Noise pollution negatively influences bird populations

Washington, July 26 (ANI): A new University of Colorado at Boulder study shows the strongest evidence yet that noise pollution negatively influences bird populations.

The three-year study compared nesting birds inhabiting pinyon-juniper woodland sites surrounding natural gas extraction sites and their noise-producing compressors with birds nesting in adjacent, quieter woodland sites.

While bird species richness declined at noisy sites, the bird nesting success was higher there than in the nearby quiet sites, according to Clinton Francis, of CU-Boulder's Department of Ecology and Evolutionary Biology, lead author on the study.

"This is the first study to show that noise pollution causes changes in species interactions within bird communities," said Francis.

"Since noise pollution can be a major cause of declining bird diversity in and around urban areas, better noise control using quieter road surfaces and sound-reducing walls and berms should be considered to help preserve such communities," he added.

The study was conducted in a parcel of woodland south of Durango, Colorado, just over the New Mexico border.

"While other studies have shown noise pollution can have negative impacts on bird species, most have been conducted near heavily used roads," said Francis.

The researchers found that 32 different bird species nested in the quiet areas undisturbed by noise pollution, while only 21 species were nesting in the noisy study sites.

The team also found only three bird species nested exclusively at the noisy sites, while 14 different bird species nested only in the quiet sites, according to Francis.

"Two bird species preferred the noisy sites," he said.

Ninety-two percent of the black-chinned hummingbird nests and 94 percent of house finch nests in the two study areas were found at sites near noisy compressors.

"The two species accounted for 31 percent of the nests at the noisy sites, but less than 3 percent on the quiet sites," said Francis.

The team determined that 97 percent of mourning dove nests and 100 percent of black-headed grosbeak nests in the study area were found in the quiet areas away from the din of compressors.

Francis said the low vocal frequencies of mourning doves and black-headed grosbeaks appear to overlap with most human-caused noises, which may inhibit vocal communication required for repelling rivals, pairing and nesting.

"The study indicated birds that were intolerant of noise and nested in quiet areas were subject to greater rate of nest predation than those in noisy areas," he said.

"Understanding how birds respond to noise, especially birds with critical links to ecosystems, are crucial in maintaining biodiversity in growing areas of landscapes disturbed by urban clamor," said Francis. (ANI)