The effect of experience on parental role division in Ryukyu Scops Owl Otus elegans

Abstract

Parental role division is common among monogamous birds. Among raptors, males typically expend more effort to feed their chicks than do females, yet few studies have focused on how each pair establishes this role division. Therefore, in this study we examined the mechanism of role division in the Ryukyu Scops Owls Otus elegans on Minami-daito Island. Pairs of this species typically remain together and use the same nest over several years, so there is a possibility that their role division improves with experience over time. To clarify this, we studied the feeding frequency and territorial usage of individuals. Males fed their chicks more frequently than females, and experienced individuals using the same nests fed their chicks more than inexperienced individuals. On comparing experienced and inexperienced pairs, we found that experienced individuals hunted closer to the nest than inexperienced individuals. Furthermore, the home ranges of the males and females of experienced pairs, overlapped less than those of inexperienced pairs. Experience of using a nest site in consecutive years may allow such individual behavioural differences to develop and be involved in role division in parental care.