In the following we briefly analyze and compare voice of the three races of Spot-crowned Woodcreeper (Lepidocolaptes affinis). 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), Macaulay Library (ML).
1. Comparison of song of the three races (illustrated with sonograms in the pdf version of this note): lignicida, affinis (Mexico, Honduras and El Salvador), neglectus (Costa Rica, Panama).
Difference in song between neglectus and the two northern races is striking (the very constant characteristics of the 2 northern races over their entire range makes the sudden change even more remarkable). Song of affinis (with lignicida) is typically a long underslurred note followed by one or two shorter underslurred notes. The first note can be rather nasal, the subsequent ones typically well above 5kHz. Song of neglectus is a long overslurred nasal note, followed by a fast trill of some 20-30 notes, going slightly up and down in pitch.
affinis/lignicida neglectus score
# of notes 2 - 4 19 - 30 4
total length 1.2 - 2s 1.9 - 3.2s 2-3
length shortest note 0.23 - 0.38s c 0.05-0.07s 3-4
max. freq. c 8.2 - 9kHz 3.0 - 3.3kHz 3
note shape underslurred overslurred 1-2
When excited (e.g. after playback), affinis may also give a faster series of notes (as in many other Woodcreeper species), but this is not the normal song, and thus should not be considered in the above comparison between homologous vocalizations.
2. Comparison of call notes
Call notes are very similar to the first note of the song, thus a single underslurred note in affinis vs an overslurred note in neglectus. Besides the different note shape, measurable differences are e.g. maximum frequency of base harmonic, which is much lower in neglectus.
We can thus conclude that the vocalisations of the two groups are clearly very different. Application of Tobias criteria would lead to a total vocal score of about 7.
As a final remark, we can observe that song of neglectus is somewhat closer to Montane Woodcreeper L. lacrymiger, but still readily identifiable.
This note was finalized on 24th May 2016, 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: Ken Allaire, Peter Boesman, Sander Bot, Oscar Campbell, Allen Chartier, Samuel Jones, Dan Lane, Richard Garrigues, Oscar Marin Gomez, Richard Hoyer, Jon King, Mayron McKewy Mejia, Mike Nelson, Mark Robbins, David Ross, Roberto Sosa, Andrew Spencer and Walter Thurber.
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: on418_spot-crowned_woodcreeper.pdf