Behavior of Bats at Wind Turbines

» Posted by on Oct 15, 2014 in Environmental | Comments Off on Behavior of Bats at Wind Turbines

The following research was carried out by many individuals. The  paper from which the summary below was taken was edited by James Brown of the University of New Mexico.  I think it is germaine because of the push lately for using non greenhouse gas emitting sources for our energy requirements.

Wind turbines cause many bat fatalities. Some of these fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with this risk, bats were monitored at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012.  Thermal cameras and other methods were used for this monitoring. Bats were observed on 993 occasions.  Various behaviours including close approaches, flight loops and dives, hovering, and chases were observed. Most bats altered course toward turbines during these observations. Based on these new observations, they tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. They found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward 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 behaviours that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

Other hypotheses for bird mortality near wind turbines are that turbines heat the air that passes through them which then attracts insects which in turn attract birds that results in their death.  Let’s ensure data like this is used when deciding on a location for a wind farm.

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