Click photo to enlarge
A raptor spreads its wings and glides effortlessly between two Altamont Pass windmills.

Efforts to reduce bird kills in the Altamont Pass Wind Resource Area may not be working, new data released this week show.

The mortality rate increased 27 percent over two years among raptors targeted in an ongoing monitoring study, according to an executive summary of the data issued by Alameda County's Scientific Review Committee. The five member panel advises the county on progress being made to mitigate bird deaths in the Altamont Pass windmill area.

The data was gathered from October 2005 to October 2007 during a monitoring study in the Altamont Pass area; the study is continuing into next year.

The increase in the kills of the four targeted raptors — the golden eagle, red-tailed hawk, American kestrel and burrowing owl — is in comparison with a baseline study that took place between March 1998 and May 2003.

The new data estimate a total of 2,236 birds from the four targeted species were killed annually.

Only the golden eagle saw a decrease in kills during the current study, with its mortality rate down 21 percent.

The full study — only the executive summary was released Tuesday — is expected to be released this week.

The latest numbers are not shocking. Late last year, the review committee intimated measures taken by wind-power companies in the area have not done enough to achieve a 50 percent reduction in raptor deaths by November 2009.

The 50 percent reduction was part of a settlement reached in January 2007 from a 2006 lawsuit filed by the Golden Gate Audubon Society, Californians for Renewable Energy and four other local Audubon chapters challenging the county's decision to renew permits for Altamont Pass wind turbines.

The committee's concerns caused some windmill operators to agree to keep their turbines off beyond an agreed upon two-month winter shutdown. The committee also re-catorgorized nearly 100 turbines to the two levels of highest-risk windmills that contribute to bird kills. High-risk turbines need to be removed or relocated to also help reduce the rate of kills in the area from birds that fly into the blades.

"Obviously, we're deeply distressed" by the latest numbers, said Elizabeth Murdock, executive director of the Golden Gate Audubon Society, which serves Alameda, Contra Costa and San Francisco counties and was a plaintiff in the 2006 lawsuit that led to the settlement.

Murdock tempered her comments on the numbers, however, pointing out that the two key elements to reduce bird kills — a winter shutdown of the turbines and removal of the highest-risk windmill in regards to avian mortality — did not take place in full at least until early 2007.

The summary also indicated that the population of the bird species in question also may have increased in the area.

Nevertheless, Murdock said the numbers of kills in the area have not gone down and that is of concern.

"There is no doubt that the numbers are going up and that's disconcerting," Murdock said.

Steven Stengel, a spokesman with FPL Energy, which has turbines in the Altamont Pass, said he wanted to reserve full comment until the complete study is released this week, but did say FPL remained committed to decreasing bird kills while generating green power.

"We want to be part of the solution," Stengel said. "It is our goal and objective to reduce the number of bird collisions in the area. We will continue to work with (the other parties) on this issue."

Chris Gray, chief of staff for county Supervisor Scott Haggerty — whose district contains the windmill area — reiterated those comments, saying the county also remains committed to finding a balance between reducing bird kills and creating clean energy at the wind-resource area, where approximately 5,500 turbines operate. Gray said "re-powering" may be one possible solution, where larger, more efficient windmills replace a handful of the smaller turbines currently in the Altamont area. Some studies say the larger windmills kill fewer birds, because of their size and slower movement.

Murdock said that could be a solution worth looking in to.

"If these studies do show these types of windmills reduce bird kills, it's a tremendous win-win situation for everyone," Murdock said.

To read the executive summary, go to www.altamontsrc.org.

Reach Chris Metinko at 510-763-5418 or cmetinko@bayareanewsgroup.com.