Notes on the vocalizations of Tawny Antpitta (Grallaria quitensis)

In the following we briefly analyze and compare voice of the different races of Tawny Antpitta (Grallaria quitensis). 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).

There are only a few recordings available for the races other than quitensis. Based on these, it appears that loudsong of the 3 races is quite different (Fig. 1):

quitensis         3 evenly spaced notes 'tip..tuu..tuu'

atuensis          3 notes, last note after shorter pause bisyllabic and rising 'tip..tuu.tuee'

alticola            4 notes, last 3 notes in rhythmic sequence 'tip..pur.whe-tuu'

 

We have made some measurements for some basic sound parameters, with following results:

                                               quitensis         atuensis              alticola

                                                (n=8)                     (n=3)                 (n=1)

# notes                                  3                             3                             4

min. pause                            0.26-0.35s            0.18-0.24s            0.05s

max. note length                 0.17-0.23s            0.32-0.34s            0.25s

min note length                   0.10-0.16s            0.14-0.2s               0.11s

max. freq.                             1960-2200Hz       2400Hz                  1980Hz

min. mid freq.                      1800-1900Hz       2050-2100Hz       1500Hz

 

Assuming a larger sample size confirms these data, scoring would give:

atuensis differs from quitensis by long and rising end note (score 2) and higher pitch (score 1). Total score 3.

alticola differs from quitensis by a 4 note song with short pauses between last 3 notes (score 4) resulting in a rhythmic phrase, and also by reaching lower frequencies (score 1). Total score 5.    

As the most common call note also seems to differ between the 3 races (Fig. 2), with especially atuensis very different, we have made also here some measurements:

quitensis (n=5)

total length                           0.21-0.24s

min. freq.                              850-1200Hz

max. freq.                             4400-5200Hz

freq. range                           3600-4050Hz

note shape                           a modulated start followed by a downslurred whistle

 

atuensis (n=2)

total length                           0.63-0.64s

min. freq.                              1800Hz

max. freq.                             3450Hz

freq. range                           1650Hz

note shape                           a long very burry start followed by an underslurred whistle 

 

alticola (n=3)

total length                           0.31-0.32s

min. freq.                              1800-2300Hz

max. freq.                             2200-3300Hz

freq. range                           400-1000Hz

note shape                           a smooth downslurred whistle

 

Main differences of atuensis vs. quitensis: atuensis has longer note length (score 3), smaller frequency range (score 2-3) and lower max. frequency (score 1-2), and a very distinct note shape. -> total score 5-6

Main differences of atuensis vs. alticola: atuensis has longer note length (score 3), higher frequency range (score 2), and a very distinct note shape -> total score 5

 

We can thus conclude that there are major vocal differences between all three races, both in loudsong and call note.

 

This note was finalized on 13th 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: Roger Ahlman, Nick Athanas, Peter Boesman, Allen Chartier, Oswaldo Cortes, Niels Krabbe, Dan Lane, Bernabe Lopez-Lanus, John V. Moore, Leonardo Ordoñez, Bob Planqué, Jeisson Poveda, Andrew Spencer, Mark Todd and Willem-Pier Vellinga.

 

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: on72_tawny_antpitta.pdf