BioAcoustica is a free, open repository of wildlife sound recordings from the Natural History Museum, London.
Taxonomic index of the BioAcoustica collection
Acoustic and biological measurements in the BioAcoustica collection
Recording annotations from ann-o-mate
The specimens that recordings are of, from the collections
Where the specimens that recordings are of were collected, not where the sound was recorded
(5 males recorded) Five ales of T. fasciatus were recorded. Four specimens were from Misahualli and one from Primavera. The species has a very low duty cycle. A male in the lab (88-2) was timed with a stopwatch over 50 consecutive calls and showed an average between-call down time of 34.5 s. The average song interval of another caged male (20°C, 88-1) was similar: 37.4 s (n = 15 consecutive calls). Eight recorded calls of this second male (88-1) had a mean duration of 54.2 ms, on the basis of which we calculate a call duty cycle of only 0.15 %. Pooling available records of all five males gave an average song duration of 58 ms. In real time little is detected by the human ear, just a faint tick, without any apparent infrastructure (Fig. 36A). Slowed by a factor of 2, the tick sounds musical and is heard as a chirp. Within each tick are three ragged pulse trains each pulse having a very sinsusoidal waveform (Fig. 36 B,C). Averaging for the 5 males, despite the rather wide range of recording temperatures (18-24°C), the successive trains have incrementing mean durations of 6.3.6.8 and 9.6 ms. The final train was always clearly longer than the others for all males. In four of five singers there was an increment in peak amplitude of successive trains. For the male incorporating the most lengthy (prolonged) pulse (Fig. 36E) there was a uniform maximum amplitude for all 3 pulse trains of his tick. Coincident with the highest temperature (24°C) the trains had their longest durations: 7, 10, 13 ms. Variable pulse duration is a feature of this species. Shorter initial pulses grow longer and eventually become more sustained. These pulses are not consistent in number per train, or in duration between individuals, but there is some similarity within the same individuals. Comparison of Fig36 B, E, F illustrates this AM variation using the final pulse from a call of each of three different males. The male of Fig. 36 E achieved the most sustained output, consistently producing a final pulse lasting >6 MS at a stable high amplitude. Little variation occurred between the five males in the high-Q, carrier frequency. A narrow peak is at 24 kHz (mean 24.1 kHz, range 23.2-25.0 kHz) (Fig. 36D). No energy within 30 dB of the principal peak occurs beyond 30 kHz. We detected a very slight upward frequency modulation (FM): the peak moves slightly upward over the three pulses: from 23 to 24 kHz.