According to a team from the USDA Forest Service's
Pacific Southwest Research Station (PSW) in the United States deaths of
migratory bats at wind energy plants have become a 'frequent occurrence'.
Bat migration patterns are poorly understood and the relationship
between deaths at wind energy sites and migratory behaviour are still being
studied, says PSW ecologist Ted Weller.
Mr Weller argues that previous
research has already shown adjusting the operations of turbines can reduce the
number of bats killed by wind turbines but, this strategy has not yet been
widely implemented.
The online tool takes into account bat activity at
different times of the year and a number of environmental conditions, such as
wind direction and speed, air temperature, and moon phase.
Mr Weller and
his research team used devices which detected the bats' echolocation calls, then
linked the presence of bats to the weather conditions measured on-site on a
given night.
Researchers found echolocation detectors placed at 22
meters and 52 meters above ground were more effective at characterizing
migratory bat activity then those located closer to the ground.
Moreover, multiple echolocation detectors were required to accurately
characterize bat activity at the facility. They then built models to predict the
presence of bats based on date and weather variables.
Mr Weller said:
"Increasing the wind speed at which turbines begin to spin and produce energy to
the grid has proven to be an effective way to reduce bat fatalities.
"However, bat activity levels depend on more than just wind speed, our
work demonstrates the use of a decision-making tool that could protect bats when
fatality risk is highest while maximizing energy production on nights with a low
chance of fatalities."