Birds select fruits with more anthocyanins during autumn migration


We evaluated whether fruit selection by autumn-migrating birds at an important stopover site in southern New England was related to water-soluble antioxidant content of fruits. We measured total anthocyanins, total phenolics, and total antioxidant capacity in fruits from common native and non-native plant species and related this to estimates of fruit selection by free-living birds. Birds selected certain fruits over others, with arrowwood (Viburnum recognitum, V. dentatum) consumed at the highest rate, followed by Virginia creeper (Parthenocissus quinquefolia) with much lower consumption of other fruits (e.g., oriental bittersweet [Celastrus orbiculatus], multiflora rose [Rosa multiflora], winterberry [Ilex verticillata]). Antioxidant concentrations primarily differed by shrub species and less so between sites. Arrowwood spp. had the highest total antioxidants, followed by Virginia creeper, northern bayberry (Myrica pennsylvanica), chokeberry spp. (Aronia prunifolia, A. melanocarpa), multiflora rose, winterberry, and oriental bittersweet. These results are consistent with the hypothesis that free-living birds select fruits based, in part, on antioxidant content. We suggest birds may actively select polyphenol/anthocyanin-rich fruits during autumn migration to protect themselves against the potentially damaging effects of oxidative stress caused by long-distance fasting flight.

Wilson Journal of Ornithology 125:97-108