In the following we briefly analyze and compare voice of the different races of Cliff Flycatcher (Hirundinea ferruginea). 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 all races is structurally very similar, a long note followed by a trilled series of notes (which highly vary in number).
There are however some notable differences:
NW group: H. f. sclateri and H. f. ferruginea (n=9)
Length 1st note 0.15-0.21s
min. note length 0.03-0.05s
max. freq. 2600-3100Hz
freq. range* 1100-1400Hz
max. pace** 0.05-0.088
* freq. range of fundamental
** pace is measured as period, duration between two subsequent notes
SE group: H. f. pallidior and H. f. bellicosa (n=9)
Length 1st note 0.20-0.37s pallidior and 0.28-0.40s bellicosa
min. note length 0.033-0.040s
max. freq. 1810-2400Hz
freq. range 600-1000Hz
max. pace 0.041-0.055
Also: in about all samples of SE group the first long note seems to be connected to the first note of the trill, while in the NW group, there is a very clear separation between first long note and subsequent notes.
Differences are thus: Song of pallidior/bellicosa is lower-pitched (score 2-3), has a smaller frequency range (score 2), reaches a faster pace (score 1-2) and has a longer start note (score 1-2). When applying Tobias criteria we obtain as a total vocal score about 4.
This note was finalized on 3rd July 2015, using sound recordings available on-line at that moment. We would like to thank in particular the many sound recordists who placed their recordings for this species on XC and ML.
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: on126_cliff_flycatcher.pdf