Wind Energy and Wildlife Conservation White-Tailed Eagles (Haliaeetus albicilla) at the Smøla Wind-Power Plant, Central Norway, Lack Behavioral Flight Responses to Wind Turbines ESPEN LIE DAHL, 1 Norwegian Institute for Nature Research, P.O. Box 5685 Sluppen, NO-7485 Trondheim, Norway ROEL MAY, Norwegian Institute for Nature Research, P.O. Box 5685 Sluppen, NO-7485 Trondheim, Norway PERNILLE LUND HOEL, 2 Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway KJETIL BEVANGER, Norwegian Institute for Nature Research, P.O. Box 5685 Sluppen, NO-7485 Trondheim, Norway HANS CHR PEDERSEN, Norwegian Institute for Nature Research, P.O. Box 5685 Sluppen, NO-7485 Trondheim, Norway EIVIN RØSKAFT, Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway BA ˚ RD G. STOKKE, Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway ABSTRACT Evidence is increasing of bird mortality due to large-scale wind-energy development. Soaring raptors, such as the white-tailed eagle (Haliaeetus albicilla), have proven particularly vulnerable to collisions. In this study, we compared white-tailed eagle flight behavior both inside and outside of the Smøla wind- power plant on coastal Central Norway. During the eagle breeding period (mid-Mar–end May 2008), we collected data on flight activity (directional flight, social behavior, and soaring) and flight altitude (below, within, and above the rotor-swept zone [RSZ]) at 12 vantage points; 6 within the wind-power plant and 6 outside (control area). We found that white-tailed eagles did not show any clear avoidance flight responses to the wind turbines. Hence, we found no significant differences in the total amount of flight activity within and outside the power-plant area. However, we found less flight activity among adults than among subadults within the power plant compared with the control area. We also found a slightly increased probability of flight activity in the RSZ within the power plant, which obviously may increase the risk of collision with wind turbines. Our findings may help explain the relatively high mortality rate of white-tailed eagles in the wind- power-plant area and the recorded peak in eagle fatalities during the breeding season. ß 2013 The Wildlife Society. KEY WORDS behavior, collision, flight response, Haliaeetus albicilla, mortality, Norway, Smøla, white-tailed eagle, wind turbines. Global warming and climate change scenarios (e.g., IPCC 2007), have boosted the focus on renewable energy, such as wind power, over the past 2 decades. In coastal Norway, several wind-power plants have already been constructed or are under construction. In 2011, Norway and Sweden estab- lished a common green certificate market for the production of renewable energy; thus, several more wind-power plants are likely to be built (Ministry of Petroleum and Energy 2010). The cumulative impact of existing and future wind- energy projects on bird populations is a major concern (Drewitt and Langston 2006). There is increasing evidence of bird mortality due to large-scale wind-energy develop- ment (Hunt et al. 1998, Johnson et al. 2002, Langston and Pullan 2003, Barrios and Rodriguez 2004, Drewitt and Langston 2006), especially in regard to raptors (Madders and Whitfield 2006, de Lucas et al. 2008, Smallwood and Thelander 2008, Bevanger et al. 2010). Although bird mortality due to artificial air obstacles is recognized to be a site- and species-specific problem (Bevanger 1994, Bevanger 1998, Janss 2000, Drewitt and Langston 2008), high-risk factors are still poorly understood, including the impact of species-specific flight behavior. Energy consumption during flapping flight in birds increases with increasing body mass; thus, soaring flight is common for large birds (such as, e.g., eagles [Hedenstrom 1993, Spaar 1997]). Soaring flight requires thermal updraft, and these rising air currents are used by raptors to provide lift and to maintain and gain height with a minimum energy cost. Soaring flight by using rising air currents is highly ener- gy-efficient (Kerlinger 1989), and studies of migrating rap- tors have shown that eagles spend >95% of their flight-time Additional supporting information may be found in the online version of this article. 1 E-mail: espenlie.dahl@nina.no 2 Present address: Norwegian Water Resources and Energy Directorate, P.O. Box 5091 Majorstua, N-0301 Oslo, Norway. Wildlife Society Bulletin 37(1):66–74; 2013; DOI: 10.1002/wsb.258 66 Wildlife Society Bulletin  37(1)