Bioacoustics of Oncotympana obesa

Song ( Figure 10 ) Recordings of male calling song totalling 320 s were taken at the type locality (the holotype male is illustrated). Males were recorded producing song in phrases of 4–11 s duration (4–6 most common) comprised of two-syllable echemes repeated at about 5.2– 6.5 echemes/s. Note that such values are commonly dependent on temperature. The syllables within each echeme contain strongly contrasting sound frequencies. The first syllable contains most of its sound energy within the range 7–15 kHz, with a peak at about 10 kHz, while the second syllable, which is nearly an order of magnitude quieter than the first, contains sound energy with a peak of 4.5 kHz and a broad shoulder of quieter frequencies ranging from 2–16 kHz. The fundamental sound pulses are produced at about 225/s in the first syllable, which lasts 0.04 s , and slightly faster at about 235/s in the second syllable which is twice as long. This species sang from low stations on tree trunks in the forest understory in low light conditions, as early as 7.00am. Males could be attracted by mouth-clicks or finger-snaps produced a fraction of a second after the end of the complete song phrase. Immediately after hearing the response, the male would flick his wings with a synchronised timbal click, before turning or moving in the direction of the sound. Several specimens from the paratype series were collected with this technique.