Wind energy is a significant component of the Victorian government’s commitment to renewable energy. Assessment of potential impacts on birds and bats due to collisions with turbines is now routinely undertaken at operating wind farms, and this includes post-construction mortality monitoring. Monitoring programs vary considerably between wind farms in their objectives and design, and in the intensity, frequency and duration of monitoring. Bird and bat carcasses that are found are documented and, to estimate the total numbers of mortalities that are likely to have occurred on a wind farm, correction factors are developed to factor in the level of sampling and site-specific detectability issues. However, despite many years of monitoring, the accuracy of such estimates remains unclear, and it is not yet known whether turbine collisions are having a significant impact on populations of birds and bats. Therefore, it is timely to conduct a review of the postconstruction mortality monitoring that has been undertaken to date, to assess what conclusions can be drawn from the available data, and to develop options for improvements in the future.
The specific aims of this review are:
- to examine the existing post-construction mortality monitoring data to evaluate whether these data are adequate to estimate annual mortalities of birds and bats at wind farms;
- to generate a list of all the species known to have been killed by collisions with turbines at wind farms;
- to discuss possible approaches for assessing the cumulative and population-level impacts of multiple wind farms across the landscape;
- to develop options for future post-construction monitoring for wind farms and to discuss their advantages and disadvantages; and
- to identify key knowledge gaps that, if filled, would enable greater confidence in mortality assessments and in estimates of cumulative and population-level impacts.