Table 2.

Parameter estimates from the best-fit GLMM, which explained ARS as a function of individual alpha tenure, final year as an alpha, and linear and quadratic effects of individual age. (Individual identity was included as a random effect in this model, and data were 102 observations on 43 individuals. Bootstrapped 95% CIs for the fixed effects were generated by sampling 10 000 times with replacement to create datasets of 43 individuals' reproductive histories as alpha, including all sampled years for each selected individual. The electronic supplementary material, table S2 reports parameter estimates in the model excluding the final year term.)

model predictors	estimates ± s.e.	z	p	mean estimate from bootstrap	95% CI from bootstrap
					lower	upper
intercept	−5.51 ± 1.61	−3.43	0. 0006	−7.84	−13.83	−3.30
year of alpha tenure	0.51 ± 0.11	4.69	<0. 0001	0.62	0.33	1.08
age	1.22 ± 0.35	3.43	0.0006	1.72	0.75	3.02
age2	−0.07 ± 0.02	−3.48	0. 0005	−0.10	−0.18	−0.04
final year	−0.35 ± 0.19	−1.81	0.07	−0.39	−0.97	0.13