Comparing bird and bat fatality‐rate estimates among North American wind‐energy projects

Abstract

Estimates of bird and bat fatalities are often made at wind‐energy projects to assess impacts by comparing them with other fatality estimates. Many fatality estimates have been made across North America, but they have varied greatly in field and analytical methods, monitoring duration, and in the size and height of the wind turbines monitored for fatalities, and few benefited from scientific peer review. To improve comparability among estimates, I reviewed available reports of fatality monitoring at wind‐energy projects throughout North America, and I applied a common estimator and 3 adjustment factors to data collected from these reports. To adjust fatality estimates for proportions of carcasses not found during routine monitoring, I used national averages from hundreds of carcass placement trials intended to characterize scavenger removal and searcher detection rates, and I relied on patterns of carcass distance from wind turbines to develop an adjustment for variation in maximum search radius around wind turbines mounted on various tower heights. Adjusted fatality rates correlated inversely with wind‐turbine size for all raptors as a group across the United States, and for all birds as a group within the Altamont Pass Wind Resource Area, California. I estimated 888,000 bat and 573,000 bird fatalities/year (including 83,000 raptor fatalities) at 51,630 megawatt (MW) of installed wind‐energy capacity in the United States in 2012. As wind energy continues to expand, there is urgent need to improve fatality monitoring methods, especially in the implementation of detection trials, which should be more realistically incorporated into routine monitoring. © 2013 The Wildlife Society

Use of bird carcass removals by urban scavengers to adjust bird-window collision estimates

“…To date, estimates of carcass removal rates by scavengers and the bias created in estimates of avian mortality rates from human activities have been estimated primarily at wind farms, at power lines, and in pastures (Balcomb 1986, Tobin and Dolbeer 1990, Wobeser and Wobeser 1992, Ragg et al 2000, Kostecke et al 2001, Smallwood 2007, Prosser et al 2008, Ponce et al 2010, Smallwood et al 2010, Villegas-Patraca et al 2012, Bispo et al 2013, Smallwood 2013. Two studies have estimated carcass removal by scavengers in an urban landscape (Table 1).…”

Canadian Estimate of Bird Mortality Due to Collisions and Direct Habitat Loss Associated with Wind Turbine Developments

“…Although wind power is widely viewed as a clean alternative to fossil fuel-based energy generation, there has been some concern regarding the impact of wind farms on birds (Kern and Kerlinger 2003, Langston and Pullan 2003, Kingsley and Whittam 2005, Drewitt and Langston 2006, Barclay et al 2007, Smallwood 2013. Birds can be killed through collisions with turbines and other ancillary structures such as meteorological (met) towers or power lines, and through nest mortality if vegetation clearing, required for project development, occurs during the nesting season (Band et al 2007, Smallwood andThelander 2008).…”

Animal cognition in a human-dominated world

“…A further 573,000 are struck down by wind turbines, along with 888,000 bats (Smallwood 2013). Worldwide, unintended capture in fishing devices is recognized as the single most serious global threat to migratory, long-lived marine taxa including turtles, birds, mammals and sharks (Wallace et al 2013).…”