Table 4.

Skylarks increased sound density by performing different syllable types in reactive song

	Spontaneous, mean ± SD	Reactive, mean ± SD	t	df	p	Adjusted p
Sound density (%)
Overall	74.51 ± 2.19	75.93 ± 1.62	4.51	15	0.0004	0.002
Most frequent syllable type	65.08 ± 8.44	65.53 ± 9.97	0.4596	15	0.65	0.65
Shared syllable types	75.81 ± 1.97	76.20 ± 2.89	0.6868	15	0.50	0.65
Unshared syllable types	75.73 ± 1.84	77.01 ± 1.57	2.8041	15	0.01	0.03

Sound density in overall sample and for subsets of most frequent, shared, and unshared song types in spontaneous and reactive song of skylarks (N = 16). Data were analyzed by paired t test. Significant p values are given in italics