Notes on the vocalizations of Streaked Flycatcher (Myiodynastes maculatus)

In the following we briefly analyze and compare voice of the different races of xxxx. 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).

1. Dawn song

With respect to dawn song, there are two groups which clearly differ. We have examined all available dawn-songs to see which taxa belong to which group.

Group 1: dawn song with high-pitched rising end note: Dawn song is remarkably similar over its entire range: a first upslurred note which starts at fairly high frequency, a high-pitched overslurred note, a low-pitched underslurred note, a high-pitched down-slurred note and a rising note with bend at high pitch. 

The following races have this dawn song type:

M. m. insolens no recordings

M. m. difficilis  3 recordings from Panama and W Venezuela

M. m. nobilis 1 recording presumably of this taxon from Santander, Colombia.

M. m. tobagensis 2 recordings from Bolivar, Venezuela and Guyana

M. m. chapmani 5 recordings from W Ecuador and NW Peru

M. m. maculatus no recordings

Measurements:

total length                                          0.67-0.85s

min.freq. first note                             1300-2300Hz (typically around 1900Hz)

bend freq. last note                           3100-3700Hz

Group 2: dawn song with low-pitched end note: Dawn song over its entire range is a first upslurred note which starts at fairly low frequency, a short low-pitched overslurred note, a long high-pitched overslurred note, a high-pitched down-slurred note and a rising note with bend at low pitch. 

The following races have this dawn song type:

M. m. solitarius 12 recordings from SE Peru, Argentina, Bolivia and Brazil

1 recording from eastern foothills of C Peru presumably this taxon (or maculatus??)

Measurements:

total length                                          0.48-0.58s

min.freq. first note                             780-1140Hz

bend freq. last note                           1450-2050Hz

In comparison with group 1, it is clear that the total song phrase is signficantly shorter (score 2-3), that there are several frequency related differences such as min.freq. first note and bend freq. last note (score 3). The overall pattern of the 5 notes is also quite different, with e.g. note 2 and 3 very different (score 2). When appling Tobias criteria this would lead to a total vocal score of about 5.

 2. Day-time call

The commonest vocalization given during the day is a repeated emphatic short note. At closer examination, it is clear that there are again 2 vocal groups: one groups has a nasal note which is nicely overslurred "kuk", the other group has a less nasal note which is clearly upslurred "quit".

Group 1: overslurred day-time call

The following races have this dawn song type:

M. m. insolens 3 recordings (sometimes with an additional long note, not seen in other races)

M. m. difficilis 6 recordings from Panama, Colombia and W Venezuela

M. m. nobilis 2 recordings

M. m. tobagensis 8 recordings from Venezuela

M. m. chapmani 8 recordings from W Ecuador and NW Peru

M. m. maculatus 3 recordings from Boa Vista, Manaus in Brazil, (and Loreto, Peru also this taxon?)

Measurements:

total length                           0.05-0.07s                           

min.freq.                               700-940Hz           

max. freq.                             1600-1940Hz

freq. range                           800-1150Hz        

Group 2: upslurred day-time call

The following races have this dawn song type:

M. m. solitarius 10 recordings from SE Peru, Argentina, Bolivia and Brazil

1 recording from eastern foothills of C Peru presumably this taxon

Measurements:

total length                           0.04-0.057s         

min.freq.                               800-1300Hz

max. freq.                             3000-3500Hz

freq.range                            1900-2400Hz

Interestingly the dividing line between the 2 vocal groups is again solitarius versus all other races !

Differences in day-time call can be quantified as follows: freq. range and max. freq. of solitarius is much higher than the other group (score 3-4), with different note shape (score 1-2). Total score vocal score about 5.

All together, the vocal difference of solitarius versus all other races is quite remarkable. If we would take the two highest scores out of the 2 vocalizations examined, this would give a score of at least 6.

 

This note was finalized on 20th August 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.

 

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: on142_streaked_flycatcher.pdf