Bald Eagle and Golden Eagle Mortalities at Wind Energy Facilities in the Contiguous United States

Abstract

The wind power plant on the island of Smøla, western Norway, is currently the largest in Norway; it has 68 turbines with nominal capacity of 2-2.3 MW each, hub height of 70 m and rotor blade radius of 38-41 m,. It was constructed in two phases between 2001 and 2005. Approximately 60 White-tailed Eagle Haliaeetus albicilla territories are found in the whole Smøla archipelago. Before construction there were 13 Eagle pairs holding territories in the wind farm area and within 500 m of it, whereas in 2009 this was reduced to only five. Since 1996, baseline data on the White-tailed Eagle population size and reproduction have been collected.In a post-construction study, 50 fledglings were satellite-tagged during 2003-2009, of which 45 provided more than 80 000 GPS positions in total. In addition to the geographical location, data on altitude and flight speed were provided by the transmitters (Microwave Telemetry, Inc., Columbia, MD, USA). Juveniles of both sexes stayed within the Smøla archipelago during their first winter. Most individuals moved away from the area during spring in their second year (April-May). Females dispersed further than males, often more than 800 km during summer, generally to the north. There was a return movement to the natal area during the second autumn. The same pattern was repeated in the third and fourth years for females, while the males showed more philopatry (Bevanger et al., 2009).From August 2005 to May 2010, four of the satellite-tagged birds were killed by collisions with turbines, of 36 White-tailed Eagles in total, involving 20 adults, nine immatures and seven juveniles. April and May are the months with the highest collision frequencies, with 13 (c. 36%) and nine (c. 25%) of the known fatalities.Risk assessments were performed based on GPS positions during the different months of the year and the age of the birds. The transmitters were programmed to transmit their positions at different intervals. Long time intervals (up to 24 h) were used during winter, 3-6 h during spring and autumn, and 1-3 h during summer. An analysis of moves showed that the birds changed positions on average 15 times per day, using a 100-m difference between positions as an indicator of movement. Every change in position was considered to involve a collision risk when the birds were at Smøla and its archipelago. Moves when they were elsewhere were not considered. Monthly 95 and 50% utilization distributions (UDs) (Worton 1989) were produced using the positions from the Smøla archipelago only, with all birds in each month and age-class pooled. The expected number of moves by each bird was estimated by weighing the number of obtained positions by a factor equal to 15 divided by the preprogrammed number of positions taken for each transmitter and month. The total number of expected moves (Me) was then obtained by summing over all birds for each calendar year and month. Kernel UD (95 and 50%) areas by calendar year and month (Ak95 and Ak50) were produced via ArcView 3.3, by using cross-validation and

Comparative Diets of Nesting Golden Eagles in the Columbia Basin Between 2007–2013 and the Late 1970s

“…Some recent studies and syntheses have indicated that Golden Eagles may be declining at least in some regions of North America (Kochert and Steenhof 2002, Hoffman and Smith 2003, Smith et al 2008, although recent reviews , Nielson et al 2014) have indicated that Golden Eagle populations are generally stable in the western U.S. Nielson et al (2016) suggested that this stability may be short-lived due in part to human-caused decline in habitats used by Golden Eagles. Anthropogenic landscape use and changes related to spread of invasive species (Kochert et al 1999), exurban expansion (Boeker 1974, Scott 1985, agricultural development (Beecham andKochert 1975, Craig et al 1986), recreation (Scott 1985, Watson 2010, Kochert et al 2002, Steenhof et al 2014, and energy development (Madders and Walker 2002, Rowland et al 2011, Pagel et al 2013 can negatively affect Golden Eagle reproduction and/or survival. Grasslands, sagebrush steppe, desert shrub, and other open landscapes provide important Golden Eagle habitat in the western United States and are undergoing especially rapid changes from human land use, altered fire regimes, and invasive species (Davies et al 2011).…”

Boreal bird abundance estimates within different energy sector disturbances vary with point count radius

“…Of specific concern are fatalities of species of conservation concern (e.g., Western Burrowing Owl [Athene cunicularia hypugaea]; Smallwood et al 2007) and species with small populations, delayed maturity, long lifespans, and low reproductive rates, for which even a few mortalities can have population-level effects (e.g., Golden Eagle [Aquila chrysaetos]: Lovich 2015; White-tailed Eagle [Haliaeetus albicilla]: Dahl et al 2012). While the number of birds affected is uncertain (Pagel et al 2013), estimates adjusted for searcher detection and scavenger removal suggest that between 140,000 and 328,000 birds are killed annually by collisions with turbines at wind energy facilities in the contiguous U.S. (Loss et al 2013). For songbirds in particular, fatalities at wind energy facilities in the U.S. and Canada are estimated to be between 134,000 and 230,000 annually (Erickson et al 2014 Morinha et al 2014), suggesting that the direct effects of wind energy facilities are of concern globally.…”

Spatial and Temporal Patterns in Golden Eagle Diets in the Western United States, with Implications for Conservation Planning

“…Fish and Wildlife Service (U.S.F.W.S.) released ''Eagle Conservation Plan Guidance'' for proposed wind energy developments because of the risk of injury and mortality of eagles from collisions with wind turbines (Pagel et al 2013). One of the recommendations in this document is for compensatory mitigation actions that increase prey availability (U.S.F.W.S.…”