In the following we briefly analyze and compare voice of the different races of Mangrove Vireo (Vireo pallens). 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).
Song of all races (for which recordings are available) is a repetition of a single note. Pace and number of repetitions is variable. The repeated note is usually burry or scratchy, but is also highly variable.
In the following we identify different 'note types' of the Caribbean mainland races, and try to look for equivalents in the Pacific populations (illustrated by sonograms in the pdf version of this note):
1. descending burry note "chew-chew-chew-chew..." ( 2 out of 10 recordings of Caribbean side)
2. slightly underslurred buzzy note ( 2 out of 10 recordings of Caribbean side)
3. Distinct V shape with burry end (4 out of 10 recordings)
4. Overslurred burry note
From the above, it is clear that many 'note types' from the Caribbean mainland have an equivalent in the population from S Mexico to Costa Rica. these notes are not necessarily identical, but given the variability and number of available samples, one can only say there is no obvious difference.
Voice of angulensis sometimes said to differ, e.g. HBW Alive (Brewer 2015) states: "in Bay Is (angulensis) a complex series of buzzes, chirps and warbles". From the 3 available recordings, we can't confirm this, as song is also a repeated single note, with a similar variability, albeit some note shapes are slightly different.
We don't have recordings of approximans, which is also said to differ.
Finally, race paluster of NW Mexico seems to have quite a few note types with peculiar shapes, apparently not shared with any other race.
As a conclusion, one could say that there is definitely not a clear vocal difference between birds from the Caribbean and birds from the Pacific. It would seem that the more remote populations (such as angulensis and paluster) have learnt notes which are more deviating.
This note was finalized on 20th October 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: Michael Anderson, Alfonso Auerbach, Mary Beth Sowe, Peter Boesman, Irby Davis, Steve Howell, Richard Hoyer, Orlando Jarquin, Jon King, Oliver Komer, Dan Lane, Mayron McKewy, Matthew Medler, Mike Nelson, Jelmer Poelstra, Mark Robbins, Andrew Spencer, Mario Trejo and John Van Dort.
Brewer, D. (2015). Mangrove Vireo (Vireo pallens). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/61243 on 20 October 2015).
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: on169_mangrove_vireo.pdf