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. Author manuscript; available in PMC: 2010 Jan 1.
Published in final edited form as: Horm Behav. 2008 Nov 1;55(1):217–227. doi: 10.1016/j.yhbeh.2008.10.006

Table 2.

Spectral Properties, Warble and Whistle

Time Statistics

Day 6 (n = 9) Day 8 (n = 10) Day 10 (n = 9) Day 21 (n = 9) ANOVA

Whistle pitch (kHz)
Mean 3.34 ± 0.09 3.44 ± 0.15 3.42 ± 0.11 3.41 ± 0.11 F3,9 = 1.22, P = 0.325
CV 0.11 ± 0.03a 0.06 ± 0.02a,b 0.04 ± 0.01a,b 0.03 ± 0.01b F3,9 = 4.66, P = 0.011

Whistle FM (degrees)
Mean 6.94 ± 0.40a 5.65 ± 0.57a,b 4.51 ± 0.47b,c 3.75 ± 0.39c F3,9 = 7.69, P < 0.001
CV 0.50 ± 0.08 0.41 ± 0.08 0.40 ± 0.08 0.32 ± 0.06 F3,9 = 1.24, P = 0.318

Whistle entropy
Mean −5.68 ± 0.13a −5.66 ± 0.12a −5.82 ± 0.12a,b −6.09± 0.05b F3,9 = 5.49, P = 0.005
CV −0.06 ± 0.01a −0.06 ± 0.02a −0.04 ± 0.01a,b −0.01± 0.01b F3,9 = 4.65, P = 0.011

Whistle pitch goodness
Mean 34.57± 4.41a 34.19± 5.28a 28.20 ± 4.35a,b 17.34±1.71b F3,9 = 8.11, P < 0.001
CV 0.18 ± 0.04 0.09 ± 0.02 0.11 ± 0.02 0.07 ± 0.02 F3,9 = 4.81, P = 0.010

Warble pitch (kHz)
Mean 3.56 ± 0.14a 3.78 ± 0.11a,b 3.74 ± 0.11a,b 3.90 ± 0.09b F3,9 = 4.41, P = 0.014
CV 0.11 ± 0.04 0.06 ± 0.02 0.05 ± 0.01 0.03 ± 0.00 F3,9 = 2.12, P = 0.126

Warble FM (degrees)
Mean 25.67± 2.12a 22.17 ± 2.06b 22.16 ± 2.28b 20.89±3.49b F3,9 = 5.48, P = 0.005
CV 0.28 ± 0.06a 0.16 ± 0.03a,b 0.14 ± 0.02b 0.10 ± 0.02b F3,9 = 5.12, P = 0.007

Warble entropy
Mean −5.05 ± 0.15a −5.28 ± 0.09a,b −5.27 ± 0.13a,b −5.56± 0.12b F3,9 = 5.42, P = 0.006
CV −0.08 ± 0.02a −0.04 ± 0.01a,b −0.03 ± 0.01a,b −0.02± 0.01b F3,9 = 3.34, P = 0.037

Warble pitch goodness
Mean 80.87± 8.78a 68.39 ± 6.32a,b 69.58 ± 7.89a,b 58.88±10.82b F3,9 = 4.60, P = 0.012
CV 0.26 ± 0.05a 0.14 ± 0.02b 0.15 ± 0.02a,b 0.13±0.01a,b F3,9 = 3.94, P = 0.021

All values are mean ± SEM. CV = Coefficient of Variation (SD/mean). FM = frequency modulation. Entropy and pitch goodness are unitless. Different superscript letters denote significant differences across a row. Across a row, groups with the same letter do not significantly differ from one another. Lack of letters indicates that no significant differences were found.