Table 1.

Sample sizes included for the CART and Levenshtein similarity index/Dice's similarity index analysis, and the length of recording and number of song cycles analysed per individual singer (note: individual singer numbers are arbitrary; e.g. individual 1 in 2001 Gabon is not the same individual 1 in 2003 Gabon).

	year	individual	length of recording	no. of song cycles
Gabon (BSB)	2001	1	2 h 2 min	7
		2	1 h 2 min	8
	2002	1	1 h 15 min	8
	2003	1	30 min	5
		3	22 min	1
		4	48 min	4
		6	51 min	3
	2004	1	26 min	1
		3	24 min	1
		5	52 min	3
	2005	2	1 h 31 min	5
		3	1 h 58 min	5
		7	21 min	3
		8	24 min	1
Madagascar (BSC)	2001	2	1 h 38 min	15
		3	56 min	16
	2002	1	2 h 1 min	7
		2	2 h 1 min	6
		8	50 min	3
	2003	6	1 h	2
		9	40 min	5
		10	46 min	7
		13	24 min	2
	2004	1	1 h 53 min	6
		8	1 h 49 min	5
		9	2 h 7 min	7
		11	1 h 37 min	6
	2005	10	48 min	4
		15	1 h 5 min	5
		18	2 h 1 min	6
		19	2 h 30 min	6