...Most birds killed at wind turbines (click here) are song birds. Migratory songbirds often migrate during the night at altitudes generally above rotor swept areas when weather conditions are favorable. Risk may be greatest during take-off and landing where wind facilities abut stopover sites. Studies have indicated that the level of bird use at the site and the behavior of the birds at the site are important factors to consider when assessing potential risk. For example, raptor fatalities appear to increase as raptor abundance increases. Certain species – including red-tailed hawks (Buteo jamaicensis) and golden eagles (Aquila chrysaetos) – that forage for prey in close proximity to turbines appear to have increased fatalities, while others like common ravens appear to avoid collisions with turbines.
All studies of bat impacts have demonstrated that fatalities peak in late summer and early fall, coinciding with the migration of many species. Bat fatalities also occur during spring migration for some species at some facilities. Several species of bats are vulnerable to collisions with turbines. Three migratory tree-roosting species seem to be particularly vulnerable: the hoary bat (Lasiurus cinereus), Eastern red bat (Lasiurus borealis), and silver-haired bat (Lasionycteris noctivagans).
There is also evidence that ground nesting birds, such as prairie-chickens and sage grouse, may avoid areas with wind turbines. It is believed that they avoid structures that could be used as perches for predators such as raptors. Turbine strings or arrays may also affect the habitat, causing the birds to search for less disturbed habitat. This can disrupt their breeding and nesting behaviors, resulting in fewer chicks surviving to adulthood....
