In the following we briefly analyze and compare voice of the races of Yellow-throated Warbler (Dendroica dominica). 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).
Our main interest is to compare song of the race flavescens from the Bahamas with the mainland race. There are only a few sound recordings available of the song of flavescens (illustrated with sonograms in the pdf version of this Note). The difference in song is quite clear from the sonograms, with flavescens having a song starting at stable pace and with a narrow frequency range, and ending with notes somewhat louder, higher-pitched and having a wider frequency range. Birds of the mainland have a song with notes covering a much wider frequency range, starting at much higher frequency, and showing a downward trend in pitch.
A quantified analysis was recently made by McKay et al. (2010) (Table reproduced in the pdf version of this Note). Based on these data we get following scores:
Highest freq. of song: flavescens significantly lower (Effect size 3.05, score 2). Freq. change (start/end): flavescens has much smaller pitch change (Effect size 2.62, score 2). Max. freq. of first note: flavescens much lower (Effect size 6.12, score 3).
Furthermore, from the sonograms, it is also clear that freq. range of both the total phrase and single notes is much smaller in flavescens. Application of Tobias criteria leads to a total vocal score of 5.
This note was finalized on 27th June 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 and ML, in particular Jesse Fagan, Jim Holmes and Linda Macaulay for recordings of flavescens.
McKay, B.D., Reynolds, M.B.J., Hayes, W.K. & Lee, D.S. (2010). Evidence for the species status of the Bahama Yellow-throated Warbler (Dendroica “dominica” flavescens). Auk 127(4): 932–939.
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: on374_yellow-throated_warbler.pdf