Abstract
The Japanese White-eye Zosterops japonicus is known to rob nectar from a range of introduced flowering plants. Hibiscus Hibiscus cv. flowers pierced by white-eyes for nectar robbing were surveyed on Chichi-jima, Bonin Islands, Japan, in 2009. Nectar production did not commence in hibiscus flowers until 04:00. White-eyes began robbing nectar after 06:00, and continued throughout the morning. White-eyes were only rarely observed robbing nectar during the afternoons. Nectar robbing from buds, or closed flowers, was not observed. Nectar volume and sugar concentration was correlated with flower size, respectively, and larger flowers were robbed more often than smaller ones. The Japanese White-eye seemed to choose large flowers with plentiful nectar and rob them during the optimal period when nectar secretion was at its maximum.
