A new physics-based model for guiding bat carcass surveys at wind turbines

Power generation from wind energy is one of the major contributors to the strategy to reduce the negative impacts of climate change by reducing greenhouse gas emissions from fossil fuel use. Four-to five-hold expansion of land-based wind energy by the year 2050 is required to minimize the temperature increases and reduce the climate change risk. Wind power, like many other power sources, can have adverse impacts on wildlife. One of most evident impact of wind facility installations is collision fatalities of bats with turbine blades. Population-level impacts on the migratory tree bats are a matter of concern. For evaluating the impact of growing number of wind energy capacities on bat population, the estimates of the regional and cumulative bat fatalities in wind farms are required.

In this work, we propose a physics-based model to guide carcass survey efforts in a wind farm to find the accurate estimates of bat fatalities. The drag characteristics of bat carcasses were estimated by analyzing the fall position data obtained from high-speed imaging of carcass drop experiments. A 3-D ballistics model was introduced to check the sensitivity of bat ground impact patterns with respect to turbine geometry, bat physical properties, wind speed, and turbine rotation rate. Repeated random sampling was performed using input parameter distributions of the 3-D ballistics model to compute bat ground impact patterns for the autumn migration season of bats.