Passerine pollination in a winter-flowering tree

Birds can be alternative pollinators for winter-flowering plants outside the tropics where low temperatures limit insect activity. Feng et al. observe pollinator visitation to loquat (Eriobotrya japonica, Rosaceae) and exclude birds and other animals from the flowers. They determine that in late winter two passerine birds (Pycnonotus sinensis and Zosterops japonicus) are effective pollinators, and that the perigynous flowers reward passerines with relatively large volumes of dilute nectar. The results suggest a possible association between perigyny and bird pollination.