Birds and wind farms

New Scientist News - Wind turbines a breeze for migrating birds

Migratory birds learn to avoid wind farms, at least in Denmark. But resident birds may not fare so well. For example, the wind farm in the Altamont pass in California has killed a lot of raptors.

The subsections in the reports on the Wind Power and Bird Studies page suggest there may be other environmental factors, e.g. grassland vs. desert vs. prey populations.