Ornithological Note 125
Section(s): Voice, Systematics
In the following we briefly analyze and compare voice of the different races of Pearly-vented Tody-tyrant (Hemitriccus margaritaceiventer). 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 is a short rising series of sharp staccato notes followed by a trill descending in pitch, “tick-tick-tr’r’r’r’r’r’r’r”. In some races full song is a gradual build-up of incomplete phrases till the full song phrase is given (and sometimes this sequence never gets to a full song with trill). There are many variant call series which may have a different function, e.g. phrases where the trill is replaced by an accelerating series of staccato notes etc.
We compare here exclusively a single 'full song phrase' among races.
H. m. impiger (H. m. septentrionalis no recordings, H. m. chiribiquetensis no recordings) Song build-up rarely reaches the full song with a descending trill, but there are at least a few examples (n=3)
intro notes
max. length 0.04-0.055s
min. av. freq. 2070-2700Hz
max. av. freq. 3100-3600Hz
trill
length 0.35-0.40s
max. av. freq. 3400-3500Hz
min. av. freq. 2200-2300Hz
# of notes 20-23
pace 0.017-0.0174
H. m. auyantepui (H. m. duidae no recordings, H. m. breweri no recordings) (n=5)
intro notes
max. length 0.04-0.07s
min. av. freq. 2200-3100Hz
max. av. freq. 3200-3600Hz
trill
length 0.29-0.50s
max. av. freq. 3300-3600Hz
min. av. freq. 2700-3200Hz
# of notes 11-20
pace 0.0235-0.0255
H. m. rufipes Song build-up rarely reaches the full song with a descending trill, but there is at least one example (n=2).
intro notes
max. length 0.045s
min. av. freq. 2600Hz
max. av. freq. 3500Hz
trill
length 0.5s
max. av. freq. 3400Hz
min. av. freq. 2600Hz
# of notes 18
pace 0.27
H. m. wuchereri, H. m. margaritaceiventer (n=10)
intro notes
max. length 0.04-0.055s
min. av. freq. 1960-2700Hz
max. av. freq. 3300-4200Hz
trill
length 0.18-0.39s
max. av. freq. 3100-4100Hz
min. av. freq. 2200-3100Hz
# of notes 8-18
pace 0.02-0.028
From the above measurements, it would seem that when comparing the homologous vocalization 'full song', there are hardly obvious differences among the 4 groups. The only apparent difference is that the (rarely heard) trill of impiger has slightly more notes and a faster pace. This is however based on just a few examples. If these are representative, then vocal score vs all other races would be: higher number of notes (score 1-2) and faster pace (score 1-2), but we need more recordings to be confident about this vocal difference.
All other races seemingly have no obvious differences in full song. Further detailed analysis may nevertheless discover some subtle differences in e.g. note shape, but this will not lead to a considerable vocal score according to Tobias criteria.
This note was finalized on 1st July 2015, using sound recordings available on-line at that moment. We would like to thank in particular the many sound recordists who placed their recordings for this species on XC and ML.
References
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: on125_pearly-vented_tody-tyrant.pdf
Recommended Citation
Boesman, P. (2016). Notes on the vocalizations of Pearly-vented Tody-tyrant (Hemitriccus margaritaceiventer). HBW Alive Ornithological Note 125. In: Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. https://doi.org/10.2173/bow-on.100125
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