Notes on the vocalizations of Marcapata Spinetail (Cranioleuca marcapatae)

In the following we briefly analyze and compare voice of the two races of Marcapata Spinetail (Cranioleuca marcapatae). 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).

Song of both races is quite different:

weskei (n=7): Song is a short tinkling rattle of typically 7-9 descending overslurred notes, and usually ending with 1-3 more scratchy notes.

Measurements:

# of notes                                              8-12

total length                                            0.5-0.84s

pace*                                                     0.058-0.07s

max. freq.                                              5000-6500Hz

note with highest freq.                         1

note shape                                             mostly round overslurred (sounding sweet tinkling)

* Pace here expressed as period, average duration of note + pause

marcapatae (n=9): Song is much more variable than weskei, typically a loose series of rising/falling notes, often in longer sequences with alternating high-pitched and lower-pitched notes (presumably duets), and often ending with a short series of gravelly notes.

Measurements:

# of notes                                              10-30

total length                                            1.0-3.4s

pace                                                       0.11-0.14s

max. freq.                                              7400-9400Hz

note with highest freq.                         any place in the series, but basically never the first note

note shape                                             mostly spiky irregular shapes (sounding sharp and piercing)

Conclusion

Song of weskei differs from marcapatae by much more uniform delivery, shorter length (score=2), lower max. frequency (score=2), faster pace (score=2 or 3), descending song strophe (vs. rising and falling, score 2) and different note shape (score 1). This would lead to a total vocal score of 4 or 5 when applying Tobias criteria.

This note was finalized on 28th 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: Peter Boesman, Gunnar Engblom, David Geale, Andrew Spencer, Fabrice Schmitt and Herman Van Oosten.

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: on100_marcapata_spinetail.pdf