In the following we briefly analyze and compare voice of the different races of Yellow-bellied Prinia (Prinia flaviventris). 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 of all races is a short lively phrase descending in pitch. Some examples from west to east (illustrated with multiple sonograms in the pdf version of this note): Pakistan (sindiana), N India (flaviventris), Peninsular Malaysia (rafflesi), Indonesia (rafflesi), Borneo (latrunculus), Cambodia (delacouri), NE Vietnam (sonitans), S China (sonitans), E China (sonitans) and Taiwan (sonitans).
There are slight regional differences, which may be larger than individual differences within each subspecies. There is however no clear vocal difference between sonitans/latrunculus as one combined group (denominated as E group in HBW Alive: Madge et al. 2016) and the rest.
On the contrary, there IS a vocal difference between sonitans (NE Vietnam, S and E China, Taiwan) and the rest: the former has a clearly longer song phrase (phrase length 1.1 - 1.5s vs. 0.5 - 0.9s, score 2-3).
To a lesser extent, sindiana stands vocally apart as it has a much more eerie tinkling song compared to other races (a single recording from N India is however somewhat intermediate). This could tentatively be given a score of 1-2.
As for latrunculus, vocal differences with neighbouring rafflesi are subtle: it would seem that one can at least separate them with 90% confidence as latrunculus has a well-spaced first note which is quite emphasized, versus a first note that is rather a silent start of the downslurred song phrase in rafflesi. Given there is some slight overlap, this could be given a score of 1.
This note was finalized on 16th February 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.
Madge, S. (2016). Yellow-bellied Prinia (Prinia flaviventris). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/58590 on 16 February 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: on228_yellow-bellied_prinia.pdf