Noise from oil and gas pumps can be a real mood-killer for a male sparrow trying to attract a mate, but a team of biologists in southern Alberta has discovered that songbirds are finding ways to cope.
Their research involves high fidelity speakers, powerful microphones and many early morning hours spent on a patch of prairie near the small city of Brooks.
They blast recordings of various types of oil and gas pumps through the speakers and then track and record the birds’ response. The acoustic experiments are producing intriguing results.
One songbird species, the Savannah sparrow, appears to be adapting its love songs with a high degree of complexity.
“They’re doing whatever they can to make the sound go further,” said Nicola Koper, a conservation biologist from the University of Manitoba’s Natural Resources Institute who is involved in the research.
After all, the birds have flown all the way up from the southern U.S. on important business: to breed and raise their young.
Fastest declining avian group in Canada
The mixed grass prairies in southern Alberta serve as a bug buffet and a nursery for grassland birds, but their territory has shrunk.
“We’ve converted so much of our grassland habitat to cropland, that grassland birds are declining more rapidly than birds of any other ecosystem across North America, including in Canada,” said Koper.
“We need to be really careful with how we manage the grasslands we have left, because they’ve already lost so much,” she said.
For Koper, that includes a habitat’s acoustic ecology.
A group of scientists, including Koper, tracked 73 Savannah sparrows near four types of oil and gas pumps for a study recently published in the scientific journal The Condor: Ornithological Applications.
‘Cocktail party’ effect
They found the birds were changing their tune at the noisiest sites, which featured a generator-powered screw pump.
The sparrows sang parts of their mating calls at a higher pitch, so they could be heard above the din.
“It’s like having a conversation at a cocktail party. You repeat or you modify what’s important to be heard. So, if it’s your name that is important, you’ll keep repeating the name and it’s a similar thing,” said Miyako Warrington, one of the authors of the study.
The birds also delivered their opening note at a lower pitch than usual, which may seem counterintuitive, but as Warrington explained, lower frequencies have longer wavelengths that don’t do as much bouncing off surfaces, therefore they can travel further.
The adaptations are difficult to pick out with the human ear, but they’re visible in spectrograms.
It would seem Savannah sparrows have got game.
Or do they?
Savannah sparrows may be finding a way to cut through the industrial ruckus, but Warrington says it’s still not clear whether females are picking up what the males are putting down.
Warrington wonders if desirable males are losing their edge as they alter their songs to compete with noisy oil pumps.
“Let’s say you’re a male and you sound like George Clooney. You sound super sexy, right? And ladies come. And then you change your voice and you sound more like Bart Simpson and now maybe when you do your mating call the ladies are going to be like, ‘Ah, maybe I’ll pass,'” said Warrington.
“Even though they’re able to do it, is it still hurting them?”
The researchers are trying to learn more about that Clooney conundrum this summer with more acoustic experiments on different songbird species, including the Baird’s sparrow.
Koper hopes oil and gas companies will be able to put the information to use, perhaps by opting for quieter pumps, underground infrastructure or fencing built to baffle the noise.
Since 2000, more than 170,000 conventional oil and natural gas wells have been drilled in Alberta, according to the provincial government.