July 19 (UPI) -- Oil and gas operations significantly alter the landscape and present a variety of pollution risks. In Alberta, Canada, they're also encouraging the parasitism of the brown-headed cowbird.
In a new study, published this week in the journal Royal Society Open Science, scientists report a four-fold increase in the number of brown-headed cowbirds occupying fields outfitted with oil wells or natural gas facilities.
An increase in wildlife abundance is often heralded, but the brown-headed cowbird isn't a normal bird. It's a parasite. The birds deposits their eggs into the nests of other species, tricking overworked mothers into raising their young.
"This increase in cowbird abundance led to dramatic increases in parasitism of nests," Nicola Koper, a professor in the Natural Resources Institute at the University of Manitoba, said in a news release. "I was shocked at how large the impact was."
The impact is being felt by vulnerable songbird species native to the Canadian prairie. The act of parasitism leads to increases in nest abandonment among songbirds, as well as higher rates of hatchling failure.
Larger imposters can also outcompete songbird hatchlings for food, and their louder cries can encourage higher rates of predation.
Field scientists found survival rates were significantly lower for parasitized Savannah sparrow nests.
Researchers believe oil and gas infrastructure offers cowbirds ideal perching locations, helping them locate vulnerable nests. Authors of the new study say oil and gas companies should be encouraged to reduce the number perch sites by burying power lines and limiting the construction of new roads.
"Our society is going to be dependent on fossil fuels for many more decades," said Koper, "but we can use these resources in ways that reduce their impacts on the environment."