Animal Predatory Behavior Decreases Near Desert Wind Turbines, Study Finds

"These findings could be helpful in assisting managers to design future wind energy facilities with species in mind."

Wind turbines overlooking Whitewater Creek and Interstate 10 near Palm Springs, California. (PHOTO: David McNew / Getty Images News / Getty Images)

By Patch CA (Patch Staff)
Patch Banning

PALM SPRINGS, CA – A study conducted at the windmills near Palm Springs showed that predators are less likely to attack prey living near the wind turbines, including desert tortoises that burrow in the Coachella Valley.

Researchers from the University of California, Davis and the U.S. Geological Survey employed motion-activated cameras facing the entrances of 46 active desert tortoise burrows at the 5.2-square-kilometer wind energy facility.

They found that predators are far more likely to visit the tortoises' burrows near dirt roads and far less likely to visit burrows close to turbines.

The five predator species monitored included bobcats, gray foxes, coyotes, black bears and western spotted skunks, who scientists say were not actively hunting the tortoises but seeking smaller prey that frequently live in desert tortoise burrows.

"These findings could be helpful in assisting managers to design future wind energy facilities with species in mind," said lead author Mickey Agha. "There may be benefits to adding space between turbines and increasing the number of dirt roads, to potentially provide habitat for sensitive terrestrial wildlife."

Scientists behind the study -- which was published in the April issue of The Journal of Wildlife Management -- say the findings show that the design of wind energy infrastructure impacts animal behavior, an area of study rarely touched on.

"There is little information on predator-prey interactions in wind energy landscapes in North America, and this study provides a foundation for learning more," said Jeffrey Lovich, USGS scientist and study co-author.

"Further investigation of causes that underlie road and wind turbine effects, such as ground vibrations, sound emission and traffic volume, could help provide a better understanding of wildlife responses to wind energy development," he said.

Army seeks to move more than 1,100 desert tortoises

Desert tortoise. (Rachel Wilson)

Julie Cart
Los Angeles Times

As it prepares to expand training operations at Ft. Irwin in the Mojave Desert, the U.S. Army is again proposing to move more than 1,100 threatened California desert tortoises -- an unprecedented number of an endangered species that has not fared well during previous relocations.

The Army is seeking the approval of the federal Bureau of Land Management to move the tortoises from nearly 100,000 acres in portions of the National Training Center to lands managed by the BLM. The environmental assessment is under BLM review and the proposed action is open for a 15-day public comment period.

Moving desert tortoises is not always successful. The Army relocated more than 600 of the animals last year but suspended the $8.7-million program after the first phase when officials noted high mortality rates among the tortoises, chiefly because of coyotes.

About 90 animals were found dead from suspected coyote predation. But Clarence Everly, natural and cultural resources program manager at Ft. Irwin, said only one animal died during the relocation.

The sheer numbers of tortoises proposed to be moved in this latest operation, beginning next spring through 2012, alarms conservationists.

"Nothing's ever been done on this scale before," said Ileene Anderson, a biologist with the Center for Biological Diversity, who says a total of 252 tortoises have died in the translocation area. "Every time the animals recognize that they don’t know where they are, they have some built-in mechanism that tells them to head for home and they make a break for home."

In the last move, some tortoises traveled up to five or six miles to get back to their home range, Anderson said.

The relocation of desert tortoises from Ft. Irwin, northeast of Barstow, to the drought-ravaged western Mojave puts more pressure on the species, whose population is already crashing, in part because of an upper respiratory disease that afflicts some animals. Everly said the Army is blood testing every tortoise and will quarantine any found to have the disease.