Table 2.

Song attributes

Attribute	Early spring	Late spring	Early fall	Late fall
Repertoire size (number of song types)	7.60 ± 0.75^2-a	7.60 ± 0.75	7.40 ± 0.68	7.60 ± 0.81
Song type complexity (MUPs/song)	7.00 ± 0.56	6.60 ± 0.45	6.80 ± 0.60	6.86 ± 0.77
Trill length (syllables/trill)^*	4.45 ± 0.27^b	4.62 ± 0.35^b	3.81 ± 0.11^c	3.88 ± 0.11^c
Rate of song type variation (variations/rendition)^*	0.61 ± 0.06^b,^c	0.50 ± 0.06^b	0.68 ± 0.06^c	0.69 ± 0.06^c
Variation similarity score (within song type)	0.58 ± 0.03	0.61 ± 0.03	0.56 ± 0.01	0.57 ± 0.03
Syllable cross-correlation^*	0.85 ± 0.02^b	0.85 ± 0.01^b	0.78 ± 0.01^c	0.76 ± 0.02^c

↵F2-a Values are mean ± SEM.
^b,^c Values in same row with different superscripts differ significantly from each other, PLSD,p < 0.05.
↵* One-factor repeated measures ANOVA, p < 0.05;n = 5 for all measures.