In the following we briefly analyze and compare voice of the two races of White-throated Barbtail (Premnoplex tatei). 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).
Voice of P.t. pariae is a continuously repeated short rapid, almost rattled series of some 2-6 subdued mellow notes 'pu-dut...pu-du-du-dut...pu-du-dut...'. When excited, rarely gives even longer rattles of the same type of notes.
Voice of P.t.tatei is quite different, a continuously repeated double note (occasionally single or triple) usually with emphasis on the second and with rather a piping tone quality 'pee-peew!...pee-peew!..'.
Main sound parameters were measured with following results:
P.t. pariae (n=9)
max. frequency of all notes 2000-2620Hz
min. frequency of all notes 1000-1200Hz
max. note length in a sequence 0.03-0.05s
# of notes in a sequence 2 (22x), 3 (36x), 4 (19x), 5 (6x), 6 (1x) Av=3.14
space between notes 0.02-0.065s
max. frequency of all notes 2950-3400Hz
min. frequency of all notes 1000-1700Hz
max. note length in a sequence 0.10-0.11s
# of notes in a sequence 1 (10x), 2(43x), 3 (2x) Av=1.85
space between notes 0.06-0.09s
From the above measurements, we can conclude that P.t.tatei differs from P.t. pariae in reaching higher frequencies (score 2), delivering longer notes (score 3), typically in pairs rather than short series (score 1) and at a slower rate (score1). When applying Tobias criteria, this would lead to a total vocal score of 5.
This note was finalized on 16th April 2015, 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: Juan Areta, Nick Athanas, Peter Boesman and Hans Matheve.
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: on91_white-throated_barbtail.pdf