A 7-year study of the impact of wind development on Greater Prairie Chickens came out in May, 2013 with the suprising result that wind development has no negative impact on the population of the birds. In fact, it found evidence of positive impact on the suvival of the females. A summary of this study is here, and its official write-up is here.
Highly regarded scientist Paul Kerlinger, who specializes in birds, has written an insightful piece (published Aug. 1, 2013) supporting the relative safety of wind turbines for bald eagles. Writes Kerlinger: "If an eagle is found dead at a wind facility, turbine owners must insist that the federal authorities allow the carcass to be analyzed to determine whether lead poisoning was involved. Eagles having even slightly elevated lead levels can be weakened and fly erratically, causing them to collide with various objects. In the event that the bird has elevated lead levels, the ultimate responsibility for the fatality may not be the turbine. Instead the agency [U.S. Fish and Wildlife Service] that funded and licensed the lead dispersal should accept responsibility." The full article is here, and we recommend it also for the other insights it contains.