Golden Eagle deaths prompt investigation

Associated Press

Originally published 07:49 a.m., March 27, 2008
Updated 07:53 a.m., March 27, 2008

CODY, Wyo. _ More than a dozen golden eagles have flown into power lines east of Worland and been electrocuted since December, prompting a federal investigation.

Most of the birds were killed by power lines in the Cottonwood Oil Field, Rocky Mountain Power spokesman Jeff Hymas said. The company owns the lines and is working to correct the problem, he said.

The Worland area has seen more eagles than usual in recent months, likely because of an increased number of rabbits and nonresident eagles, Hymas said.

"These and weather issues have likely contributed to the recent increase in Cottonwood Oil Field eagle mortalities," he said.

The electric power industry has made progress over the past 20 years in reducing deaths of birds, including golden eagles, a federally protected species, said Dominic Domenici, the resident agent in charge of Wyoming and Montana for the U.S. Fish and Wildlife Service.

Domenici said his agency is investigating the oil field deaths and is working with the U.S. Attorney's Office on the matter. He declined to discuss the case.

Rocky Mountain Power modified more than 900 power poles in the oil field after 35 eagles were killed in the area in 2000 and 2001, Hymas said. That work included placing protective covers over insulators and other power pole equipment, he said.

From January 2003 through October 2007, only five eagles were reported killed by power equipment in the area, Hymas said.

"To address recent cases of eagle deaths, the company has modified 15 power poles in the area where eagle remains have been found recently to make them more avian-safe," Hymas said in a story for Thursday editions of the Billings Gazette. "We want to do everything we can to reduce or eliminate eagle mortalities."

Eagles and other large birds can be electrocuted when their wings make contact with two power lines — closing an electric circuit — or other points on poles where equipment may pose a hazard, Hymas said.

"The golden eagle is at the most risk because it has the widest wingspan — 7 feet or more in many cases," said Charles Preston, curator of the Draper Museum of Natural History at the Buffalo Bill Historical Center in Cody, and author of the book "Golden Eagle: Sovereign of the Skies."

"They're attracted to poles because they are great vantage points for them to hunt from," he said.

Preston said he was unfamiliar with the specifics of the Cottonwood Oil Field deaths, but that weather changes or boosts in prey populations can be factors in increased electrocutions.

He added that golden eagles can live to be 30 years old but typically don't reproduce quickly, so their mortality rates are worth monitoring.

Ideally, power lines or other contact points should be at least 60 inches apart, Domenici said. Birds' feathers may brush two lines without incident in dry weather; but when feathers are wet, previously safe perches can turn deadly, Domenici said.

Overall, the power industry has done a good job of adopting standards developed for building new power lines so they are safe for birds, he said. But Wyoming's dry climate means many old, nonconforming poles are still in service.

The Cottonwood Oil Field poles were installed in the late 1950s and early 1960s, Hymas said. He said they don't meet the company's standards for avian-safe new construction, but that Rocky Mountain Power continues to monitor and evaluate its equipment, making improvements when necessary.

Rocky Mountain Power serves Worland and much of the Bighorn Basin, and has 129,000 customers in Wyoming, Hymas said.