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Resource Documents: Bats (58 items)

RSSBats

Unless indicated otherwise, documents presented here are not the product of nor are they necessarily endorsed by National Wind Watch. These resource documents are shared here to assist anyone wishing to research the issue of industrial wind power and the impacts of its development. The information should be evaluated by each reader to come to their own conclusions about the many areas of debate. • The copyrights reside with the sources indicated. As part of its noncommercial effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations.


Date added:  April 10, 2021
Colorado, WildlifePrint storyE-mail story

Behavioral patterns of bats at a wind turbine confirm seasonality of fatality risk

Author:  Goldenberg, Shifra; Cryan, Paul; Gorresen, Paulo; and Fingersh, Lee

Abstract: Bat fatalities at wind energy facilities in North America are predominantly comprised of migratory, tree‐dependent species, but it is unclear why these bats are at higher risk. Factors influencing bat susceptibility to wind turbines might be revealed by temporal patterns in their behaviors around these dynamic landscape structures. In northern temperate zones, fatalities occur mostly from July through October, but whether this reflects seasonally variable behaviors, passage of migrants, or some combination of factors remains unknown. In this study, we examined video imagery spanning one year in the state of Colorado in the United States, to characterize patterns of seasonal and nightly variability in bat behavior at a wind turbine. We detected bats on 177 of 306 nights representing approximately 3,800 hr of video and > 2,000 discrete bat events. We observed bats approaching the turbine throughout the night across all months during which bats were observed. Two distinct seasonal peaks of bat activity occurred in July and September, representing 30% and 42% increases in discrete bat events from the preceding months June and August, respectively. Bats exhibited behaviors around the turbine that increased in both diversity and duration in July and September. The peaks in bat events were reflected in chasing and turbine approach behaviors. Many of the bat events involved multiple approaches to the turbine, including when bats were displaced through the air by moving blades. The seasonal and nightly patterns we observed were consistent with the possibility that wind turbines invoke investigative behaviors in bats in late summer and autumn coincident with migration and that bats may return and fly close to wind turbines even after experiencing potentially disruptive stimuli like moving blades. Our results point to the need for a deeper understanding of the seasonality, drivers, and characteristics of bat movement across spatial scales.

Migratory tree bats, like this silver-haired bat (Lasionycteris noctivagans) seen roosting on a tree trunk during autumn, are among the most frequently found dead at wind turbines in North America during late summer and autumn.

Shifra Z. Goldenberg, Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA; Institute for Conservation Research, San Diego Zoo Global, Escondido, CA
Paul M. Cryan, US Geological Survey (USGS), Fort Collins, CO
Paulo Marcos Gorresen, University of Hawaii at Hilo, HI; US Geological Survey Pacific Island Ecosystems Science Center, Hawaii Volcanoes National Park
Lee Jay Fingersh, US Department of Energy, National Renewable Energy Laboratory, National Wind Technology Center, Boulder, CO

Ecology and Evolution, 18 March 2021
doi: 10.1002/ece3.7388

Download original document: “Behavioral patterns of bats at a wind turbine confirm seasonality of fatality risk

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Date added:  September 12, 2019
Oregon, WildlifePrint storyE-mail story

Evidence of region-wide bat population decline from long-term monitoring and bayesian occupancy models with empirically informed priors

Author:  Rodhouse, Thomas; et al.

Abstract—
Strategic conservation efforts for cryptic species, especially bats, are hindered by limited understanding of distribution and population trends. Integrating long‐term encounter surveys with multi‐season occupancy models provides a solution whereby inferences about changing occupancy probabilities and latent changes in abundance can be supported. When harnessed to a bayesian inferential paradigm, this modeling framework offers flexibility for conservation programs that need to update prior model‐based understanding about at‐risk species with new data. This scenario is exemplified by a bat monitoring program in the Pacific Northwestern United States in which results from 8 years of surveys from 2003 to 2010 require updating with new data from 2016 to 2018. The new data were collected after the arrival of bat white‐nose syndrome and expansion of wind power generation, stressors expected to cause population declines in at least two vulnerable species, little brown bat (Myotis lucifugus) and the hoary bat (Lasiurus cinereus). We used multi‐season occupancy models with empirically informed prior distributions drawn from previous occupancy results (2003–2010) to assess evidence of contemporary decline in these two species. Empirically informed priors provided the bridge across the two monitoring periods and increased precision of parameter posterior distributions, but did not alter inferences relative to use of vague priors. We found evidence of region‐wide summertime decline for the hoary bat (λ trend = 0.86 ± 0.10) since 2010, but no evidence of decline for the little brown bat (λ trend = 1.1 ± 0.10). White‐nose syndrome was documented in the region in 2016 and may not yet have caused regional impact to the little brown bat. However, our discovery of hoary bat decline is consistent with the hypothesis that the longer duration and greater geographic extent of the wind energy stressor (collision and barotrauma) have impacted the species. These hypotheses can be evaluated and updated over time within our framework of pre–post impact monitoring and modeling. Our approach provides the foundation for a strategic evidence‐based conservation system and contributes to a growing preponderance of evidence from multiple lines of inquiry that bat species are declining.

Thomas J. Rodhouse, National Park Service and Human and Ecosystem Resiliency and Sustainability Lab, Oregon State University—Cascades, Bend
Rogelio M. Rodriguez, Human and Ecosystem Resiliency and Sustainability Lab, Oregon State University—Cascades, Bend
Katharine M. Banner, Department of Mathematical Sciences, Montana State University, Bozeman
Patricia C. Ormsbee, Willamette National Forest, Springfield, Oregon
Jenny Barnett, Mid‐Columbia River National Wildlife Refuge Complex, U.S. Fish and Wildlife Service, Burbank, Washington
Kathryn M. Irvine, Northern Rocky Mountain Science Center, U.S. Geological Survey, Bozeman, Montana

Ecology and Evolution. 2019;00:1–11.
First published: 11 September 2019
doi: 10.1002/ece3.5612

Download original document: “Evidence of region‐wide bat population decline from long‐term monitoring and bayesian occupancy models with empirically informed priors

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Date added:  January 8, 2019
WildlifePrint storyE-mail story

Evaluating anthropogenic landscape alterations as wildlife hazards, with wind farms as an example

Author:  Law, Peter; and Fuller, Mark

[ABSTRACT]
Anthropogenic alterations to landscape are indicators of potential compromise of that landscape’s ecology. We describe how alterations can be assessed as ‘hazards’ to wildlife through a sequence of three steps: diagnosing the means by which the hazard acts on individual organisms at risk; estimating the fitness cost of the hazard to those individuals and the rate at which that cost occurs; and translating that cost rate into a demographic cost by identifying the relevant demographically-closed population. We exploit the conservation-oriented literature on wind farms to illustrate this conceptual scheme. For wind farms, the third component has received less attention than the first two, which suggests it is the most challenging of the three components. A wind farm provides an example of a ‘spatially localized hazard’, i.e., a discrete alteration of landscape hazardous to some population but of which there are some individuals that do not interact directly with the hazard themselves but nevertheless suffer a reduction in fitness in terms of their contribution to the next generation. Spatially localized hazards are identified via the third component of the scheme and are of particular conservation concern as, by their nature, their depredations on wildlife may be underestimated without an appropriate population-level estimation of the demographic cost of the hazard.

Peter R. Law, Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela University, South Africa
Mark Fuller, Forest and Rangeland Ecosystem Science Center, U.S. Geological Survey, Boise, Idaho

Ecological Indicators 94 (2018) 380–385

Download original document: “Evaluating anthropogenic landscape alterations as wildlife hazards, with wind farms as an example

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Date added:  August 27, 2018
WildlifePrint storyE-mail story

Migratory bats are attracted by red light but not by warm-white light: Implications for the protection of nocturnal migrants

Author:  Voight, Christian; et al.

Abstract:
The replacement of conventional lighting with energy‐saving light emitting diodes (LED) is a worldwide trend, yet its consequences for animals and ecosystems are poorly understood. Strictly nocturnal animals such as bats are particularly sensitive to artificial light at night (ALAN). Past studies have shown that bats, in general, respond to ALAN according to the emitted light color and that migratory bats, in particular, exhibit phototaxis in response to green light. As red and white light is frequently used in outdoor lighting, we asked how migratory bats respond to these wavelength spectra. At a major migration corridor, we recorded the presence of migrating bats based on ultrasonic recorders during 10‐min light‐on/light‐off intervals to red or warm‐white LED, interspersed with dark controls. When the red LED was switched on, we observed an increase in flight activity for Pipistrellus pygmaeus and a trend for a higher activity for Pipistrellus nathusii. As the higher flight activity of bats was not associated with increased feeding, we rule out the possibility that bats foraged at the red LED light. Instead, bats may have flown toward the red LED light source. When exposed to warm‐white LED, general flight activity at the light source did not increase, yet we observed an increased foraging activity directly at the light source compared to the dark control. Our findings highlight a response of migratory bats toward LED light that was dependent on light color. The most parsimonious explanation for the response to red LED is phototaxis and for the response to warm‐white LED foraging. Our findings call for caution in the application of red aviation lighting, particularly at wind turbines, as this light color might attract bats, leading eventually to an increased collision risk of migratory bats at wind turbines.

Christian C. Voigt, Katharina Rehnig, Oliver Lindecke, Gunārs Pētersons

Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany (CCV, KR, OL)
Institute of Biology, Freie Universität Berlin, Germany (CCV, OL)
Faculty of Life Science, University of Vienna, Austria (KR)
Faculty of Veterinary Medicine, Latvia University of Life Sciences and Technologies, Jelgava (GP)

Ecology and Evolution. Published online August 25, 2018. doi: 10.1002/ece3.4400

Download original document: “Migratory bats are attracted by red light but not by warm-white light: Implications for the protection of nocturnal migrants

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