Vocal tract anatomy of king penguins: morphological traits of two-voiced sound production

Table 2 Measurements and statistical comparison of the two voices of male and female king penguin calls

Variable	Males (n = 42)	Females (n = 19)	P-value	DF	t-value
F0₁ [Hz]	423.2 ± 54.6	439.2 ± 41.7	0.217 n. s.	44.91	1.25
F0₂ [Hz]	463.5 ± 55.6	488.2 ± 45.9	0.07 n. s.	41.74	1.82
Frequency extent F0₂ [Hz] - F0₁ [Hz]	40.3 ± 11.5	49.0 ± 12.9	0.011	59.00	2.62
Period of Beats (1/ frequency extent) [s]	0.027 ± 0.007	0.022 ± 0.006	0.009	38.01	−2.76

Mean ± standard deviation and results of Welch’s t-tests comparing the first (F0₁) and the second voice (F0₂) between males and females. The extent did not follow a normal distribution and we thus performed a generalized linear model with a gamma transformation

ISSN: 1742-9994