Ornithological Note 179
In the following we briefly analyze and compare voice of the two races of Golden Cuckoo-shrike (Campochaera sloetii). 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 both races is structurally similar, a series of short stuttered notes followed by or interspersed with one or more melodious whistles.
Some examples (illustrated by sonograms in the pdf version of this note): sloetii (Northern region) and​ flaviceps (Southern region)
There seem to be slight differences in voice between both races: loetii has less upslurred whistles, and if present, these never are as rising as in flaviceps (score 1). Shape of the short stuttered notes is also slightly different, more variable in sloetii with 'bend in shape' not as clear-cut as in flaviceps (see arrows) clearly audible as different sounding (score 1). Using Tobias criteria as a guidance, this would lead to a total vocal score of about 2.
This note was finalized on 4th November 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: Scott Connop, Frank Lambert, Hans Matheve, John V Moore and Bas Van Balen.
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: on179_golden_cuckoo-shrike.pdf