Table 2 

Description of acoustic parameters used in the analysis 

Parameter Number 
Parameter description 


1 
Duration of the entire call [s]: from the starting point of the first element till the ending point of the last element 
2 
Elements: amount of elements (inhalation and exhalation) 
3 
Elements per second [e/s]: amount of elements over the duration 
4 
Maximum frequency start [Hz]: maximum frequency of the starting points of the entire elements 
5 
Minimum frequency start [Hz]: maximum frequency of the entire starting points of elements 
6 
Maximum frequency end [Hz]: maximum frequency of the entire ending points of elements 
7 
Minimum frequency end [Hz]: minimum frequency of the entire ending points of elements 
8 
Mean frequency start [Hz]: arithmetic mean of the frequency of the entire starting points of elements 
9 
Mean frequency end [Hz]: arithmetic mean of the frequency of the entire ending points of elements 
10 
Exhalation elements: amount of exhalation elements 
11 
Inhalation elements: amount of inhalation elements 
1215 
1^{st }, 2^{nd}, 3^{rd } and 4^{th } quarter elements per second [e/s]: amount of elements over the duration of respective quarters 
16 
Middle part elements per second [e/s]: amount of elements over the duration of the 2^{nd }and 3^{rd }quarter 
1720 
1^{st }, 2^{nd}, 3^{rd } and 4^{th } quarter mean frequency start [Hz]: arithmetic mean of the frequency of the entire starting points of elements of respective quarters 
21 
Middle part mean frequency start [e/s]: arithmetic mean of the frequency of the entire starting points of elements of the 2^{nd }and 3^{rd }quarter 
2223 
1^{st }, and 2^{nd } quarter mean frequency end [Hz]: arithmetic mean of the frequency of the entire ending points of elements of respective quarters 


Meyer et al. BMC Evolutionary Biology 2012 12:16 doi:10.1186/147121481216 