In the following we briefly analyze and compare voice of the two races of Brown-chested Jungle-flycatcher (Rhinomyias brunneatus). We also try to quantify the extent of any vocal differences using the criteria proposed by Tobias et al. (2010), as a support for taxonomic review. We have made use of sound recordings available on-line from Xeno Canto (XC).
Nominate seems to have a short song and a more elaborated alternative song. Short song starts with 1-3 short very high-pitched notes (c. 7-8kHz, hardly audible) followed by remarkably low-pitched whistles (c. 2-3 kHz)(typically 2 followed by a series of 2-4 notes which are slightly higher-pitched and may accelerate towards the end). Duration of the low-pitched phrase c. 1 - 1.2s. Alternative song, only occasionally heard, is a continuous series of trills and repeated notes.
nicobaricus: There are apparently no recordings available on-line, but there is a description in The Ripley Guide including sonogram of 3 examples (Rasmussen & Anderton 2012). These are somewhat different (but at the same time are rather similar considering the extremely disjunct ranges of both taxa, suggesting there is indeed a close relationship): The introductory high-pitched notes are not described (or unnoticed, as some light specks on the sonograms may be an indication that these introductory notes are lower-pitched, c. 4-6.5kHz ??). The song phrase of low-pitched whistles has a duration of c. 1.2 - 1.5s. Whistles start slowly but typically accelerate and may end in a short trill. Freq. range 1.5 - 2.9kHz.
More recordings are needed to confirm whether most songs fall within the ranges mentioned above. If so, vocal difference could be scored as follows: Song of nicobaricus lacks high-pitched intro notes (or in a lower frequency range?) (2), whistled phrase is slightly longer with more notes (score 2-3) and has a slightly higher pace towards the end (score 2). This would lead to a total vocal score of 4.
This note was finalized on 7th May 2016, using sound recordings available on-line at that moment. We would like to thank in particular the sound recordists who placed their recordings for this species on XC: Qin Huang, Frank Lambert, Yong Ding Li and Jonathan Martinez.
Rasmussen, P.C. & Anderton, J.C. (2012). Birds of South Asia: the Ripley Guide. Second edition. Lynx Edicions, Barcelona.
Tobias, J.A., Seddon, N., Spottiswoode, C.N., Pilgrim, J.D., Fishpool, L.D.C. & Collar, N.J. (2010). Quantitative criteria for species delimitation. Ibis 152(4): 724–746.
More Information: on318_brown-chested_jungle-flycatcher.pdf