In the following I briefly analyze and compare the voice of the three races of Long-billed Green Sunbird (Cinnyris notatus). I 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. I have made use of sound recordings available online at Xeno-Canto (XC), and the Chappuis CDs (Huguet & Chappuis 2003).
An overview of vocalizations per race (illustrated with multiple sonograms in the .pdf version of this note):
moebii (Grand Comoro): Song: a continuous fast tinkling or twittering for long periods, pace somewhat variable. Calls.
voeltzkowi (Mohéli): Twittering song similar to previous race. Calls.
nominate (Madagscar): Presumed song (?) fast trills interspersed by more nasal notes. Calls.
Despite the few recordings available for races moebii and voeltzkowi, there are strong indications that voice is quite different from nominate. There is, however, some confusion concerning what constitutes the song of the nominate. Hawkins et al. (2015) don’t describe the above trilled vocalization, but mention a rarely heard complex warbling phrase. Fast trills are also known in other sunbird species, and are not necessarily the true song. On the other hand, such a trill is seemingly unknown for moebii or voeltzkowi. It is thus probably that there are significant differences in ‘song-like vocalizations’. Calls of nominate are also lower-pitched over a narrower frequency range and different in shape.
More recordings are needed to acquire a better understanding of the vocal repertoire, but it would seem that the voice of the nominate is different from the other two races, with the latter two apparently being much more similar.
This note was finalized on 27th April 2016, using sound recordings available online at the time. I would like to thank in particular the sound recordists Bernard Bousquet, Fernand Deroussen, Johannes Fischer, Phil Gregory, Marc Herremans, Pierre Huguet, Frank Lambert, Dan Lane, Albert Lastukhin, Hans Matheve and Mike Nelson.
Hawkins, F., Safford, R. & Skerrett, A. (2015) Birds of Madagscar and the Indian Ocean Islands. Christopher Helm, London.
Huguet, P. & Chappuis, C. (2003) Bird Sounds of Madagascar, Mayotte, Comoros, Seychelles, Reunion and Mauritius. 4 CD-set. Société d’Études Ornithologiques de France, Paris.
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: on341_long-billed_green_sunbird.pdf