Paternity and parental care in the black-throated blue warbler, Dendroica caerulescens

Much debate surrounds the relationship between male parental care and paternity. We quantified parental care of yearling (second year: SY) and older (after second year: ASY) male black-throated blue warblers and determined parentage with microsatellites over four breeding seasons. ASY males that had sired all young in their broods fed 7-day-old nestlings at higher rates than ASY males that sired only some of the young in their broods. This relationship was not present in yearling males. A negative relationship between level of paternity and paternal care may arise if males facultatively adjust their care in response to cues of paternity, if poor-quality males are both more likely to be cuckolded and less able to provide parental care, or if males reduce both mate guarding and parental care to pursue extrapair matings. Parental care given by ASY males was not associated with additional mating opportunities during the nestling period. Thus, pursuit of extra matings is unlikely to account for the association between paternity and parental care. ASY males in better condition had higher levels of paternity, but did not guard their mates more closely nor feed their young at higher rates. These results suggest that ASY males may be able to assess their paternity, possibly by using cues related to levels of local synchrony during their females' fertile periods, and adjust their care accordingly. Paternity obtained by SY males was not associated with local synchrony, however, suggesting that the apparent lack of a facultative response by males of this age class may be due to a lack of reliable cues to paternity. (C) 2001 The Association for the Study of Animal Behaviour.