Damage to cherry blossoms by nectar-robbing Eurasian Tree Sparrows

Abstract

Eurasian Tree Sparrows Passer montanus feed on the nectar of cherry blossoms Cerasus x yedoensis without carrying pollen. This nectar-robbing behavior causes the blossoms to fall prior to pollination. Since cherry blossoms are cherished in Japanese culture, the public may be disturbed by nectar-robbing sparrows. We estimated blossom damage by sparrows in Goryo-kaku Park in Hakodate City, Hokkaido, Japan, a famous cherry blossom viewing spot. We estimated that the proportion of flowers caused to fall because of sparrows was 0.19% to 0.49% of all flowers.