Costs of growing up as a subordinate sibling are passed to the next generation in blue-footed boobies

As stresses in early development may generate costs in adult life, sibling competition and conflict in infancy are expected to diminish the reproductive value of surviving low-status members of broods and litters. We analysed delayed costs to blue-footed booby fledglings, Sula nebouxii, of junior status in the brood, which involves aggressive subordination, food deprivation and elevated corticosterone, but little or no deficit in size at fledging. In ten cohorts observed for up to 16 years, juniors showed no deficit in breeding success at any age, independent of lifespan, including in a sample of sibling pairs. Among females, juniors actually outreproduced seniors across the 16-year span. However, offspring produced by juniors in the first 3 years of life were less likely to recruit into the breeding population than offspring of seniors. Since junior fledglings survive, recruit and compete as well as seniors (shown earlier), and breed as successfully as seniors across the lifespan, it a...