In the following we briefly analyze and compare voice of the different races of Lesser Shortwing (Brachypteryx leucophris). 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).
Song is rather similar over its entire range, typically starting with a few pure notes on about same pitch and gradually increasing pitch range, with notes more or less alternating at increasingly lower and higher pitch. Song strophe often ends with some more snarling or dissonant notes.
Some examples (illustrated with multiple sonograms in the pdf version of this note): nipalensis, carolinae, wrayi, langbianensis, leucophrys (Sumatra and Java).
Song strophe structure is clearly the same for all races, and basic sound parameters (phrase length, number of notes, min./max. frequency etc.) are very similar as well. Song phrases on Java and adjacent islands to the east possibly slightly longer in duration, but Sumatran birds (presumably of the same taxon) don't show this difference. Effect of playback may be an influencing factor.
The uniformity of song between the different races is even more striking considering the extreme variation in voice between most races of closely related White-browed Shortwing Brachypteryx montana (Boesman 2016).
This note was finalized on 10th May 2016, using sound recordings available on-line at that moment. We would like to thank in particular the many sound recordists who placed their recordings for this species on XC.
Boesman, P. (2016). Notes on the vocalizations of White-browed Shortwing (Brachypteryx montana). HBW Alive Ornithological Note 322. In: Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/1252522 on 20 October 2016).
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: on323_lesser_shortwing.pdf