Noise and Light Pollution Affect Breeding Habits in birds

Looking for a bird's-eye view of human impacts? A new study, published in the California Polytechnic State University Library, provides the most comprehensive picture yet of how human noise and light pollution affect birds throughout North America. Noise pollution is when a developed building or area produces loud sounds for a prolonged time and light pollution is when there are too many sources of artificial light in an outdoor area.

The effects of noise and light pollution on the health of bird populations had been largely overlooked until recent studies suggested that these stressors can harm individual species. Researchers looked at a huge collection of datasets -- including those collected by citizen scientists -- to assess how light and noise affected the reproductive success of 58,506 nests from 142 species across North America.

The biologists found that light pollution, caused by street lamps and city lights, causes birds to begin nesting up to a month earlier than normal. The consequence can result increased immortality rates for baby birds -- hungry chicks may hatch before their food is available. When considering noise pollution, from man-made machinery, results showed that birds living in forested environments tend to be more sensitive to noise. Noise pollution delayed nesting for birds whose songs are at a lower frequency and thus more difficult to hear through low-frequency human noise.

The study is the first step toward a larger goal of developing a sensitivity index for all North American birds. The index would allow managers and conservationists to cross-reference multiple physical traits for a species to assess how factors such as light and noise pollution would affect it.

Although birds live in the same world we do, they experience it in a profoundly different way.