Draft National Wind Farm Development Guidelines - July 2010

equisite to undertaking PVA is a sound understanding of the demography
of the population under consideration.
Potential Biological
Removal assessment
(PBR)
Qualitative
Quantitative
Taxon (plural: taxa)
Utilisation
A process to model the annual number of additional mortalities that a
population can sustain (e.g. Dillingham & Fletcher 2008). Simpler, but
potentially less sensitive and robust than PVA, PBR can function with less
demographic information than PVA. Requisite inputs are just estimated
population size, maximum annual recruitment rate and a number of
additional mortalities - in this context, additional mortalities due to the
wind farm.
Relating to or based on the quality or character of something, as
opposed to its size or numerical quantity.
Relating to, measured, or measurable by size or numerical quantity.
A name designating a group of biologically related organisms as a
taxonomic unit (e.g. species, genus).
The use of an area by a particular species expressed as quantified activity
(for the purposes of collision risk, the number of flights) per unit of time and
space.
D.7 Technical discussion of key concepts/issues
As outlined previously, it is not the intent of these Guidelines to be prescriptive about
methodologies. Flexibility in specifics of research design and technologies that may be
used to obtain the requisite data is vital to allow for particulars of taxa and sites and to
permit adaptability to emerging technologies and techniques. The most important aspect
is that bird and bat utilisation of various wind farm sites is quantified to standard measures
and that appropriate statistical approaches and analyses are used. Peer review of study
design and of its results should be provided by individuals with relevant expertise and
knowledge of the standards to be achieved.
This section is provided as an adjunct to the preceding discussion of assessment processes
to provide examples of methods that may be employed for monitoring and collection of
birds and bat data for wind farm assessments and as a guide to some further sources of
relevant information.
The first section may be applicable to birds and/or bats while the second section is specific
to bats other than fruit bats (Pteropodidae). In a number of respects relevant to
assessment of wind farms, the flight behaviours of fruit bats are more similar to those of
crepuscular and nocturnal birds than they are to other bat taxa. It may be feasible to
obtain information for fruit bats that permits risk to be assessed in a fashion similar to
assessments for birds. This has been achieved for a wind farm development in Fiji (Smales
2005).
D.7.1 Potential investigation & assessment methods
Determining bird and bat utilisation rates
Estimated annual number of flights by key species at risk of collision should be extrapolated
from samples documenting numbers of flights within rotor-swept-height per unit time.
Standard and replicable timed counts of bird flights should be documented from a series
of locations across the site. The basis for this methodology is the Point Count (Reynolds et
al. 1980). Standard texts outline the fundamentals and limitations of this technique (e.g.
Bibby et al. 2000). Note that the technique is adapted from its original purpose of counting
numbers of birds to the counting of bird movements. Locations of count sites should be
selected to be representative of turbine sites. Counts should be made in all seasons in
which the species may be present and at all times of the daily cycle and conditions in
which birds might fly. Statistical power analysis is applicable to determine the appropriate
number of count locations and of counts that will adequately detect and document
variables of bird flights for a given site. Records should be collected that document the
height above ground and horizontal distance of a bird from the observer at the instant
Draft National Wind Farm Development Guidelines – 2 July 2010 Page 137