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At least 55 records · Page 3Linked to original sources
USGS2021

Demographic and potential biological removal models identify raptor species sensitive to current and future wind energy

A central challenge in applied ecology is understanding the effect of anthropogenic fatalities on wildlife populations and predicting which populations may be particularly vulnerable and in greatest need of management attention. We used 3 approaches to investigate potential effects of fatalities from collisions with wind turbines on 14 raptor species for both current (106 GW) and anticipated future (241 GW) levels of installed wind energy capacity in the United States. Our goals were to identify species at relatively high vs low risk of experiencing population declines from turbine collisions and to also compare results generated from these approaches. Two of the approaches used a calculated turbine-caused mortality rate to decrement population growth, where population trends were derived either from the North American Breeding Bird Survey or a matrix model parameterized from literature-derived demographic values. The third approach was potential biological removal, which estimates the number of fatalities that allow a population to reach and maintain its optimal sustainable population set by management concerns. Different results among the methods reveal substantial gaps in knowledge and uncertainty in both demographic parameters and species-specific estimates of fatalities from wind turbines. Our results suggest that, of the 14 species studied, those with relatively higher potential of population-level impacts from wind turbine collisions included barn owl, ferruginous hawk, golden eagle, American kestrel, and red-tailed hawk. Burrowing owl, Cooper’s hawk, great horned owl, northern harrier, turkey vulture, and osprey had a relatively lower potential for population impacts, and results were not easily interpretable for merlin, prairie falcon, and Swainson’s hawk. Projections of current levels of fatalities to future wind energy scenarios at 241 GW of installed capacity suggest some species could experience population declines because of turbine collisions. Populations of those species may benefit from research to identify tools to prevent or reduce raptor collisions with wind turbines.

Ecosphere↗
USGS2015

Effects of wind-energy facilities on grassland bird distributions

The contribution of renewable energy to meet worldwide demand continues to grow. Wind energy is one of the fastest growing renewable sectors, but new wind facilities are often placed in prime wildlife habitat. Long-term studies that incorporate a rigorous statistical design to evaluate the effects of wind facilities on wildlife are rare. We conducted a before-after-control-impact (BACI) assessment to determine if wind facilities placed in native mixed-grass prairies displaced breeding grassland birds. During 2003–2012, we monitored changes in bird density in 3 study areas in North Dakota and South Dakota (U.S.A.). We examined whether displacement or attraction occurred 1 year after construction (immediate effect) and the average displacement or attraction 2–5 years after construction (delayed effect). We tested for these effects overall and within distance bands of 100, 200, 300, and >300 m from turbines. We observed displacement for 7 of 9 species. One species was unaffected by wind facilities and one species exhibited attraction. Displacement and attraction generally occurred within 100 m and often extended up to 300 m. In a few instances, displacement extended beyond 300 m. Displacement and attraction occurred 1 year after construction and persisted at least 5 years. Our research provides a framework for applying a BACI design to displacement studies and highlights the erroneous conclusions that can be made without the benefit of adopting such a design. More broadly, species-specific behaviors can be used to inform management decisions about turbine placement and the potential impact to individual species. Additionally, the avoidance distance metrics we estimated can facilitate future development of models evaluating impacts of wind facilities under differing land-use scenarios.

North Dakota, South Dakota↗
USGS2024

Accounting for the fraction of carcasses outside the searched area in the estimation of bird and bat fatalities at wind energy facilities

Accurate estimation of bird and bat mortality at wind energy facilities requires accounting for carcasses that lie outside the search plots because they lie beyond the search radius or in areas within the search radius that remain unsearched due to sub-optimal search conditions such as thick vegetation, rough or dangerous ground, water, or restricted access to the land. However, carcass density is not constant around a turbine and the fraction of carcasses within the unsearched area can vary greatly depending on where the area lies relative to the turbine. The density-weighted proportion approach takes into account the changing density of carcasses around turbines to estimate the fraction of carcasses lying in unsearched areas (dwp). It involves tallying the carcasses found in concentric rings centered at the turbine, fitting a curve to the carcass densities in the rings, and dividing the integral of the curve over the area searched by the integral over the total area. Accounting for unsearched area presents special difficulties such as extrapolation beyond the search radius, spatial prediction, and model selection, which are frequently ignored or under-appreciated, potentially resulting in substantial estimation errors. A powerful new R software package (dwp) is available to perform the calculations, given the distances at which carcasses were found from turbines and a map of the searched area used to discern the fraction of the ground searched at each distance. If all ground within a given search radius has been searched, the map is simply the search radius. For more complicated search plots, other kinds of maps may be used: R polygons for plots that can be readily delineated into searched and not-searched areas (for example, searches restricted to access roads and turbine pads), GIS shape files for complicated search patterns (for example, non-uniform vegetation or ground texture resulting in spatially varying search conditions), or raster files for complicated search patterns coupled with carcass spatial distribution that depends on both distance and direction from turbines. This study discusses estimation and interpretation of dwp in the context of several realistic examples; provides guidance for use of the dwp software for doing the analyses; and addresses questions of extrapolation, spatial prediction, and model selection.

Techniques and Methods↗
USGS2013

Golden eagle records from the Midwinter Bald Eagle Survey: information for wind energy management and planning

The purpose of this Data Series report is to provide the occasions, locations, and counts when golden eagles were recorded during the annual Midwinter Bald Eagle Surveys. Golden eagles (Aquila chrysaetos) are protected by Federal statutes including the Bald and Golden Eagle Protection Act (BGEPA) (16 USC 668-668c) and the Migratory Bird Treaty Act (MBTA) (16 USC 703-12). The U.S. Fish and Wildlife Service (Service) manages golden eagles with the goal of maintaining stable or increasing breeding populations (U.S. Fish and Wildlife Service, 2009). Development for the generation of electricity from wind turbines is occurring in much of the range of the golden eagle in the western United States. Development could threaten population stability because golden eagles might be disturbed by construction and operation of facilities and they are vulnerable to mortality from collisions with wind turbines (Smallwood and Thelander, 2008). Therefore, the Service has proposed a process by which wind energy developers can collect information that could lead to Eagle Conservation Plans (ECP), mitigation, and permitting that allow for golden eagle management in areas of wind energy development (U.S. Fish and Wildlife Service, 2011). The Service recommends that ECP be developed in stages, and the first stage is to learn if golden eagles occur at the landscape level where potential wind facilities might be located. Information about where eagles occur can be obtained from technical literature, agency files, and other sources of information including on-line biological databases. The broad North American distribution of golden eagles is known, but there is a paucity of readily available information about intermediate geographic scales and site-specific scales, especially during the winter season (Kochert and others, 2002).

Data Series↗
USGS2016

Wintering Sandhill Crane exposure to wind energy development in the central and southern Great Plains, USA

Numerous wind energy projects have been constructed in the central and southern Great Plains, USA, the main wintering area for midcontinental Sandhill Cranes (Grus canadensis). In an initial assessment of the potential risks of wind towers to cranes, we estimated spatial overlap, investigated potential avoidance behavior, and determined the habitat associations of cranes. We used data from cranes marked with platform transmitting terminals (PTTs) with and without global positioning system (GPS) capabilities. We estimated the wintering distributions of PTT-marked cranes prior to the construction of wind towers, which we compared with current tower locations. Based on this analysis, we found 7% spatial overlap between the distributions of cranes and towers. When we looked at individually marked cranes, we found that 52% would have occurred within 10 km of a tower at some point during winter. Using data from cranes marked after tower construction, we found a potential indication of avoidance behavior, whereby GPS-marked cranes generally used areas slightly more distant from existing wind towers than would be expected by chance. Results from a habitat selection model suggested that distances between crane locations and towers may have been driven more by habitat selection than by avoidance, as most wind towers were constructed in locations not often selected by wintering cranes. Our findings of modest regional overlap and that few towers have been placed in preferred crane habitat suggest that the current distribution of wind towers may be of low risk to the continued persistence of wintering midcontinental Sandhill Cranes in the central and southern Great Plains.

Kansas, New Mexico, Oklahoma, Texas↗
USGS2015

Golden Eagle mortality at a utility-scale wind energy facility near Palm Springs, California

Golden Eagle ( Aquila chrysaetos ) mortality associated with wind energy turbines and infrastructure is under-reported and weakly substantiated in the published literature. I report two cases of mortality at a utility-scale renewable energy facility near Palm Springs, California. The facility has been in operation since 1984 and included 460 65KW turbines mounted on 24.4 m or 42.7 m lattice-style towers with 8 m rotor diameters. One mortality event involved a juvenile eagle that was struck and killed by a spinning turbine blade on 31 August, 1995. The tower was 24.4 m high. The other involved an immature female that was struck by a spinning blade on another 24.4 m tower on 17 April, 1997 and was later euthanized due to the extent of internal injuries. Other raptor mortalities incidentally observed at the site, and likely attributable to turbines, included three Red-tailed Hawks ( Buteo jamaicensis ) found near turbines.

California↗
USGS2016

Wind energy development: Methods to assess bird and bat fatality rates post-construction

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.

Human-Wildlife Interactions↗
USGS2015

Seasonally-dynamic presence-only species distribution models for a cryptic migratory bat impacted by wind energy development

Understanding seasonal distribution and movement patterns of animals that migrate long distances is an essential part of monitoring and conserving their populations. Compared to migratory birds and other more conspicuous migrants, we know very little about the movement patterns of many migratory bats. Hoary bats ( Lasiurus cinereus ), a cryptic, wide-ranging, long-distance migrant, comprise a substantial proportion of the tens to hundreds of thousands of bat fatalities estimated to occur each year at wind turbines in North America. We created seasonally-dynamic species distribution models (SDMs) from 2,753 museum occurrence records collected over five decades in North America to better understand the seasonal geographic distributions of hoary bats. We used 5 SDM approaches: logistic regression, multivariate adaptive regression splines, boosted regression trees, random forest, and maximum entropy and consolidated outputs to generate ensemble maps. These maps represent the first formal hypotheses for sex- and season-specific hoary bat distributions. Our results suggest that North American hoary bats winter in regions with relatively long growing seasons where temperatures are moderated by proximity to oceans, and then move to the continental interior for the summer. SDMs suggested that hoary bats are most broadly distributed in autumn—the season when they are most susceptible to mortality from wind turbines; this season contains the greatest overlap between potentially suitable habitat and wind energy facilities. Comparing wind-turbine fatality data to model outputs could test many predictions, such as ‘risk from turbines is highest in habitats between hoary bat summering and wintering grounds’. Although future field studies are needed to validate the SDMs, this study generated well-justified and testable hypotheses of hoary bat migration patterns and seasonal distribution.

PLoS ONE↗
USGS2013

Nest guarding by female Agassiz's desert tortoise (Gopherus agassizii) at a wind-energy facility near Palm Springs, California

We observed behavior consistent with nest-guarding in Agassiz's desert tortoise (Gopherus agassizii) at two nests in a large wind-energy-generation facility near Palm Springs, California, locally known as the Mesa Wind Farm. As researchers approached the nests, female desert tortoises moved to the entrance of their burrows and positioned themselves sideways, directly over their nests. One female stretched her limbs outward and wedged herself into the burrow (her plastron directly above the nest). Guarding of nests is rarely observed in Agassiz's desert tortoise but can occur as a result of attempted predation on eggs by Gila monsters (Heloderma suspectum) or in direct response to the perceived threat posed by researchers. This is the first report of nest-guarding for G. agassizii in the Sonoran Desert ecosystem of California.

California↗
USGS2016

Avian fatalities at wind energy facilities in North America: A comparison of recent approaches

Three recent publications have estimated the number of birds killed each year by wind energy facilities at 2012 build-out levels in the United States. The 3 publications differ in scope, methodology, and resulting estimates. We compare and contrast characteristics of the approaches used in the publications. In addition, we describe decisions made in obtaining the estimates that were produced. Despite variation in the 3 approaches, resulting estimates were reasonably similar; about a quarter- to a half-million birds are killed per year by colliding with wind turbines.

Human-Wildlife Interactions↗
USGS2018

Collision and displacement vulnerability to offshore wind energy infrastructure among marine birds of the Pacific Outer Continental Shelf

Marine birds are vulnerable to collision with and displacement by offshore wind energy infrastructure (OWEI). Here we present the first assessment of marine bird vulnerability to potential OWEI in the California Current System portion of the U.S. Pacific Outer Continental Shelf (POCS). Using population size, demography, life history, flight heights, and avoidance behavior for 62 seabird and 19 marine water bird species that occur in the POCS, we present and apply equations to calculate Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability to OWEI for each species. Species with greatest Population vulnerability included those listed as species of concern (e.g., Least Tern [ Sternula antillarum ], Marbled Murrelet [ Brachyramphus marmoratus ], Pink-footed Shearwater [ Puffinus creatopus ]) and resident year-round species with small population sizes (e.g., Ashy Storm-Petrel [ Oceanodroma homochroa ], Brandt's Cormorant [ Phalacrocorax penicillatus ], and Brown Pelican [ Pelecanus occidentalis ]). Species groups with the greatest Collision Vulnerability included jaegers/skuas, pelicans, terns and gulls that spend significant amounts of time flying at rotor sweep zone height and don't show macro-avoidance behavior (avoidance of entire OWEI area). Species groups with the greatest Displacement Vulnerability show high macro-avoidance behavior and low habitat flexibility and included loons, grebes, sea ducks, and alcids. Using at-sea survey data from the southern POCS, we combined species-specific vulnerabilities described above with at-sea species densities to assess vulnerabilities spatially. Spatial vulnerability densities were greatest in areas with high species densities (e.g., near-shore areas) and locations where species with high vulnerability were found in abundance. Our vulnerability assessment helps understand and minimize potential impacts of OWEI infrastructure on marine birds in the POCS and could inform management decisions.

Journal of Environmental Management↗
USGS2021

Relative energy production determines effect of repowering on wildlife mortality at wind energy facilities

Reduction in wildlife mortality is often cited as a potential advantage to repowering wind facilities, that is, replacing smaller, lower capacity, closely spaced turbines, with larger, higher capacity ones, more widely spaced. Wildlife mortality rates, however, are affected by more than just size and spacing of turbines, varying with turbine operation, seasonal and daily weather and habitat, all of which can confound our ability to accurately measure the effect of repowering on wildlife mortality rates. We investigated the effect of repowering on wildlife mortality rates in a study conducted near Palm Springs, CA. We controlled for confounding effects of weather and habitat by measuring turbine‐caused wildlife mortality rates over a range of turbine sizes and spacing, all within the same time period, habitat and local weather conditions. We controlled for differences in turbine operation by standardizing mortality rate per unit energy produced. We found that avian and bat mortality rate was constant per unit of energy produced, across all sizes and spacings of turbines. Synthesis and applications . In the context of repowering a wind facility, our results suggest that the relative amount of energy produced, rather than simply the size, spacing or nameplate capacity of the replacement turbines, determines the relative rate of mortality prior to and after repowering. Consequently, in a given location, newer turbines would be expected to be less harmful to wildlife only if they produced less energy than the older models they replace. The implications are far‐reaching as 18% of US and 8% of world‐wide wind power capacity will likely be considered for repowering within ~5 years.

California↗
USGS2011

Long-term post-fire effects on spatial ecology and reproductive output of female Agassiz’s desert tortoises ( Gopherus agassizii ) at a wind energy facility near Palm Springs, California, USA

We studied the long-term response of a cohort of eight female Agassiz’s desert tortoises ( Gopherus agassizii ) during the first 15 years following a large fire at a wind energy generation facility near Palm Springs, California, USA. The fire burned a significant portion of the study site in 1995. Tortoise activity areas were mapped using minimum convex polygons for a proximate post-fire interval from 1997 to 2000, and a long-term post-fire interval from 2009 to 2010. In addition, we measured the annual reproductive output of eggs each year and monitored the body condition of tortoises over time. One adult female tortoise was killed by the fire and five tortoises bore exposure scars that were not fatal. Despite predictions that tortoises would make the short-distance movements from burned to nearby unburned habitats, most activity areas and their centroids remained in burned areas for the duration of the study. The percentage of activity area burned did not differ significantly between the two monitoring periods. Annual reproductive output and measures of body condition remained statistically similar throughout the monitoring period. Despite changes in plant composition, conditions at this site appeared to be suitable for survival of tortoises following a major fire. High productivity at the site may have buffered tortoises from the adverse impacts of fire if they were not killed outright. Tortoise populations at less productive desert sites may not have adequate resources to sustain normal activity areas, reproductive output, and body conditions following fire.

California↗
USGS2012

Female Agassiz’s desert tortoise activity at a wind energy facility in southern California: The influence of an El Niño event

We compared spring-summer activity of adult female Agassiz’s Desert Tortoises ( Gopherus agassizii ) among three consecutive years (1997, 1998, and 1999) that differed dramatically in winter rainfall and annual plant production at a wind energy facility in the Sonoran Desert of southern California. Winter rainfall was approximately 71%, 190%, and 17% of the long-term average (October-March = 114 mm) for this area in water years (WY) 1997, 1998, and 1999, respectively. The substantial precipitation caused by an El Niño Southern Oscillation (ENSO) event in WY 1998 produced a generous annual food plant supply (138.2 g dry biomass/ m 2 ) in the spring. Primary production of winter annuals during below average rainfall years (WY 1997 and WY 1999) was reduced to 98.3 and 0.2 g/m 2 , respectively. Mean rates of movement and mean body condition indices (mass/length) did not differ significantly among the years. The drought year following ENSO (WY 1999) was statistically similar to ENSO in every other measured value, while WY 1997 (end of a two year drought) was statistically different from ENSO using activity area, minimum number of burrows used, and percentage of non-movements. Our data suggest that female G. agassizii activity can be influenced by environmental conditions in previous years.

California↗
USGS2014

Nest site characteristics, nesting movements, and lack of long-term nest site fidelity in Agassiz's desert tortoises at a wind energy facility in southern California

Nest site selection has important consequences for maternal and offspring survival and fitness. Females of some species return to the same nesting areas year after year. We studied nest site characteristics, fidelity, and daily pre-nesting movements in a population of Agassiz’s desert tortoises (Gopherus agassizii) at a wind energy facility in southern California during two field seasons separated by over a decade. No females returned to the same exact nest site within or between years but several nested in the same general area. However, distances between first and second clutches within a year (2000) were not significantly different from distances between nests among years (2000 and 2011) for a small sample of females, suggesting some degree of fidelity within their normal activity areas. Environmental attributes of nest sites did not differ significantly among females but did among years due largely to changes in perennial plant structure as a result of multiple fires. Daily pre-nesting distances moved by females decreased consistently from the time shelled eggs were first visible in X-radiographs until oviposition, again suggesting some degree of nest site selection. Tortoises appear to select nest sites that are within their long-term activity areas, inside the climate-moderated confines of one of their self-constructed burrows, and specifically, at a depth in the burrow that minimizes exposure of eggs and embryos to lethal incubation temperatures. Nesting in “climate-controlled” burrows and nest guarding by females relaxes some of the constraints that drive nest site selection in other oviparous species.

California↗
USGS2015

Statistical guidelines for assessing marine avian hotspots and coldspots: A case study on wind energy development in the U.S. Atlantic Ocean

Estimating patterns of habitat use is challenging for marine avian species because seabirds tend to aggregate in large groups and it can be difficult to locate both individuals and groups in vast marine environments. We developed an approach to estimate the statistical power of discrete survey events to identify species-specific hotspots and coldspots of long-term seabird abundance in marine environments. We illustrate our approach using historical seabird data from survey transects in the U.S. Atlantic Ocean Outer Continental Shelf (OCS), an area that has been divided into “lease blocks” for proposed offshore wind energy development. For our power analysis, we examined whether discrete lease blocks within the region could be defined as hotspots (3 × mean abundance in the OCS) or coldspots (1/3 ×) for individual species within a given season. For each of 74 species/season combinations, we determined which of eight candidate statistical distributions (ranging in their degree of skewedness) best fit the count data. We then used the selected distribution and estimates of regional prevalence to calculate and map statistical power to detect hotspots and coldspots, and estimate the p -value from Monte Carlo significance tests that specific lease blocks are in fact hotspots or coldspots relative to regional average abundance. The power to detect species-specific hotspots was higher than that of coldspots for most species because species-specific prevalence was relatively low (mean: 0.111; SD: 0.110). The number of surveys required for adequate power (> 0.6) was large for most species (tens to hundreds) using this hotspot definition. Regulators may need to accept higher proportional effect sizes, combine species into groups, and/or broaden the spatial scale by combining lease blocks in order to determine optimal placement of wind farms. Our power analysis approach provides a general framework for both retrospective analyses and future avian survey design and is applicable to a broad range of research and conservation problems.

U.S. Atlantic Ocean Outer Continental Shelf↗
USGS2014

A comment on "bats killed in large numbers at United States wind energy facilities"

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.

BioScience↗
USGS2016

Wind energy development: Methods for assessing risks to birds and bats pre-construction

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-after-control- 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.

Human-Wildlife Interactions↗