Table 1. Summary of results of two-choice-trials between song models differing in CF, in relation to the mean threshold difference of the AN1-neuron for the two involved frequencies, established in each individual female (preferred CF in bold; “z-test”).

Choice for alternative Frequency [kHz]	Intensity difference [dB]	Significance (N)
3.5 versus 5	32.6	P<0.001 (17)
3.5 versus 5.5	27.7	P<0.001 (13)
3.5 versus 4.5	26.2	P<0.001 (18)
4 versus 5	23.5	P<0.001 (39)
5.5 versus 4	18.6	P<0.001 (32)
4 versus 4.5	17.1	P<0.001 (40)
6 versus 4	15.2	P<0.001 (12)
3.5 versus 4	9	P<0.001 (15)
6 versus 5	8.3	P<0.001 (18)
4.5 versus 5	6.4	P<0.001 (40)
5.5 versus 5	4.9	P = 0.049 (33)
6 versus 5.5	3.4	P = 0.705 ns (14)
6 versus 4.5	1.9	P = 0.317 ns (18)
5.5 verus 4.5	1.5	P = 1.000 ns (33)
4.8 versus 5	0.7	P = 0.808 ns (34)

Note that in all cases in which the difference in sensitivity was higher than 3.4 dB, there was a significant preference for the more sensitive frequency.