Some 1500 wind turbines in California's Altamont Pass will be shut down each winter to protect migratory birds and 3000 older turbines will be replaced with state-of-the-art models following a preliminary decision by the Alameda County Board of Supervisors to add nine conditions to new 13-year use permits for about 3000 Altamont wind turbines. The permits will be up for renewal by the supervisors next month. If the board gives final approval to is preliminary ruling, about 750 turbines will be shut down each November and December. A second set of 750 turbines will be turned off in January and February. Wind farm owners will permanently close about 100 of the turbines giving birds most trouble and phase in 3000 new turbines, which rotate more slower, over the next 13 years. Cost is estimated to be $540 million. Conversion to more efficient and powerful turbines is expected to allow operators to maintain production at current levels despite the rulings. An estimated 1700-4700 birds are killed each year in the 50-square-mile Altamont Pass Wind Resource Area. Many of the fatalities are federally protected raptors. Following the county board's action, environmentalists are still vowing to move ahead with a lawsuit in state court against the ten Altamont wind companies. The lawsuit charges the wind companies with criminal violations of state and federal wildlife protection laws and unfair business practices under California's Unfair Competition Law. That case is expected to go to trial by the end of 2005.