Overview of terminology describing ossified structural elements of the songbird syrinx. Alternative nomenclatures of previous authors [16, 18, 19, 28, 43, 52, 72, 73, 106, 123–129]. The system that we adopt in this study is a combination of terminologies proposed by Häcker , Chamberlain and colleagues , and Warner . Note in particular the approach proposed by Ames , which emphasizes the microstructure of individual syringeal bones that make up the tympanum. Abbreviations as listed in Table 1.