Lovesick Birds Change Their Tunes Near Noisy Oil Fields —

Savannah sparrow

Savannah sparrow

Birds, to be heard above the din, are capable of changing their tunes in a complex ways. Researchers in Alberta, Canada, have discovered this fact after analyzing hundreds of hours of Savannah sparrow love songs.

 “They’re tailoring their songs depending on which part of their message is the most affected,” said Miyako Warrington, a University of Manitoba biologist who led a recent study on how sparrows cope with noise from the oil and gas infrastructure that dots Canada’s landscape. “This seems to show a complex level of adaptation. It’s not just everybody talking louder.”

Dr. Warrington is one of a growing number of scholars who study the noise generated by human activity — drills, turbines, roaring jet engines — and how that affects the natural world around us.

Mining on the fringes of the Brazilian rain forest, for instance, is disrupting the calls of local black-fronted titi monkeys, a study found last year. Whales and dolphins are known to be particularly vulnerable to the groans of ship engines or offshore drilling, which can disrupt the complex ways they communicate. Research has shown that noise pollution has doubled the background sound levels in more than 60 percent of protected areas in the United States.

And humans are not immune to the din. Epidemiologists have linked traffic noise to cardiovascular and other diseases.

Scholars of bird song have long noticed that avian city dwellers sound different from their peers in the country. But Dr. Warrington wanted to understand how wild birds adapt to the pumps and drills that oil and gas development has brought to wide swaths of North America.

Researchers have found that each bird, of course, adds its own quirks to its songs. To better understand an overall pattern of changes, the team tracked and recorded 73 male Savannah sparrows at 26 sites within 200 kilometers, or about 125 miles, of the city of Brooks, at the heart of Canada’s oil country.

The researchers looked at sites near four types of oil and gas infrastructure: grid-powered screw pumps, generator-powered screw pumps, compressor stations that pump natural gas from wells and oil-well pump jacks with the “nodding head” pumps. The team also recorded birds at sites with no oil infrastructure.

Over all, the team found that birds altered their songs most near generator-powered screw pumps. The most common difference was in pitch and in the opening notes and buzzy parts of their songs. Researchers did not find that the content of the songs changed.

There was no consistent change to the final trill. That appeared to be a personal flourish that male sparrows changed at whim. 

Dr. Warrington and her colleagues are now looking at how changes to songs can affect a bird’s reproductive chances. Separate research on mountain bluebirds and ash-throated flycatchers in New Mexico showed signs of chronic stress in birds exposed to steady noise from oil and gas infrastructure. In some cases, their chicks showed signs of stunted growth.

“The birds are altering their signals — but are these birds fine then? No, evolution doesn’t work like that,” said Nathan Kleist, a postdoctoral researcher in conservation biology at Colorado State University and a lead author of the study in New Mexico. Industrial noise, he said, “is having impacts on wildlife that we are just now beginning to understand.”

In an early encouraging sign, a follow-up study of female Savannah sparrows’ mating behavior — reciprocal calls, flirtatious wing flicks, annoyed attacks — showed that the male birds may be successfully wooing their belles with their modified tunes. (The New York Times – 13-03-2018)

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