Some birds thrive in noisy neighborhoods

Say you’re a scientist trying to study the effects of human-produced noise on bird communities in the wild, an interesting topic given how dependent birds are on vocal communication. You could choose a study area near a highway, perhaps, but that creates a problem: how to isolate the effects of noise from other effects, like the death of the occasional animal that strays onto the road. For Clinton D Francis, a doctoral student at the University of Colorado, the solution was an area with plenty of noise, but no traffic (or much else, either). The study sites were in a pinon-juniper woodland in northwestern New Mexico that is home to many natural-gas wells. Some of the wells have huge compressors that run constantly and sound like jet engines. “They’re definitely loud enough that you need ear protection if you spend even a few minutes near them,” Francis said.

Francis, with Alexander Cruz of the University of Colorado and Catherine P Ortega of Fort Lewis College, counted bird nests near compressor sites and near quiet wells that lacked compressors.

Unlike some earlier studies of the effects of road noise, they found no difference in the density of birds at both kinds of sites. But the noise did keep some kinds of birds away: the quiet sites had nests of 32 species, while only 21 species were found at compressor sites. The findings were reported in Current Biology. The researchers also studied reproductive success, how many eggs, hatchlings and fledglings were produced at the nests. Francis said he expected that the birds at noisy sites would have less reproductive success because they would not be able to hear the sounds of predators as they approached. But the study found that noisy sites were actually more productive, probably because the major predatory bird in the area, the Western scrub jay, doesn’t appear to like noise either. Very few of them were found at the noisy sites.

Henry Fountain
NYT News Service

Thinning clouds mean more global warming

Thinning clouds over the ocean exacerbate global warming by leading to more rapid temperature increases, according to a new study. The research combined data, collected by observers on ships and satellites, going back over a century. The effect clouds have on climate has been something of a mystery to scientists, with researchers hoping they would provide a silver lining by acting as a brake on climate change.

One possibility was that higher temperatures would mean more clouds, which in turn would bounce more of the sun’s radiation back into space, but this theory has not been reflected in the study’s findings.

Instead, researchers found that, as oceans become warmer, low-level clouds dissipate from the skies. This means more sunlight reaches the ocean surface - a runaway process that leads to more warming and less cloud cover. “This is somewhat of a vicious cycle, potentially exacerbating global warming,” Amy Clement, a professor of meteorology and physical oceanography at the University of Miami, said.

Tom Roberts
The Guardian

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