Table 1. Call type classification.

Type	Call name	No. of sections	Inter-pulsepeak interval (IPPI) pattern	Observed No. of pulses in section N
1	1	One
2	2	One	IPPIs converged at 13 ms
3	N9	One	Decreasing then increasing IPPI, median at 9 ms	29–30, 33–37
4	N10	One	Decreasing then increasing IPPI, median at 10 ms	27–29, 33–36, 43, 45, 51
5	N13	One	Nearly constant IPPI at 13 ms	3–7, 9, 11, 12, 14
6	N17	One	Increasing IPPI, median at 17 ms	3–15,18
7	iN13	One	Increasing, decreasing, then increasing IPPI, median at 13 ms	2–5, 9–17
8	iN15	One	Decreasing IPPI, median at 15 ms	7–11, 13, 15
9	1 + 1	Two	IPPI median at 41 ms
10	1 + N10	Two	Nearly constant IPPI, median at 10 ms	7–13, 15–25, 27, 28
11	1 + N12	Two	Nearly constant IPPI, median at 12 ms	13–26
12	1 + N19	Two	Increasing IPPI, median at 19 ms	2–8, 10, 11
13	2 + N9	Two	Near constant IPPI, median at 9 ms	23, 25, 27, 28, 30
14	2 + N10	Two	Near constant IPPI, median at 10 ms	19, 26, 27
15	2 + N18	Two	Increasing IPPI, median at 18 ms	3–8, 10
16	3 + N9	Two	Near constant IPPI, median at 9 ms	24–26, 29, 30
17	3 + N10	Two	Near constant IPPI, median at 10 ms	3–11, 24–25, 27–34, 37–39, 44
18	3 + N17	Two	Increasing IPPI, median at 17 ms	4–7
19	4 + N9	Two	Near constant IPPI, median at 9 ms	25–27, 31
20	4 + N10	Two	Near constant IPPI, median at 10 ms	3–7, 15, 25, 28, 30–31, 33, 35, 36
21	4 + N17	Two	Increasing IPPI, median at 17 ms	6
22	5 + N10	Two	Nearly constant IPPI, median at 10 ms	3–5, 7
23	(1 − )2 + N9	Three	Nearly constant IPPI, median at 9 ms	19, 22, 23
24	(1 − )2 + N10	Three	Nearly constant IPPI, median at 10 ms	2, 9–24, 29, 30
25	(1 − )2 + N12	Three	Nearly constant IPPI, median at 12 ms	6–11, 13–15, 19–21
26	1 + 2 + N10	Three	Nearly constant IPPI, median at 10 ms	16
27	1 + 2 + N18	Three	Nearly constant IPPI, median at 18 ms	5, 7
28	2 + 1 + N9	Three	Nearly constant IPPI, median at 9 ms	21, 23–25, 28, 29, 31, 32
29	2 + 1 + N10	Three	Nearly constant IPPI, median at 10 ms	23, 25–28, 30, 32, 34, 35, 40
30	(2 − )2 + N10	Three	Nearly constant IPPI, median at 10 ms	23, 26
31	3 + 1 + N9	Three	Nearly constant IPPI, median at 9 ms	23–25, 27, 30–32, 34
32	3 + 1 + N10	Three	Nearly constant IPPI, median at 10 ms	27–31, 33–35, 37
33	3 + 2 + N9	Three	Nearly constant IPPI, median at 9 ms	26
34	4 + 1 + N10	Three	Nearly constant IPPI, median at 10 ms	21, 29–31, 33
35	(1 − )3 + N9	Four	Nearly constant IPPI, median at 9 ms	18, 21, 26, 29
36	(1 − )3 + N10	Four	Nearly constant IPPI, median at 10 ms	1, 9–14, 16, 17, 19, 23–25, 27–29, 31, 33
37	(1 − )3 + N12	Four	Nearly constant IPPIs, median at 12 ms	8, 10, 13
38	(1 − )2 + 2 + N9	Four	Nearly constant IPPI, median at 9 ms	26, 29
39	(1 − )2 + 2 + N10	Four	Nearly constant IPPI, median at 10 ms	20, 21, 29
40	(1 − )2 + 3 + N10	Four	Nearly constant IPPI, median at 10 ms	18
41	2 + (1 − )2 + N9	Four	Nearly constant IPPI, median at 9 ms	22, 23
42	2 + (1 − )2 + N10	Four	Nearly constant IPPI, median at 10 ms	20–24, 26–33, 36
43	2 + 1 + 2 + N9	Four	Nearly constant IPPI, median at 9 ms	28
44	2 + 1 + 2 + N10	Four	Nearly constant IPPI, median at 10 ms	22, 25, 30
45	3 + (1 − )2 + N9	Four	Nearly constant IPPI, median at 9 ms	25
46	(1 − )4 + N9	Five	Nearly constant IPPI, median at 9 ms	15, 18, 23, 24
47	(1 − )4 + N10	Five	Nearly constant IPPI, median at 10 ms	1, 6, 7, 11, 13, 16–25, 27, 28
48	(1 − )4 + N12	Five	Nearly constant IPPI, median at 12 ms	11
49	(1 − )3 + 2 + N10	Five	Nearly constant IPPI, median at 10 ms	20, 21
50	(1 − )3 + 3 + N10	Five	Nearly constant IPPI, median at 10 ms	17
51	(1 − )2 + 2 + 1 + N10	Five	Nearly constant IPPI, median at 10 ms	26
52	(1 − )2 + 2 + 3 + N10	Five	Nearly constant IPPI, median at 10 ms	14
53	2 + (1 − )3 + N10	Five	Nearly constant IPPI, median at 10 ms	23–25, 27, 28, 32
54	(1 − )5 + N9	Six	Nearly constant IPPI, median at 9 ms	17, 21
55	(1 − )5 + N10	Six	Nearly constant IPPI, median at 10 ms	1, 16–23, 26
56	(1 − )4 + 2 + N10	Six	Nearly constant IPPI, median at 10 ms	15, 18–20, 28
57	(1 − )4 + 3 + N11	Six	Nearly constant IPPI, median at 11 ms	11
58	(1 − )3 + 2 + 1 + N10	Six	Nearly constant IPPI, median at 10 ms	16, 18
59	2 + (1 − )4 + N10	Six	Nearly constant IPPI, median at 10 ms	22
60	(1 − )6 + N10	Seven	Nearly constant IPPI, median at 10 ms	14–17, 19, 20, 24
61	(1 − )5 + 2 + N10	Seven	Nearly constant IPPI, median at 10 ms	16–18
62	(1 − )5 + 3 + N10	Seven	Nearly constant IPPI, median at 10 ms	16
63	(1 − )4 + 2 + 1 + N10	Seven	Nearly constant IPPI, median at 10 ms	16
64	(1 − )4 + (2 − )2 + N10	Seven	Nearly constant IPPI, median at 10 ms	20
65	(1 − )7 + N10	Eight	Nearly constant IPPI, median at 10 ms	11, 13, 14, 19, 21
66	(1 − )5 + (2 − )2 + N10	Eight	Nearly constant IPPI, median at 10 ms	9, 15

Notes.

For each signal, pulses with an inter-pulsepeak interval (IPPI) greater than 1.5 times the median IPPI of the signal were grouped into different sections. For signals that consisted of fewer than three pulses, pulses with an IPPI greater than 24 ms (three times the duration of a single pulse) were further grouped into different sections. In the call name column, ‘+’ is used to separate different sections of a call; the number denotes the number of pulses in that section; ‘(1 − )’ and ‘(2 − )’ denote repeated sections that consist of one and two pulses, respectively; the digital superscripts denote the number of repeats in the repeating section; ‘N’ denotes the last section of a call that varied in the number of pulses; the digital subscripts denote the median IPPIs of the last portion of the call; the subscript i denotes calls with a zero-to-peak sound pressure level of the first pulse approximately 10 dB weaker than that of the remainder within the call. For call types with more than one portion, the IPPI pattern of the last section is given.