Notes on the vocalizations of Yellowish Flycatcher (Empidonax flavescens)

In the following we briefly analyze and compare voice of the three races of Yellowish Flycatcher (Empidonax flavescens). 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).

Vocabulary of this species is seemingly quite limited: besides a typical Empidonax dawn song, there are 2 commonly heard day-time notes (which could be considered day-time 'song' and 'call'). We have only found 1 recording on-line of dawn song from Costa Rica (flavescens). In the following, we therefore focus on the two other vocalizations.

1. rising note "pseeet!"

E. f. salvini  (n=7)

min. freq.                              3250-4400Hz

max. freq.                             6200-6650Hz

length                                    0.31-0.38s

E. f. imperturbatus (n=1)

min. freq.                              3840Hz

max. freq.                             6080Hz

length                                    0.30s

E. f. flavescens (n=6)
min. freq.                              2200-4000Hz

max. freq.                             6120-6700Hz

length                                    0.25-0.33s

2.  short high-pitched underslurred note "psit"

E. f. salvini  (n=2)

min. freq.                              6200-6500Hz

max. freq.                             7600-7780Hz

length                                    0.11-0.15s

E. f. imperturbatus (n=0)

E. f. flavescens (n=3)
min. freq.                              6010-6800Hz

max. freq.                             7460-8600Hz

length                                    0.11-0.15s

 

It is clear from the above that both vocalizations are very similar among races. The rising note "pseet!" may be marginally shorter in flavescens, but this may be a consequence of being better quality recordings where the end of the note is more clear-cut on the sonogram. In the absence of dawn songs from northern populations, there is thus no evidence of any clear difference in voice among taxa.

 

This note was finalized on 10th July 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: Peter Boesman, Kathi Borgmann, Paul Driver, Jesse Fagan, Guillermo Funes, Steve Howell, Samuel Jones, Jon King, Frank Lambert, Matthew Medler, Mike Nelson, Scott Olmstead, Ted Parker, Mark Robbins, David Ross, John Van Dort and Charlie Vogt.

 

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: on147_yellowish_flycatcher.pdf