Table 1.

Summary of the values and calculations used to generate the terms of Hamilton's rule, r, b and c, in long-tailed tits. Values in bold are those used in parametrizing Hamilton's rule.

term	marginal effect of helper on current brood productivity	marginal effect of helper on future productivity of male breeder	marginal effect of helping on helper's future productivity
r	relatedness of helper to brood, →rh−b = 0.16	relatedness of helper to helped male, →rh−m = 0.20	relatedness of helper to self, rh−h = 1
b	brood size = 8.9proportion of brood male = 0.53 Δ recruitment rate = +0.062	Δ survival rate = +0.05 probability of producing male recruit in year n + 1 = 0.26 →0.05 × 0.26 = +0.013 male recruits relatedness of breeder to recruits = 0.48	none
c	none	none	Δ survival rate = −0.23 probability of producing male recruit in year n + 1 = 0.26 →−0.23 × 0.26 = −0.0598 male recruits relatedness of helper to recruits = 0.48