Abstract
According to 2 recent studies, the number of birds killed annually by collisions with wind turbines in the continental United States is between 140,000 and 328,000 (Loss et al. 2013 a) and between 214,000 and 368,000 in the United States and Canada combined (Erickson et al. 2014). Although these estimates clearly represent a substantial number of dead birds, when placed in the context of other human-related causes of bird mortality, it appears that avian conservation priorities should be reexamined. For example, each year in the United States an estimated 1.3 to 4 billion birds are killed by domestic cats (Loss et al. 2013 b), 365 to 988 million by collisions with buildings (Loss et al. 2014 a), 89 to 340 million by automobiles (Loss et al. 2014 b), and 6.8 million by communication towers (United States and Canada combined; Longcore et al. 2012). In another study, Conover et al. (2013) summarized the number of birds killed in the United States by human activities and found that wind turbines ranked seventh of the 8 causes considered (only collisions with aircraft ranked lower). In that analysis, fewer birds were killed by wind turbines than by oil ponds, communication towers, power lines, windows, automobiles, and hunters (Conover et al. 2013). Relative estimates of bird mortality due to various human-related causes in Canada are similar to those in the United States (Calvert et al. 2013).