KAB Ecology

Mortality Studies

Although wind farms – one of our best options for clean, sustainable energy are generally accepted to cause the least disturbance to the environment, they can cause significant bird and bat mortality through collisions with the turbine blades. In order to develop a plan to alleviate mortality at wind farms, it is necessary to adequately monitor and generate a reliable estimate of the real mortality rate based on statistical modelling.

Routine carcass monitoring of the turbine pads is the first step in mortality studies. In small wind farms, all turbine pads are included, while in bigger projects, a statistically representative number of turbines are selected. The entire length of the Electric Transmission Lines (ETL) are also included, geography and vegetation permitting.

To arrive at an estimation of the actualy rates of fatality, the second step is determining the variables which effect how many carcasses are detected by the surveyors in the first step.

  • A greater fraction of animals fall outside of the turbine pad rather than the inside and cannot be found in dense vegetation (Density Weighted Proportions, DWP).
  • Surveyors have differing efficiency levels when it comes to finding carcasses. Even the most skilled surveyor cannot detect all carcasses on the ground (Searcher Efficiency, SE).
  • Most carcasses are removed by scavenger animals, such as foxes, dogs, crows and even wasps (Carcass Persistancy, CP).

Carcass Counts + Determining Variables + Modelling = Mortality Estimation

The third and last step is inputting the observed carcasses and the three variables into a model for mortality estimation. Our data and the variables are channeled into a robust statistical suite and results in a reliable estimation of mortality rate at the project site. The model can be further refined for weekly intervals and by turbine.