Many people around the globe love birds. But few realize that they may be doing more harm than good. A new study by Griffith University in Australia and the University of Auckland, New Zealand found this. The latest research, published in Proceedings of the National Academy of Sciences by the researchers, was based on earlier research about backyard bird-feeding practices in New Zealand. They examined the impact of different bird-feeding practices on particular species and whether supplementation feeding with bread and seeds favors certain species. People who feed birds in their gardens can cause damage to New Zealand’s grey warbler (Gerygone Igata). Introduced species are more likely to be benefited by feeding birds. They discovered that the common sparrow and Streptopelia Chinensis, two of the introduced species, were the most affected. Common sparrow and spotted dove abundances were 3.6 times and 2.4x higher, respectively, at the feeding stations. The species, which was named Bird of the Year in 2007, by New Zealanders (Gerygone.igata), has seen its abundance drop significantly at the feeding stations. Josie Galbraith from the University of Auckland is a PhD candidate. She says that the study on the grey warbler (Gerygone igata), whose song can be heard throughout New Zealand’s forests, has alarming results. Ms. Galbraith stated that while they typically feed on insects under the trees, their efficiency in foraging may be affected by disruptions to higher numbers of birds at feeder sites. “This study was co-authored by Ms. Galbraith. They monitored 23 North Shore garden over a 18-month. 12 had bird food, while eleven gardens did not. Spilopeliachinensis, a spotted dove that isn’t a native New Zealand bird, can thrive when gardeners put out bird food. They recorded a total number of 33 bird species as well as 18,228 individuals during the monitoring period. Myna, silvereye and blackbirds were the most frequent species. To thrive, spotted doves are especially fond of bird feeding. They found that the number of doves in the area rose rapidly at the beginning of feeding. This suggests that the species is moving from other areas to feed. University of Auckland Senior Lecturer Dr. Margaret Stanley was co-author. She said that the work suggests that bird-feeding favors have introduced spotted doves to replace native birds. Proceedings of the National Academy of Sciences. Published May 4, DOI: 10.1073/pnas.1501489112. Video: New Zealand, the Land of Birds
