WASHINGTON – The Obama administration offered new guidance Friday on where wind farms should be located to reduce the number of bird deaths while promoting increased use of wind power.

Interior Secretary Ken Salazar said the guidelines, which take effect immediately, provide a scientific basis for developers and government regulators to identify sites with low risk to wildlife.

But a bird advocacy group that lobbied for mandatory standards said the new voluntary guidelines will do little to protect hundreds of thousands of birds killed each year by wind turbines.

Salazar called wind power a key part of the administration’s “all-of-the-above” energy strategy and noted that the guidelines for onshore projects have been endorsed by the American Wind Energy Association and the National Audubon Society, a conservation group.

The two endorsements “speak volumes about our goals: to do everything we can to stand up for renewable energy” such as wind power while protecting wildlife and habitat, Salazar said at a news conference Friday.

The guidelines call on the wind industry to eliminate from consideration areas that would pose high risks to birds and other wildlife, and to take steps to alleviate problems by restoring nearby habitat and other actions. If developers follow the guidelines, they are unlikely to be prosecuted under federal law in the event of bird deaths, said Dan Ashe, director of the U.S. Fish and Wildlife Service.

The American Bird Conservancy, an advocacy group that has pushed for mandatory standards, said voluntary guidelines are largely unenforceable and will do little to protect birds killed or injured by wind turbines.

The group “supports wind power when it is ‘bird-smart.’ Unfortunately, voluntary guidelines will result in more lawsuits, more bird deaths and more government subsidies for bad projects,” said Kelly Fuller, the group’s wind campaign coordinator.

Exact statistics for the number of birds killed by wind turbines are not available, but a 2008 study by a biologist with the Fish and Wildlife Service estimated that wind farms were killing about 440,000 birds per year in the United States.

The number of wind turbines has grown significantly since then, with overall output increasing from about 25,000 megawatts of electricity in 2008 to nearly 47,000 megawatts last year, according to the wind energy association.