Some of the first windmills that were installed in California turned out to be sited in the worlds premium raptor habitat. They are much more careful about where they put them now. The new windmills are much bigger and on much taller towers. The towers are tublar instead of latice towers which keeps the birds away. The bird mortality, even in dense bird populations, is about 1/4 as high with the same number of megawatts of windmills.
BTW how many birds do you suppose are killed by cars and trucks and power lines and polution. Windpower favors birds in the long run because it is clean.