In response to your comment that wind turbines should be abandoned as an alternative energy system because of birds being killed by them: 

How many birds collide with wind turbines?

A: Only a few studies have examined the frequency of bird collisions for significant numbers of wind turbines — one in Denmark and two in California. These indicate that a bird will collide with a given wind machine no more than approximately once every 8 to 15 years. Higher levels of mortality have been found by some studies of smaller numbers of turbines in coastal locations with large concentrations of waterfowl, and it seems appropriate to use greater caution in siting wind projects in such areas or in known areas of high migration.

In the Altamont Pass Wind Resource Area (which has some 7,000 wind turbines), a two-year study found 182 dead birds, of which 119 were raptors. The study attributed 55 percent of raptor deaths to collisions with turbines, eight percent to electrocutions from power lines, 11 percent to collisions with wires, and 26 percent to unknown causes.

Q: How many birds die in collisions with other human structures?

A: It is estimated that each year, 57 million birds die in collisions with vehicles; 1.25 million in collisions with tall structures (towers, stacks, buildings); and more than 97.5 million in collisions with plate glass.

(via awea PDF)