Backyard Bird Feeders Harm the Natives
Bird feeders benefit invasive species, not native ones
Josie Galbraith, a PhD student from the School of Biological Sciences at the University of Auckland, experimented by setting up more than 20 urban feeding sites and watching them for 18 months. The results demonstrated that feeding actually favours non-native birds, like spotted doves and sparrows, whose populations dramatically increased.
Native birds, especially the gray warbler, suffered even though they do not compete for the food on the feeders. Their numbers decreased due to competition for habitat from the increasing non-native species. Similar results are predicted where feeders are popular anywhere in the world.