Abstract
The Japanese White-eye Zosterops japonica is known to rob nectar from several kinds of flowering plants. Hibiscus Hibiscus rosa-sinensis flowers damaged by nectar-robbing White-eyes were surveyed at three sites through the year on Okinawa Island, southern Japan, from June 2010 to May 2011. The rate of damage to flowers during winter was significantly higher than during other seasons. In general, White-eyes appear to rob nectar from Hibiscus in winter when the available food sources are scarce. At the urban study site, however, the rate during spring and summer was occasionally higher than during winter. The cause of this difference in utilization of Hibiscus flowers at urban sites is unknown, but may be due to a difference in flower varities or food resources. The urban site may also have more human disturbance that may affect the behavior of birds. When the cherry (Taiwan Cherry Prunus campanulata) was in bloom, the rate of damage to Hibiscus flowers dropped from 32% to 13% at all sites. Since White-eyes were observed to take cherry nectar during the cherry blossom season, they may not need to rob nectar of Hibiscus flowers during the height of the blooming season for cherry.
