Chibchella nigrospecula

(2 males recorded) Two males were recorded with high frequency capable equipment. Since they were at different temperatures (96-1, 19.8°C; 97-1, 25.5°C) most song measures are given separately.

Songs were mostly a double zip (Fig. 38B), but sometimes a single or rarely 3 zips (Fig. 38A). For 14 consecutive calls of 96-1 (9 double-zip, 5 single-zip) mean call period was 8.3 s (range: 2.6-18.6 s). Top song rate observed in this male was about 8/min. Single zips often began his calling bout, changing to doubles later on. For double zips one can determine a mean zip period: this was longer for the colder singer than for the warmer: (96-1), 180 ms, range 128-246 (n = 9 calls): (97-1) 126 ms, range 115-146 (n = 8 calls).

Each zip is a train of 7-14 temporally discrete transient pulses, the train lasting about 50 ms (Fig. 38B). The average number of pulses per train was 7.9 (96-1); 13.4 (97-1). Mean pulse train duration was (first zip of 2-zip calls): 50.5 ms (961); 49.5 ms (97-1). The mean pulse rate, measured per 2 consecutive pulses early in the train, was: 212/s, (range 173230), 96-1; 286/s. (range 271-314), 97-1; but pulse periods are quite variable within individuals.

The song is easily audible and in keeping with this, much spectral energy is in the audio range (Fig. 38D). The pulse waveform (Fig. 38C) is complex, creating a band spectrum that extends from 5-30 kHz. Mean band width per 20 dB down was 4.3-29.0 kHz (96-1) and 5.6-31.9 kHz (97-1). One male had its most intense peak in the audio at 9.8 kHz (96-1) while the other was most intense at 20 kHz. But these maximum peak differences, though consistent, were only marginally greater than other spectral components over the same individual's band.

This species was also observed producing bouts of calling tremulation while caged in the laboratory, bouts that alternated with intervals of acoustic calling. [1]

參考文獻