(A) Species included in our study, with common names in boldface typesetting and scientific names in italic typesetting. A brief description of each species’ display and reason for inclusion in the study is described. Photos with permission from Nick Athanas. (B) Illustration of the three main wing muscles in a golden-collared manakin that are involved in the production of the roll-snap. These include (i) the supracoracoideus (SC), which raises the wing by elevating the humerus; (ii) the pectoralis (PEC), which lowers the wing by depressing the humerus, and (iii) the scapulohumeralis caudalis (SH), which retracts the wing via the humerus (Biewener, 2011; Dial, 1992; Dial et al., 1991). Note that the SC is a darker shade of pink, compared to the PEC and SH, because the SC lies deep to the PEC. Scientific illustrations of these muscles can be found elsewhere (Welch and Altshuler, 2009; George and Berger, 1966). This schematic is modified with permission from Schlinger, et al. (Schlinger et al., 2013).