Figure 2

Sonagraphic measurements taken from trill verse types (a) and warbling verse types (b), the latter being composed of repeated syllables (syl1, syl2, syl3) of alternating elements (AB, CD, EF); recordings J.M.: 4088: China, Shaanxi Taibai Shan; 1707: Nepal, Thankur N Dhorpatan.