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A large number of bat fatalities have been reported in wind energy facilities in different regions globally.Wind farm operators are required to monitor bat fatalities by conducting carcass surveys at wind farms. A previous study implemented the ballistics model to characterize the carcass fall zone distributions after a bat is struck by turbine blades. The ballistics model considers the aerodynamic drag force term, which is dependent upon the carcass drag coefficient. The bat carcass drag coefficient is highly uncertain; no measurement of it is available. This paper introduces a methodology for bat carcass drag coefficient estimation. Field investigation at Macksburg wind farm resulted in the discovery of three bat species: the hoary bat (Lasiurus cinereus), eastern red bat (Lasiurus borealis), and evening bat (Nycticeius humeralis). Carcass drop experiments were performed from a dropping platform at finite height, and carcass position time series data were recorded using a highspeed camera. Falling carcasses were subjected to aerodynamic drag and gravitational forces. Carcasses were observed to undergo rotation, often rotating around multiple axes simultaneously, as well as lateral translation. The complex fall dynamics, along with drop from a limited height, prohibit the carcasses from attaining terminal velocity. Under this limitation, the drag coefficient is estimated by fitting a ballistics model to the measured velocity. Multivariable optimization was performed to fit the ballistics model to the measured velocity resulting, in an optimized estimate of the drag coefficient. A sensitivity analysis demonstrated significant variation in the drag coefficient with a small change in initial position, highlighting the chaotic nature of carcass fall dynamics. Based on the limited sample, the bat carcass drag coefficient and terminal velocity were found to be between 0.70-1.23 and 6.63-17.57ms-1, respectively. The maximum distance carcasses are predicted to fall after impact with a typical utility-scale onshore wind turbine was computed using a 2-D ballistics model. Based on the range of drag coefficients found in this study, hoary and evening bats are estimated to fall within the rotor plane up to a maximum distance of 92 and 62 m, respectively, from the wind turbine tower. The ballistics model of carcasses after being struck by wind turbine blades can be used to obtain fall distributions for bats, guide carcass survey efforts, and correct survey data for limited or unsearched areas. [ABSTRACT FROM AUTHOR]

As development of wind energy facilities continues, questions of why fatalities of migrating insectivorous bats occur at turbines still remain. Numerous hypotheses have been proposed, including a feeding-attraction hypothesis that suggests bats may be attracted to insects congregating near turbine nacelles. To test this hypothesis, we analyzed echolocation calls of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats recorded over 72 nights at a wind energy facility in Southern Alberta, Canada. We recorded calls at 3 heights: 67 m at turbine nacelles, 30 m at meteorological towers, and ground level at turbines and meteorological towers. We used feeding buzzes as indicators of foraging behavior. We compared the occurrence of feeding buzzes across heights, and between turbines and meteorological towers to test the prediction that if bats are attracted to turbines for foraging, there will be a greater proportion of feeding buzzes at turbines, and in particular, at nacelle height. We found no significant evidence that foraging rates were higher at nacelle height compared to 30 m or ground level, or between turbines and meteorological towers for either species. For silver-haired bats, foraging activity was greater at meteorological towers, and in particular, at 30 m height. These results do not support the feeding-attraction hypothesis for silver-haired or hoary bats, and suggest that while some bats forage in the vicinity of wind turbines, they are not specifically attracted to turbines to feed. [ABSTRACT FROM AUTHOR]

Abstract Wind energy is rapidly growing as a renewable source of energy but is not neutral for wildlife, especially bats. Whereas most studies have focused on bat mortality through collision, very few have quantified the loss of habitat use resulting from the potential negative impact of wind turbines, and none of them for hub heights higher than 55 m. Such impacts could durably affect populations, creating a need for improvement of knowledge to integrate this concern in implementation strategies. We quantified the impact of wind turbines at different distances on the activity of 11 bat taxa and 2 guilds. We compared bat activity at hedgerows (207 sites) located at a distance of 0–1000 m from wind turbines (n = 151) of 29 wind farms in an agricultural region in the autumn (overall 193,980 bat passes) using GLMMs. We found a significant negative effect of proximity to turbines on activity for 3 species (Barbastella barbastellus , Nyctalus leisleiri , Pipistrellus pipistrellus), 2 species-groups (Myotis spp., Plecotus spp.) and 2 guilds (fast-flying and gleaner). Bat activity within 1000 m of wind turbines by gleaners and fast-flying bats is reduced by 53.8% and 19.6%, respectively. Our study highlighted that European recommendations (at least 200 m from any wooded edge) to limit mortality events likely strongly underestimate the loss of bat activity. The current situation is particularly worrying, with 89% of 909 turbines established in a region that does not comply with recommendations, which themselves are far from sufficient to limit the loss of habitat use. Highlights • High negative effect on bat activity of proximity to wind turbines for some species • Some of these species were so far unknown to be impacted by wind turbines. • Activity of gleaners and fast-flying bats close to turbines is reduced by 53.8% and 19.6%. • The impact occurs over 1000 m around wind turbines. • European recommendations are unapplied and far from sufficient for this impact. [ABSTRACT FROM AUTHOR]

Assessment of avian and bat collisions with wind turbines is necessary to ensure that the benefits of renewable wind power generation are not outweighed by mortality of protected species. An onboard, integratedmultisensor system capable of providingdetectionof turbine collision events, including taxonomic information, was developed. The conceptual design of a multisensor system including a vibration sensing node, an optics node, and an bioacoustic node with an event-driven trigger architecture was field-tested on utility-scale wind turbines. A pixel density computational modelwas built to estimate the spatial coverage and target resolution to the optimized configuration for camera placement. Field test results of the vibration node showed that nearly half of the recorded impact events were successfully identified by visual inspection and running short-time Fourier transform on recorded vibration signals. The remaining undetected impact events were masked under background noise due to lowimpact energy and high background noise of the operating turbine, which result in subsequent low signal-to-noise ratio. Our results demonstrate the feasibility of triggering the system through single impact event sensed by vibration sensors. [ABSTRACT FROM AUTHOR]

Wind turbines represent a source of hazard for bats, especially through collision with rotor blades. With increasing technical development, tall turbines (rotor-swept zone 50–150 m above ground level) are becoming widespread, yet we lack quantitative information about species active at these heights, which impedes proposing targeted mitigation recommendations for bat-friendly turbine operation. We investigated vertical activity profiles of a bat assemblage, and their relationships to wind speed, within a major valley of the European Alps where tall wind turbines are being deployed. To monitor bat activity we installed automatic recorders at sequentially increasing heights from ground level up to 65 m, with the goal to determine species-specific vertical activity profiles and to link them to wind speed. Bat call sequences were analysed with an automatic algorithm, paying particular attention to mouse-eared bats (Myotis myotis and Myotis blythii) and the European free-tailed bat (Tadarida teniotis), three locally rare species. The most often recorded bats were the Common pipistrelle (Pipistrellus pipistrellus) and Savi’s pipistrelle (Hypsugo savii). Mouse-eared bats were rarely recorded, and mostly just above ground, appearing out of risk of collision. T. teniotis had a more evenly distributed vertical activity profile, often being active at rotor level, but its activity at that height ceased above 5 ms-1 wind speed. Overall bat activity in the rotor-swept zone declined with increasing wind speed, dropping below 5% above 5.4 ms-1. Collision risk could be drastically reduced if nocturnal operation of tall wind turbines would be restricted to wind speeds above 5 ms-1. Such measure should be implemented year-round because T. teniotis remains active in winter. This operational restriction is likely to cause only small energy production losses at these tall wind turbines, although further analyses are needed to assess these losses precisely. [ABSTRACT FROM AUTHOR]

The reasons why bats are coming into contact with wind turbines are not yet well understood. One hypothesis is that bats are attracted to wind turbines and this attraction may be because bats perceive or misperceive the turbines to provide a resource, such as a foraging or roosting site. During post-construction fatality searches at a wind energy facility in the southern Great Plains, U.S., we discovered bat feces near the base of a wind turbine tower, which led us to hypothesize that bats were actively roosting and/or foraging at turbines. Thus over 2 consecutive years, we conducted systematic searches for bat feces on turbines at this site. We collected 72 bat fecal samples from turbines and successfully extracted DNA from 56 samples. All 6 bat species known to be in the area were confirmed and the majority (59%) were identified as Lasiurus borealis ; a species that also comprised the majority of the fatalities (60%) recorded at the site. The presence of bat feces provides further evidence that bats were conducting activities in close proximity to wind turbines. Moreover, feces found in areas such as turbine door slats indicated that bats were using turbines as night or foraging roosts, and further provided evidence that bats were active near the turbines. Future research should therefore aim to identify those features of wind turbines that bats perceive or misperceive as a resource, which in turn may lead to new minimization strategies that effectively reduce bat fatalities at wind farms. [ABSTRACT FROM AUTHOR]

Mitigation of anthropogenic climate change involves deployments of renewable energy worldwide, including wind farms, which can pose a significant collision risk to volant animals. Most studies into the collision risk between species and wind turbines, however, have taken place in industrialized countries. Potential effects for many locations and species therefore remain unclear. To redress this gap, we conducted a systematic literature review of recorded collisions between birds and bats and wind turbines within developed countries. We related collision rate to species-level traits and turbine characteristics to quantify the potential vulnerability of 9538 bird and 888 bat species globally. Avian collision rate was affected by migratory strategy, dispersal distance and habitat associations, and bat collision rates were influenced by dispersal distance. For birds and bats, larger turbine capacity (megawatts) increased collision rates; however, deploying a smaller number of large turbines with greater energy output reduced total collision risk per unit energy output, although bat mortality increased again with the largest turbines. Areas with high concentrations of vulnerable species were also identified, including migration corridors. Our results can therefore guide wind farm design and location to reduce the risk of large-scale animal mortality. This is the first quantitative global assessment of the relative collision vulnerability of species groups with wind turbines, providing valuable guidance for minimizing potentially serious negative impacts on biodiversity. [ABSTRACT FROM AUTHOR]

Conservationists are increasingly concerned about North American bats due to the arrival and spread of the White-nose Syndrome (WNS) disease and mortality associated with wind turbine strikes. To place these novel threats in context for a group of mammals that provides important ecosystem services, we performed the first comprehensive conservation status assessment focusing exclusively on the 45 species occurring in North America north of Mexico. Although most North American bats have large range sizes and large populations, as of 2015, 18–31% of the species were at risk (categorized as having vulnerable, imperiled, or critically imperiled NatureServe conservation statuses) and therefore among the most imperiled terrestrial vertebrates on the continent. Species richness is greatest in the Southwest, but at-risk species were more concentrated in the East, and northern faunas had the highest proportion of at-risk species. Most ecological traits considered, including those characterizing body size, roosting habits, migratory behavior, range size, home range size, population density, and tendency to hibernate, were not strongly associated with conservation status. However, nectarivorous bats tended to be more at risk. The conservation status of bats improved from 1985 to 2000 as human disturbances to roosting sites were reduced, but then declined sharply (7%) by 2015 due principally to threats from WNS and wind energy. Although uncertainty about threats from pollution and climate change remain, past experience shows that when threats are clearly identified and management actions taken, populations can recover. [ABSTRACT FROM AUTHOR]

Monitoring fatalities at wind energy facilities after they have been constructed can provide valuable information regarding impacts of wind power development on wildlife. The objective of this monitoring is to estimate abundance of a super-population of carcasses that entered the area within a designated period of time. By definition, the population is not closed and carcasses can enter as they are killed through collision with turbines, and leave as they are removed by scavengers or decompose to a point where they are not recognizable. In addition, the population is not inherently mobile, but can only change location through some external force. A focus on number of animal carcasses comprising the super-population, combined with peculiar traits that resist classic assumptions, distinguish fatality estimation at wind-power facilities from more classic abundance estimates that can be addressed through mark-recapture techniques or other well-known abundance estimators. We review the available methods to estimate the super-population of carcasses at wind power facilities. We discuss the role of these estimates in determining appropriate levels of minimization and mitigation of impacts to individual species of concern. We discuss the potential to extrapolate these measurements to reflect the cumulative effect of the industry on individual species. Finally, we suggest avenues of research needed to strengthen our understanding of the effect wind power development has, and might have in the future, on wildlife on this continent and worldwide. [ABSTRACT FROM AUTHOR]

Wind power generation is rapidly expanding. Although wind power is a low-carbon source of energy, it can impact negatively birds and bats, either directly through fatality or indirectly by displacement or habitat loss. Pre-construction risk assessment at wind facilities within the United States is usually required only on public lands. When conducted, it generally involves a 3-tier process, with each step leading to more detailed and rigorous surveys. Preliminary site assessment (U.S. Fish and Wildlife Service, Tier 1) is usually conducted remotely and involves evaluation of existing databases and published materials. If potentially at-risk wildlife are present and the developer wishes to continue the development process, then on-site surveys are conducted (Tier 2) to verify the presence of those species and to assess site-specific features (e.g., topography, land cover) that may influence risk from turbines. The next step in the process (Tier 3) involves quantitative or scientific studies to assess the potential risk of the proposed project to wildlife. Typical Tier-3 research may involve acoustic, aural, observational, radar, capture, tracking, or modeling studies, all designed to understand details of risk to specific species or groups of species at the given site. Our review highlights several features lacking from many risk assessments, particularly the paucity of before-and-aftercontrol- impact (BACI) studies involving modeling and a lack of understanding of cumulative effects of wind facilities on wildlife. Both are essential to understand effective designs for pre-construction monitoring and both would help expand risk assessment beyond eagles. [ABSTRACT FROM AUTHOR]

Since 2003, when it was discovered that large numbers of bats were being killed at wind turbines in the eastern United States, our understanding of the impact of wind energy development on bats has increased and consistent patterns of fatality, including seasonality and species composition have become evident. Yet, many questions remain despite the wealth of data collected across numerous post-construction monitoring studies. We synthesized the recent literature to provide an overview of our current understanding of patterns of bat fatalities at wind energy facilities in the United States and Canada. Our understanding of the impact of wind energy development on bats continues to be hindered by inconsistencies among studies and lack of publicly available data. It will be difficult to fully address this complex issue and develop sustainable strategies to reduce the impact of wind turbines on bats and generate wind energy without standardized protocols for field methods, estimation of fatality, and greater cooperation among stakeholders. [ABSTRACT FROM AUTHOR]

Bats represent a substantial contribution to mammalian species diversity and ecosystem processes in North America, including their role in performing important economic service functions. The development and expansion of wind energy facilities is a key threat to bat populations in North America. Dead bats are being found underneath wind turbines across North America, and bat fatalities have been documented at almost all of the wind facilities at which thorough bat surveys have been conducted. The results suggest that thousands of bats may be killed annually at some wind facilities, and recent estimates suggest that hundreds of thousands of bats may be killed annually in the contiguous United States. Here, I use published bat fatality information to derive estimates of the number of bats killed at wind energy facilities in the contiguous United States in 2012 and conclude that over 600,000 bats may have died as a result of interactions with wind turbines. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the editors discuss various reports published within the issue including one on the patterns of collision of bats, another on bat and bird mortality at a single pilot wind turbine in South Africa and another one on data on bird strikes at a New Zealand wind farm.

The article presents the study on the possible theories why bats are susceptible to being killed by operating wind farms in North-Eastern Greece. It states that the fatalities of bat species such as Pipistrellus Pipistrellus, Pipistrellus Pygmaeus, and Hypsugo Savii at wind farms are linked to foraging activity. The fatalities of female bats were found only in spring or in autumn are linked to migration behavior while fatalities of male bats are linked to mating behavior. It also mentions that the bat fatalities caused by collision with turbines may affect the survival of bats.

The article discusses written reports on the effects of wind turbine on bats in northwestern Europe. According to reports, the estimated number of bats killed per turbine annually was relatively low on open farmland and highest at the coast and on forested hills and ridges. Ninety eight percent of species killed belonged to a group adapted for open-air foraging. Meanwhile, 90% of mortality occurred on nights with low wind speeds from July to October. Findings showed that events increased with turbine tower height and rotor diameter. Species other than the open-air suite which are not at risk at wind turbines are still killed occasionally.

Little information exists about finding and managing live bats injured at wind turbines. Our study examines field methods for finding, and successfully treating and releasing, bats and humanely euthanizing those that are terminally injured. Our discovery rate of live and injured bats was greater at turbines searched daily than at turbines searched weekly, and immediate in-field rehydration proved essential in successful treatment. This information can be used to assist in mitigating bat fatalities at wind energy facilities through the timely discovery, treatment, and release of live bats. [ABSTRACT FROM AUTHOR]

Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been made in recent years toward better understanding the problem, the causes of bat fatalities at turbines remain unclear. In this synthesis, we review hypothesized causes of bat fatalities at turbines. Hypotheses of cause fall into 2 general categories--proximate and ultimate. Proximate causes explain the direct means by which bats die at turbines and include collision with towers and rotating blades, and barotrauma. Ultimate causes explain why bats come close to turbines and include 3 general types: random collisions, coincidental collisions, and collisions that result from attraction of bats to turbines. The random collision hypothesis posits that interactions between bats and turbines are random events and that fatalities are representative of the bats present at a site. Coincidental hypotheses posit that certain aspects of bat distribution or behavior put them at risk of collision and include aggregation during migration and seasonal increases in flight activity associated with feeding or mating. A surprising number of attraction hypotheses suggest that bats might be attracted to turbines out of curiosity, misperception, or as potential feeding, roosting, flocking, and mating opportunities. Identifying, prioritizing, and testing hypothesized causes of bat collisions with wind turbines are vital steps toward developing practical solutions to the problem. [ABSTRACT FROM AUTHOR]

Until large numbers of bat fatalities began to be reported at certain North American wind energy facilities, wildlife concerns regarding wind energy focused primarily on bird fatalities. Due in part to mitigation to reduce bird fatalities, bat fatalities now outnumber those of birds. To test one mitigation option aimed at reducing bat fatalities at wind energy facilities, we altered the operational parameters of 21 turbines at a site with high bat fatalities in southwestern Alberta, Canada, during the peak fatality period. By altering when turbine rotors begin turning in low winds, either by changing the wind-speed trigger at which the turbine rotors are allowed to begin turning or by altering blade angles to reduce rotor speed, blades were near motionless in low wind speeds, which resulted in a significant reduction in bat fatalities (by 60.0% or 57.5%, respectively). Although these are promising mitigation techniques, further experiments are needed to assess costs and benefits at other locations. [ABSTRACT FROM AUTHOR]

Wind energy is a rapidly growing sector of the alternative energy industry in North America, and larger, more productive turbines are being installed. However, there are concerns regarding bird and bat fatalities at wind turbines. To assess the influence of turbine size on bird and bat fatalities, we analyzed data from North American wind energy facilities. Diameter of the turbine rotor did not influence the rate of bird or bat fatality. The height of the turbine tower had no effect on bird fatalities per turbine, but bat fatalities increased exponentially with tower height. This suggests that migrating bats fly at lower altitudes than nocturnally migrating birds and that newer, larger turbines are reaching that airspace. Minimizing tower height may help minimize bat fatalities. In addition, while replacing older, smaller turbines with fewer larger ones may reduce bird fatalities per megawatt, it may result in increased numbers of bat fatalities. [ABSTRACT FROM AUTHOR]

Widespread reports of bat fatalities caused by wind turbines have raised concerns about the impacts of wind power development. Reliable estimates of the total number killed and the potential effects on populations are needed, but it is crucial that they be based on sound data. In a recent BioScience article, Hayes (2013) estimated that over 600,000 bats were killed at wind turbines in the United States in 2012. The scientific errors in the analysis are numerous, with the two most serious being that the included sites constituted a convenience sample, not a representative sample, and that the individual site estimates are derived from such different methodologies that they are inherently not comparable. This estimate is almost certainly inaccurate, but whether the actual number is much smaller, much larger, or about the same is uncertain. An accurate estimate of total bat fatality is not currently possible, given the shortcomings of the available data. [ABSTRACT FROM PUBLISHER]

The article discusses the economic aspects of bats in agriculture. According to the authors, insectivorous bat populations have been adversely impacted by white-nose syndrome (WNS), which is disease caused by the fungus Geomyces destructans, and wind turbines. The authors argue that declining bat populations may cost the North American agricultural industry billions of dollars in lost revenue from crop loss. Topics include an overview of the ecological impact of the increased development of wind-power plants and WNS on bat populations in North America and how bats contribute to the economic success of agriculture in the U.S. and Canada, such as by eating millions of pest insects each year that attack crops.

The article discusses wind turbines, which are renewable energy structures used to generate wind power, and complaints that they threaten wildlife and damage neighborhood aesthetics. An example is given of residents on the island of Vinalhaven, Maine who complain that the turbines are loud and ruin the sanctity of the island. According to the author, complaints about wind turbines are increasing, making it difficult for advocates of wind power to build wind farms. Topics include an overview of the environmental impact of wind turbines, such as bird and bat declines resulting from turbine strikes, the problem with radar-interference from wind turbines, and noise pollution caused by the turbines. INSET: Other Siting Problems.

Summary: Bird fatalities at some wind energy facilities around the world have been documented for decades, but the issue of bat fatalities at such facilities — primarily involving migratory species during autumn migration — has been raised relatively recently . Given that echolocating bats detect moving objects better than stationary ones , their relatively high fatality rate is perplexing, and numerous explanations have been proposed . The decompression hypothesis proposes that bats are killed by barotrauma caused by rapid air-pressure reduction near moving turbine blades . Barotrauma involves tissue damage to air-containing structures caused by rapid or excessive pressure change; pulmonary barotrauma is lung damage due to expansion of air in the lungs that is not accommodated by exhalation. We report here the first evidence that barotrauma is the cause of death in a high proportion of bats found at wind energy facilities. We found that 90% of bat fatalities involved internal haemorrhaging consistent with barotrauma, and that direct contact with turbine blades only accounted for about half of the fatalities. Air pressure change at turbine blades is an undetectable hazard and helps explain high bat fatality rates. We suggest that one reason why there are fewer bird than bat fatalities is that the unique respiratory anatomy of birds is less susceptible to barotrauma than that of mammals. [Copyright &y& Elsevier]