In the following we briefly analyze and compare voice of the different races of Sierran Elaenia (Elaenia pallatangae). 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).
Members of the genus Elaenia have a dawn song and several day-time 'calls'. Dawn song is usually the most complex vocalization, often quite rhythmic, and very constant over the entire range of the species (a true suboscine!). Unlike some other Tyrant-flycatchers (e.g. Zimmerius genus), every species has a very characteristic dawn-song, which thus is an excellent indicator for taxonomic decisions. It is only in recent years that gradually with increasing knowledge more dawn songs of Tyrant flycatchers have been gathered. Obviously, the issue is that birds sing in near-darkness, and identification of the 'singing silhouette' is problematic, while singing may be limited to a short period in the year.
Andean Birds (E. p. pallatangae, intensa, exsul)
Dawn song can be transcribed as "chrewee...chrewee...chrewee-krrr...chrewee..." . This can be heard in Ecuador, Peru and Bolivia. (max. freq. 4100-4300Hz, min. freq. 800Hz).
Calls include a short whit! (0.29s length,4500- 4620max. freq.), a more burry "wheer!" (0.20s, 3900-4300Hz max.), a mellower downslurred "wheer-up" (0.37s, 4700Hz max.)
Tepuis (SE Venezuela and Guyana) (olivina)
A song-like vocalization recorded during the day (day song?)(ML145333) has irregular sharp notes "chi-tree-trew...tree-trew...chip..." (max. freq. 5300Hz, min. freq. 2400Hz).
Mostly recorded call is a short sharp "pseeuw!" or a more burry "prreeuw!" (length 0.16-0.27s, max. freq. 5000-7700Hz). Also a mellower descending "pieuw" (0.28s, 5200Hz max.)
Unfortunately there is no certainty about the dawn-song of olivina, for which we can't really compare this primary vocalization.
In general one can say that most if not all vocalizations clearly reach a higher frequency in olivina (score 3). There is no second sound parameter which is clearly different. When applying Tobias criteria, this would lead to a total vocal score of 3, with the important remark that comparison of dawn songs was not possible.
This note was finalized on 25th June 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: Roger Ahlman, Israel Aragon, David Ascanio, Nick Athanas, Peter Boesman, Paul Coopmans, David Geale, Bennett Hennessey, Jonas Nilsson, Niels Krabbe, Gabriel Leite, Hans Matheve, Sjoerd Mayer, Ted Parker, Mark Robbins, Scott Olmstead, Andrew Spencer and Marcelo Vilegas.
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: on133_sierran_elaenia.pdf