Theory suggests that a male strategy of reducing parental care in response to reduced parentage should evolve only under certain conditions. Expected paternity in subsequent matings is predicted to be primary in effect, because it determines whether there is a future benefit to compensate males for the cost of reduced care. This study, tested whether provisioning of nestlings by socially monogamous male yellow warblers,Dendroica petechia, varied with the males' parentage in the brood and how males' paternity varied in subsequent matings. Analysis included observations of parental care from 40 nests (31 of which had paternity determined by multi-locus DNA fingerprinting) and paternity results from 130 families over 3 years. Male care was variable but unrelated to parentage, and males were observed to provide typical amounts of parental care to broods in which they had no parentage. Individual males' within-pair parentage generally declined within a season (with re-nesting), varied inconsistently between years and was unrelated to age or breeding experience. Survival between breeding seasons was low (30%) and independent of within-pair parentage. These patterns collectively suggest that the benefit of facultatively reducing parental care when parentage is reduced rarely exceeds the costs. Thus, selection for parentage-dependent care is apparently absent or weak, which could explain the absence of parentage-dependent care in this population of yellow warblers.
Birds were color banded, nest searches and parental care observations