Table 1.

Comparisons of controls versus isolates

		Day 65	Day 91	Day 120	Day 150	Day 180
Estimated total neurons in HVC (SEM)	Controls	26,277 (1,246)	40,406 (3,545)	47,798 (1,910)	37,080 (4,135)	40,911 (1,821)
	Isolates	27,140 (3,421)	40,437 (1,826)	41,207 (2,979)	39,111(3,318)	*56,336 (3,448)
Amount of singing, bouts per hour (SEM)	Controls			107 (12), n = 6	74 (9), n = 5
	Isolates			86 (8), n = 6	75 (14), n = 5
Testosterone, ng/ml (SEM)	Controls			0.25 (0.10), n = 6	0.68 (0.37), n = 5	0.16 (0.16), n = 4
	Isolates			0.37 (0.12), n = 16	0.44 (0.15), n = 5	0.79 (0.33), n = 6
Syllable similarity over 3 weeks (SEM)	Controls			77.2 (1.2), n = 5	80.1 (0.6), n = 5
	Isolates			*53.0 (2.3), n = 5	*60.2 (3.4), n = 5
Syllable similarity on same day (SEM)	Controls			80.3 (1.6), n = 5	82.2 (0.9), n = 5
	Isolates			*65.6 (5.5), n = 5	*68.8 (3.0), n = 5
Change in same-day similarity over 3 weeks (SEM)	Controls			0.66 (1.38), n = 5	0.56 (1.01), n = 5
	Isolates			3.00 (3.29), n = 5	1.67 (2.83), n = 5
Minimum number of motif sequences in 80% of song (SEM)	Controls			2.6 (0.5), n = 6	2.2 (0.4), n = 5	2.7 (0.9), n = 5
	Isolates			*11.7 (3.9), n = 6	*20.0 (7.3), n = 5	8.2 (3.9), n = 6

Note: Lower song similarity scores indicate higher song variability.

*p < 0.05, isolates versus controls.