Three distinctive call types were heard in differnet areas; type one calls, each a brief 'gek', from the base of the oak-laurel forest at 1100-1200 m to a ridgetop site near camp four at c. 1700; type two calls, each a longer 'gegger', around camp four at 1800-1930 m; and type three calls (not recorded)., each abrief 'gan', at a dense chorus on the summit knoll at c. 2200 m. Type one and two calls are described below. They differ in dominant frequency, duration, pulse rate and number of pulses. Some of the differences may be temperature effects (decrease in temperature usually decreases frequency and pulse rate, increases duration), some may also be due to differences in body size (small frogs usually have high calls), but it also seems likely that a degree of genetic divergence has taken place between local populations (see variation).
Type One Call: BM 1978.1618, air temperature 20oC. The call is a single note 0.08 sec in duration, compsoed of about ten pulses, at a rate of c. 130 pulses per second. Dominant frequency is 2.8-3.4khz, there is less intense sound energy flanking the dominant at 4.4-4.1khz. A weak fundamental frequency ranges from 80-1200 hz. A distinct harmonic is at 6.0-6.6 khz, dropping to 5.8-6.4 khz. Weak frequency modulation is evident in the harmonic and may be presumed present in the dominant (fig. 2 d, e).
Type two call, specimen escaped (BM 1978.97, a female, collected at site), estimated air temperature 17-18oC. The call is a single note 0.58 sec in duration, composed of 51 pulses, at a rate of 93 pulses per second. Dominant frequency is 1.8-2.8 khz, flanked by less intense energy bands as 1.3-1.7khz and 3.0-3.4khz. A weak fundamental is present at 80-600 hz. A distinct harmonic is at 4.3-5.0 khz and another at 6.6-7.0 khz. Weak frequency modulation is ebident in the harmonic. [1]
References
- . Some new frogs from Sarawak. Amphibia-Reptilia. 1984;4(2):103 - 115. Available at: http://booksandjournals.brillonline.com/content/10.1163/156853883x00021.