wind turbines

Publication Title: 

Continental-scale, seasonal movements of a heterothermic migratory tree bat

Authors: 
Cryan, P.M., C.A. Stricker, and M.B. Wunder
Publication Date: 
2014
Updated Date (text): 
2013-09-24
Parent Publication Title: 
Ecological Applications
Publication Type: 
Archive number: 
2014/0033 FORT

Pub Abstract: 

Long-distance migration evolved independently in bats and unique migration behaviors are likely, but because of their cryptic lifestyles, many details remain unknown. North American hoary bats (Lasiurus cinereus cinereus) roost in trees year-round and probably migrate farther than any other bats, yet we still lack basic information about their migration patterns and wintering locations or strategies. This information is needed to better understand unprecedented fatality of hoary bats at wind turbines during autumn migration and to determine whether the species could be susceptible to an emerging disease affecting hibernating bats. Our aim was to infer probable seasonal movements of individual hoary bats to better understand their migration and seasonal distribution in North America. We analyzed the stable isotope values of non-exchangeable hydrogen in the keratin of bat hair and combined isotopic results with prior distributional information to derive relative probability density surfaces for the geographic origins of individuals. We then mapped probable directions and distances of seasonal movement. Results indicate that hoary bats summer across broad areas. In addition to assumed latitudinal migration, we uncovered evidence of longitudinal movement by hoary bats from inland summering grounds to coastal regions during autumn and winter. Coastal regions with nonfreezing temperatures may be important wintering areas for hoary bats. Hoary bats migrating through any particular area, such as a wind turbine facility in autumn, are likely to have originated from a broad expanse of summering grounds from which they have traveled in no recognizable order. Better characterizing migration patterns and wintering behaviors of hoary bats sheds light on the evolution of migration and provides context for conserving these migrants.

Publication Title: 

An Integrative and Comparative Approach to Detecting and Understanding Bat Fatalities at Wind Turbines, Fowler Ridge Wind Farm, Indiana, 14 July to 3 October: Final Report

Authors: 
Cryan, P.C., C. Hein, M. Gorresen, R. Diehl, M. Huso, K. Heist, D. Johnson, F. Bonaccorso, and M. Schirmacher
Publication Date: 
2014
Updated Date (text): 
2013-04-25
Parent Publication Title: 
Publication Type: 
Archive number: 
2014/0014 FORT
States: 

Pub Abstract: 
Publication Title: 

An Integrative and Comparative Approach to Detecting and Understanding Bat Fatalities at Wind Turbines, Fowler Ridge Wind Farm, Indiana, 14 July to 3 October, a preliminary report

Authors: 
Cryan, P.C., C. Hein, M. Huso, R. Diehl, D. Johnson, K. Heist, M. Gorresen, and F. Bonaccorso
Publication Date: 
2013
Updated Date (text): 
2013-04-23
Parent Publication Title: 
Publication Type: 
Archive number: 
2013/0021 FORT
States: 

Pub Abstract: 
Publication Title: 

Monitoring behaviors and activity of bats at wind turbines with near infrared videography

Authors: 
Cryan, P.M., P.M. Gorresen, F.J. Bonaccorso, and M.A. Hayes
Publication Date: 
2011
Updated Date (text): 
2011-12-29
Parent Publication Title: 
41st Annual meeting of the North American Society for Bat Research Toronto, Canada 26-30 October, 2011
Publication Type: 
Archive number: 
2011/0143 FORT

Pub Abstract: 
Publication Title: 

Migratory structure and geographic origins of hoary bats (Lasiurus cinereus) inferred from stable isotope analysis

Authors: 
Cryan, P.M., C.A. Stricker, and M.B. Wunder
Publication Date: 
2010
Updated Date (text): 
2012-05-30
Parent Publication Title: 
15th International Bat Research Conference, Prague, Czech Republic 22-27 August 2010
Publication Type: 
Archive number: 
2010/0129 FORT
States: 

Pub Abstract: 
Publication Title: 

Migratory structure and geographic origins of hoary bats (Lasiurus cinereus) inferred from stable isotope analysis

Authors: 
Cryan, P.M., C.A. Stricker, and M.B. Wunder
Publication Date: 
2010
Updated Date (text): 
2011-12-14
Parent Publication Title: 
90th Annual Meeting of the American Society of Mammalogists Laramie, WY 11-15 June 2010
Publication Type: 
Archive number: 
2010/0130 FORT
States: 

Pub Abstract: 
Publication Title: 

Monitoring and researching bat activity at wind turbines with near infrared videography

Authors: 
Gorresen, P.M., P.M. Cryan, and F.J. Bonaccorso
Publication Date: 
2011
Updated Date (text): 
2012-05-03
Parent Publication Title: 
18th Annual Conference of the Wildlife Society Waikoloa, HI 5-10 November 2011
Publication Type: 
Archive number: 
2011/0142 FORT

Pub Abstract: 
Publication Title: 

Bat fatalities at wind turbines: Investigating the causes and consequences

Authors: 
Cryan, P
Publication Date: 
2006
Updated Date (text): 
2010-01-07
Parent Publication Title: 
Publication Type: 
Archive number: 
2006/0156 FORT
States: 

Pub Abstract: 

In the push to develop new forms of sustainable energy, the wind power industry is at the forefront. Turbines that harness the power of wind already serve as effective power sources across the globe, and this proven effectiveness has led to vast increases in the number of turbines currently under construction. The general impact of wind turbines on the environment is likely far less than that of conventional power sources. However, recent evidence shows that certain species of bats are particularly susceptible to mortality from wind turbines. Bats are beneficial consumers of harmful insect pests, and migratory species of bats cross international and interstate boundaries...

Publication Title: 

Behavior of bats at wind turbines

Authors: 
Cryan, P.M., P.M. Gorresen, C.D. Hein, M. Schirmacher, R. Diehl, M. Huso, D.T.S. Hayman, P.D. Fricker, F. Bonaccorso, D.H. Johnson, K. Heist, and D. Dalton
Publication Date: 
2014
Parent Publication Title: 
Proceedings of the National Academy of Sciences of the United States of America
Publication Type: 
Archive number: 
2014/0036 FORT
States: 

Pub Abstract: 

Significance

Bats are dying in unprecedented numbers at wind turbines, but causes of their susceptibility are unknown. Fatalities peak during low-wind conditions in late summer and autumn and primarily involve species that evolved to roost in trees. Common behaviors of “tree bats” might put them at risk, yet the difficulty of observing high-flying nocturnal animals has limited our understanding of their behaviors around tall structures. We used thermal surveillance cameras for, to our knowledge, the first time to observe behaviors of bats at experimentally manipulated wind turbines over several months. We discovered previously undescribed patterns in the ways bats approach and interact with turbines, suggesting behaviors that evolved at tall trees might be the reason why many bats die at wind turbines.

Abstract

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

Publication Title: 

Migration of bats past a remote island offers clues towards the problem of bat fatalities at wind turbines

Authors: 
Cryan, P.M., and A.C. Brown
Publication Date: 
2007
Updated Date (text): 
2012-01-25
Parent Publication Title: 
Biological Conservation
Publication Type: 
Archive number: 
2007/0041 FORT

Pub Abstract: 

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