Draft National Wind Farm Development Guidelines - July 2010

of mortalities, are both the number of individuals that might interact with turbines and the
estimated number of their flights that are at risk of collision. An overview of collision risk
modelling used in Australia is provided in Smales (2006).
Behavioural responses to wind turbines
Bird and/or bat utilisation studies within an operational wind farm must be undertaken
according to protocols that permit results to be compared directly with those obtained
prior to construction. On the basis of such Before – After investigations any response of birds
or bats to the presence of the wind farm may be evaluated. This will include responses to
loss or modification of habitat and any disturbance caused by proximity to turbines.
Where applicable, targeted studies should be designed to obtain data on the rates at
which relevant species of birds and bats avoid collisions when flying in the presence of
turbines. This will require documentation of how birds and/or bats behave when flying
within a turbine array. Techniques outlined elsewhere here for recording bird and bat flights
can be applied for this purpose.
Documenting collision fatalities
The reason for determining the species and numbers of individuals killed by turbine
collisions is to ascertain any effects on the functioning and maintenance of key species’
populations. In order to achieve that aim, the number of fatalities should be evaluated
against results of PVA or PBR analysis undertaken as part of the assessment process.
Determining how many birds or bats are killed is not an objective of itself and it is of
minimal scientific value to simply record carcasses noticed during the course of other
activities on the site. A program for monitoring fatalities should be designed according to
sound statistical research principles. Searches for dead birds and bats around turbines are
likely to be required and it is essential that these are undertaken to a rigorous regime
design that accounts for variables in detectability of carcasses. Practical considerations
and limits on detectability will necessitate that the study is designed to obtain an index of
mortalities rather than an absolute count.
Trials to determine carcass scavenging rates and capacity to detect carcasses should be
undertaken at the site. It is important that statistical power analyses are applied to assess
the efficacy of trials after they have been run. Scavenger exclusion fencing around some
turbines may reduce scavenging rates and thus increase capacity for carcass detection.
The use of trained dogs may be considered as an aid to detecting carcasses. If trials
demonstrate that detection of carcasses is not able to be effectively achieved then the
situation should be reviewed in conjunction with the relevant authorities.
The monitoring strategy employed should be focussed on key species of interest,
scavenging rates for the site and the capacity of techniques and observers to detect
carcasses. It is important to employ techniques and parameters that are specifically
tailored to the site and relevant species. Meta-data relevant to collisions must be
documented in order to determine patterns or trends that might exist. These will include
information about the turbine involved and weather and other environmental conditions
when a collision is believed to have occurred.
D.7.2 Specific investigation methods for bats
Guidance for methods of investigating bats at wind farm sites is provided for an Australian
context in Lumsden (2007). Ministry of Natural Resources, Ontario (2007) is another valuable
resource for this purpose. The following discussion is primarily focussed on bat taxa other
than fruit bats. It offers an outline of methods and techniques that may be applicable but
sources such as those cited are recommended for the further detail they provide.
Methods for detection of insectivorous bats that have been used to-date in Australia do
not permit quantification of bat utilisation of sites in measures such as numbers of
individuals or bat flights per unit time, with the precision required for analytical assessments
like collision risk modelling and Population Viability Analysis. For the present, it will generally
Draft National Wind Farm Development Guidelines – 2 July 2010 Page 139