Environmental Engineering Reference
In-Depth Information
Results and Analysis of Eagle Studies
from the Bluff Point and Studland Bay
Wind Farms 2002-2012
Cindy Hull , Chris Sims , Elizabeth Stark , and Stuart Muir
Abstract
The Tasmanian wedge-tailed eagle (WTE,
Aquila audax fl eayi
) and the
white-bellied sea-eagle (WBSE,
Haliaeetus leucogaster
) are present on the Bluff
Point (37 Vestas V66 turbines) and Studland Bay (25 Vestas V90 turbines) Wind
Farms in north-west Tasmania, Australia. These species have been intensively studied
since the commencement of operations in 2002 and 2007, respectively, as part of
compliance monitoring. Monitoring has included documenting collisions with tur-
bines, breeding success surveys, and movement and behaviour studies. Additional
investigations (outside regulatory requirements) have also been conducted, including
targeted studies and trials of collision mitigation techniques. Both species of eagle
have continued to use the sites during construction and operation of the wind farms.
The average collision rates for WTE were 1.54 and 0.95 per year, and for WBSE 0.36
and 0 per year at Bluff Point and Studland Bay, respectively (calculated up to October
2012). These are below maximum rates estimated in collision risk modeling which
formed part of the information for the assessment of the wind farms. The collision rate
for WTE was constant across years, although there was some evidence the rate could
be declining at Studland Bay. Analyses could not be conducted on WBSE due to small
sample sizes. Seasonal and other temporal patterns were tested for in the collision
data, but all evidence supported the theory that the strikes were independent and
random in time, with no support found for some proposed theories about why eagles
collide with turbines. A spatial analysis of collisions was not possible, again due to
small sample sizes. Eagles continued to breed at the sites, with at least the same level
of success as nests outside the wind farms. The observational studies provided useful
data about how eagles interacted with turbines at these sites. These data were used to
calculate turbine avoidance rates and to assess how rates changed with development
of the wind farm and when turbines were operational or not.
Keywords
Eagles Wind farms Collisions Monitoring Mitigation
