In the following we briefly analyze and compare voice of the different races of Polynesian Starling (Aplonis tabuensis). 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) and Macaulay Library (ML).
An overview of vocalization per region (illustrated with multiple sonograms in the pdf version of this note):
Fiji group: song is fairly simple, consisting of 1 (or occasionally 2) high-pitched whistles followed by a few (1-3) much lower-pitched whistles.
Samoa group (excl. manuae): song consists of 1-2 whistles and 1-3 trills. These trills are seemingly always present (while absent in birds of the Fiji group).
manuae: has sometimes trills in its song, and song may be slightly longer with more whistled notes (it is however not obviously higher-pitched than the Samoa group, contra Pratt et al. 2016).
Given the variability within especially song of the Samoa group and race manuae, these two groups seem to differ less reciprocally than in comparison with the Fiji group, the latter being much more uniform and seemingly lacking trills. manuae may have on average the highest number of notes in its song phrase.
All in all, vocal differences of the three groups are rather minor. If a vocal score should be given, then Fiji group has a prominent pitch drop (start freq. minus end frequency, score 2) and no trills (1). manuae has on average more notes per song phrase (1) vs both other groups.
This note was finalized on 25th July 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 and ML: Michael Anderson, Matthias Feuersenger, Phil Gregory, Samuel Jones, John Mittermeier, Douglas Pratt, Joshua Seamon, Mark Todd and Bobby Wilcox.
Pratt, H.D. & Mittermeier, J.C. (2016). Notes on the natural history, taxonomy, and conservation of the endemic avifauna of the Samoan archipelago. Wilson J. Orn. 128(2): 217–241.
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: on411_polynesian_starling.pdf