Table 2. IM values and divergence times.

IM values and divergence time converted to years for t and TMRCA. Top rows are smoothed IM values and 95% credible intervals scaled to the neutral mutation rate of divergence time (t) between eastern and western samples in each species and the time to most recent common ancestor (TMRCA; divergence for clades). Bottom rows are IM values converted to time in years (T) assuming a generation time of one year and 2% sequence divergence per million years where the mutation rate (μ) is 1 × 10⁻⁸ substitutions/site/lineage/year and T = Lt/μ, where L, the length of the sequence in base pairs. Numbers in bold represent the biologically important divergence measure for each species in describing continent-wide divergence.

Species	t	95% low–high	TMRCA	95% low–high
Hermit Thrush	0.65	0.44–na*	11.79	8.26–17.12
	56,430	38,373–na*	1,031,601	722,240–1,498,023
Swainson’s Thrush	0.72	0.39–1.67	8.23	5.44–12.50
	65,841	35,384–152,733	752,002	496,810–1,142,934
Gray-cheeked Thrush	0.74	0.31–2.48	1.37	0.79–3.12
	65,092	27,017–216,833	119,528	68,714–273,123
Veery	0.34	0.08–2.30	0.73	0.34–2.51
	32,651	7,291–220,450	69,971	32,536–240,191
American Robin	0.19	0.09–3.30	1.31	0.62–3.25
	16,807	8,180–na*	114,304	54,514–284,296
Gray-cheeked Thrush and Veery	na	na	5.99	5.11–9.66
			572,967	489,234–924,641