In the following we briefly analyze and compare voice of the different races of Large Cuckoo-shrike (Coracina macei) and Javan Cuckoo-shrike (Coracina javensis). 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 Avian Vocalizations Center (AVoCet).
We have found only a few recordings of macei and a single (poor quality) one of race layardi. We compare here the commonly heard call of the different races (illustrated with many sonograms in the pdf version of this note):
macei (S India, Goa, Thana), macei ? (W Bengal,India)
layardi (Sri Lanka)
nipalensis (Assam, India)
siamensis (Myanmar, Thailand, Cambodia,Vietnam)
rexpineti (Taiwan)
larutensis (Peninsular Malaysia)
Rasmussen and Anderton (2012) state that macei/layardi has a longer call and lacks ending downturn. We can't confirm this, as illustrated in the above samples. We measured:
macei:
length 0.34 - 0.52s
max. freq. 4000- 5700Hz
other races (excl. rexpineti/larutensis)
length 0.30 - 0.44s
max. freq. 3000 - 3500Hz (with aberrant call from Vietnam reaching 3800Hz)
If we assume that layardi has similar voice as macei (as suggested by the single recording we have), then this group is clearly different from nipalensis/siamensis in reaching higher frequencies (score 2-3) and having a predominantly rising note shape (vs. fairly flat or up and down plateau in nipalensis/siamensis)(score 1). When applying Tobias criteria, this would lead to a total vocal score for macei/layardi vs. nipalensis/siamensis of 3-4.
rexpineti: it would seem that this vocalization is closer to Bar-bellied Cuckoo-shrike Coracina striata. (The description in Brazil (2009) confirms its double-noted call, ID is thus reliable). It is unclear whether rexpineti from mainland China also has a double call or not.
larutensis: call is clearly different from all other races: shorter and simpler, rather symmetrically overslurred.
length: 0.19 - 0.26s
max. freq.: 3500 - 3850Hz
Score vs. macei/layardi: length (2-3) and freq. (2) -> total score 4-5. Score vs. nipalensis/siamensis: length (2-3), freq. (1) and shape (1) -> total score 3-4.
If we compare larutensis with Javan Cuckooshrike (two recordings of javensis found):
length 0.31 - 0.45s
max. freq. 3200-3700Hz
It would seem that vocally javensis is closer to nipalensis/siamensis than to larutensis (!). larutensis is clearly different from both javensis and nipalensis/siamensis .
Conclusion:
* macei/layardi vs. nipalensis/siamensis are vocally moderately distinct: score 3-4.
* larutensis is different from all races, including C. javensis: score about 4 (this supports the suggestion by some that this taxon is a distinct species Malaysian Cuckoo-shrike)
* rexpineti from Taiwan has a voice more like C. striata, but voice from mainland China unknown.
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 AVoCet: Marc Anderson, Peter Boesman, David Edwards, David Farrow, Greg Irving, Frank Lambert, Ruey-Shing Lin, Martjan Lammertink, Andrew Mascarenhas, Sushant More, Mike Nelson, Ding Li Yong and Deepal Warakagoda.
References
Brazil, M. (2009). Field guide to the Birds of East Asia. Christopher Helm. London.
Rasmussen, P.C. & Anderton, J.C. (2012). Birds of South Asia: the Ripley Guide. Vols. 1–2. 2nd edition. National Museum of Natural History, Smithsonian Institution, Michigan State University & Lynx Edicions, Washington, D.C., Michigan & Barcelona.
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: on176_large_and_javan_cuckoo-shrike.pdf