In the following we briefly analyze and compare voice of the different races of Little Spiderhunter (Arachnothera longirostra). 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 Avian Vocalizations Center (AVoCet).
Our main interest is to compare Philippine races with the other taxa. Song in general of all races is quite variable, but typically consists of a rather fast repetition of a single or double note. We have only located a few recordings from the Philippines (illustrated with sonograms in the pdf version of this note): flammifera (and randi?), dilutior (no recordings of song available), and other races.
Based on four recordings of flammifera, song seems to be higher-pitched (max. frequency 6.2 - 7.2kHz vs all 'other races' 4.1 - 5.5kHz)(score 2-3). Other sound parameters similar based on these few recordings. Total vocal score thus about 2-3.
This note was finalized on 16th August 2016, using sound recordings available on-line at that moment. We would like to thank the many sound recordists who placed their recordings for this species on XC, Avocet and IBC, in particular Desmond Allen, Ross Gallardy and Pamela Rasmussen for recordings from the Philippines.
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: on431_little_spiderhunter.pdf