“…For example, a commonly used experimental manipulation to induce adaptive changes in the acoustic structure of adult song elements was first reported in BFs ( Tumer and Brainard, 2007 ) and the neural mechanisms of such song changes have been intensively studied in both BFs and ZFs ( Andalman and Fee, 2009 ; Charlesworth et al, 2012 ; Gadagkar et al, 2016 ; Hisey et al, 2018 ; Xiao et al, 2018 ; Tachibana et al, 2022 ). Because of the vocal learning ability and underlying neural circuits largely shared between these species, most studies have used them with little attention to species differences, although a limited number of studies took advantage of variable syllable sequencing in BF songs ( Okanoya, 2004 ; Warren et al, 2012 ; Lipkind et al, 2013 ; Polomova et al, 2019 ; Veit et al, 2021 ). The current study systematically compared the behavioral properties of singing between the two species and investigated the underlying mechanisms, revealing previously unknown differences between them.…”