Forthbank Wind Energy Development - Partnerships for Renewables

Forthbank Wind Energy Development
Collision Risk Modelling
12.3.41 Of the target species recorded during the flight activity surveys, at least 3 statistically
independent flight events (see Appendix 12.1) which might be at risk of turbine collision within
the wind energy development per year were recorded for 10 species (Table 12.15). These
included seven qualifying wetland bird species of the Firth of Forth SPA, two non-qualifying
wetland species, and one raptor species. There was considered to be insufficient information
(i.e. fewer than 3 statistically independent flight events) to enable robust collision risk
predictions for these species however, it follows that the infrequency of “at risk” flight activity
for the other target species means that their risk of turbine collisions should be low.
12.3.42 The flight activity data for the 10 species was extrapolated, for each period of interest, to give
estimates of their total flights through the Risk Window or Risk Volume, respectively 23 . These
totals were then entered into a collision risk model to generate estimates of the frequency of
turbine collisions for each species during the period of interest. Tables 12.1.11 to 12.1.24,
Appendix 12.1 detail each stage of the collision modelling process. Collision risk modelling
estimates the number of collisions that would occur if birds take no avoiding action to fly
around turbines. An avoidance rate is then applied based on available evidence for the
tendency of birds to take avoiding action, for example an avoidance rate of 99% indicates that
during 99 out of 100 flights a bird of a given species would be expected to take avoiding action
when flying towards a wind turbine. Results of the collision risk modelling for the proposed
wind energy development are presented for a range of avoidance rates (Table 12.16). Based
on the most recent guidance from SNH (September 2010) 24 , the recommended avoidance rate
is 98% for most bird species (a change from previous SNH advice that a default avoidance rate
of 95% should be applied), and 99% for geese.
Table 12.16 Predicted Collision Risk Mortality for Target Species with “At Risk” Flights
at Forthbank
Species (and season) Predicted collision risk mortality rates (birds per year) under different avoidance
rates (mortality rates in bold represent the avoidance rate recommended by SNH 24 for
a given species)
No avoidance 95% 98% 99%
SPA Qualifying Species
Cormorant (annual) 11.73 0.59 0.23 0.12
Curlew (annual) 40.58 2.03 0.81 0.41
Lapwing: breeding 16.15 0.81 0.32 0.16
Lapwing: non-breeding 25.10 1.26 0.50 0.25
Mallard: breeding 36.10 1.81 0.72 0.36
Mallard: non-breeding 89.90 4.49 1.80 0.90
Pink-footed goose (annual) 5485 - - 55
Shelduck: breeding 3.6 0.18 0.07 0.04
Shelduck: non-breeding 14.6 0.73 0.29 0.15
Sandwich tern 12.0 0.60 0.24 0.12
Non-SPA Qualifying Wetland Bird Species
Greylag goose 31 - - 0.31
Tufted duck (breeding) 31.2 1.56 0.62 0.31
Raptors
Peregrine: breeding 2.05 0.10 0.04 0.02
Peregrine: non-breeding 0.53 0.03 0.01