Age-related parental care in a long-lived bird: implications for offspring development

摘要

In long-lived species, behaviour is expected to vary across the lifespan, first improving with maturation and experience and then declining with senescence, but measurement is rare, particularly during old age. Measuring nest defence intensity in 255 known-age blue-footed boobies (Sula nebouxii) of 19 age classes confirmed the inverted-U pattern: intensity of nest defence increased in young males and females until roughly 1112 years and declined progressively afterwards. We discuss the processes that may generate this distinctive pattern. Regardless of the underlying processes, this study establishes the existence of age-related variation in parental care in a long-lived species. Natural variation in natal conditions has recently been shown to have long-termimpacts on development, so this study raises the question whether age-related changes in parental care generate systematic variation in offspring phenotypes.