06 May 2015:
Backyard Bird Feeders May Put
Native Species at a Disadvantage, Study Says
Ed Hoskins/Public domain
A sparrow eats at a backyard bird feeder.
Backyard bird feeders tend to attract aggressive, introduced bird species while discouraging native species that eat insects and nectar, essentially restructuring urban bird communities and skewing them toward non-native species, a new study
says. Data based on nearly 600 surveys of 18,000 birds from 33 species in New Zealand show that yards with bird feeders tended to attract non-native omnivores such as house sparrows, spotted doves, and blackbirds. Outdoor areas without bird feeders had significantly more native bird species such as the grey warbler, whose diet consists mainly of insects. In general, areas with bird feeders tended to have much less diversity than areas without feeders, according to the report published in the journal Proceedings of the National Academy of Sciences
. Although the population and diversity trends reversed when feeders were removed, the researchers say that over time bird feeders in urban areas likely give non-native species a competitive and reproductive edge over native bird species.
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