Humankind on Earth is desperate for energy. Fossil fuels including coal, oil, and natural gas have served as the main energy source since oil’s discovery by Colonel Drake in Titusville, Pennsylvania during 1857, with the first well drilled in 1859 (Hubbert 1949). However, 2 issues have become gravely important regarding our use of fossil fuels. It is estimated that there are <44 years of oil remaining, with primary oil fields already showing declines in production (BP 2015). Secondly, continued fossil fuel consumption will only exacerbate effects of global climate change (Baes et al. 1977). Therefore, the search for new sources of renewable energy not based on fossil fuels has begun. One promising source is wind energy. Consequently, we invited the key scientists, knowledgeable on wind energy impacts on wildlife, to contribute to this Special Topic volume. We hope that you agree after reading these papers that wind energy development is an important energy source, but also a profoundly important mortality factor for 2 ecologically important types of wildlife: our avifauna and chiropterans.