mechanism of snap production is used within and between birds in general, and manakins specifically, is rejected. Instead, it is verified that three of four competing hypotheses of the kinematic mechanisms used for producing snaps, namely: (1) above-the-back wing-against-wing claps, (2)wing-against-body claps and (3) wing-into-air flicks, are employed between these two clades, and a fourth mechanism, (4) wing-against-tail feather interactions, is discovered. The kinematic mechanisms used to produce snaps are invariable within each identified sonation, despite the fact that a diversity of kinematic mechanisms are used among sonations. The other six sonations described are produced by kinematic mechanisms distinct from those used to create snaps, but are difficult to distinguish from each other and from the kinematics of flight. These results provide the first detailed kinematic information on mechanisms of sonation in birds in general, and the Pipridae specifically. Further, these results provide the first evidence that acoustically similar avian sonations, such as brief, broad frequency snaps, can be produced by diverse kinematic means, both among and within species. The use of high-speed video recordings in the field in a comparative manner documents the diversity of kinematic mechanisms used to sonate, and uncovers a hidden, sexually selected radiation of behavioral and communicative diversity in the Pipridae.

Female mate choice based upon male motor performance

“…In the New World manakins (Pipridae), males of many species produce non-vocal courtship sounds by extraordinary movements of their wings (Bostwick and Prum, 2003;Bostwick and Prum, 2005). Several of these sounds are produced as birds slap the dorsal surfaces of their wings together at very high repetition rates, close to the contraction speed limits of vertebrate muscle.…”

“…For example, red-capped manakin, Pipra mentalis, male courtship involves backward "slides" along a branch by tiny, imperceptibly fast movements of the male's feet (Prum 1990). Other manakin males incorporate very rapid short flights and acrobatic hops in their displays to females, often occurring in synchrony with sonation (Prum and Johnson, 1987;Thery, 1990;Bostwick and Prum, 2003). High-speed hops, pivots and glides and other unusual movements occur in the courtship displays of males in many species of the birds of paradise (Aves: Paradisaeidae).…”

Determination of the wingsnap sonation mechanism of the Golden-collared manakin (Manacus vitellinus)

“…These are explosive sounds characterized by a broad frequency spectrum and lack of tonal features; they are very loud and can be heard from hundreds of meters away. A previous study using highspeed videography has shown that these sounds are produced with a very rapid upstroke motion of the wings above the back (Bostwick and Prum, 2003).…”

“…We focused on two mechanical sounds that M. vitellinus males produce during courtship displays: the single wingsnap and the rollsnap (Chapman, 1935;Snow, 1962;Skutch, 1969;Schultz and Schlinger, 1999;Bostwick and Prum, 2003;Schlinger et al, 2013). These are explosive sounds characterized by a broad frequency spectrum and lack of tonal features; they are very loud and can be heard from hundreds of meters away.…”

“…The speed of the birds' movements is so quick that unambiguously determining the origin of the sonation is difficult. Using high-speed videography (up to 500 frames s −1 ), Bostwick and Prum (2003) showed that wingsnaps are produced as the wings make contact over the back of the bird. Their methodology, however, did not allow them to discriminate their three hypotheses for sound production: (1) whip-like sonic waves produced by the wing (or part of the wing) moving faster than the speed of sound; (2) vacuum-created pressure claps created when a low pressure center is suddenly collapsed; or (3) percussion resulting from forceful impact of the wings.…”