Second North American Sea Duck Conference - Patuxent Wildlife ...

SECOND NORTH AMERICAN SEA DUCK CONFERENCE
IS FLIGHT BEHAVIOR OF COMMON EIDER AFFECTED
BY OPERATING WIND TURBINES?
- AN ON-OFF EXPERIMENT
Jesper Larsen and Magella Guillemette
National Environnemental Research Institute, Division of Coastal Zone Ecology, Grenåvej 12, DK-
8410 Rønde, Denmark; jesper.kyed@mail.dk
Offshore wind parks are erected in shallow waters (< 20 m) exactly where sea ducks feed and rest.
We studied the effect of wind turbines on flight behavior of wintering common eiders (Somateria
mollissima) to discriminate the effect of the revolving wind turbine rotors from the standing structures.
The presence of the wind turbines may influence two behavioral decisions: where to fly (flight path)
and whether to land (landing willingness). To address the willingness to land (reacting birds), groups
of decoys were positioned within (100 and 300 m) and outside (100, 300, and 500 m) the wind park.
Flight paths (flying birds) were assigned to one of the five corridors centered on a decoy group using
a laser binocular. The operational state of the wind turbines were manipulated (from a remote control
center) in an alternating manner during ten trials conducted during the morning flights of common
eiders. Irrespective of the operational state of the turbines, the number of flying and reacting birds
was significantly related to corridor location and position of the decoy group with much reduced
activity close to the wind park. However, the operational state of the turbines (on and off) did
neither affect the number of common eiders flying within corridors nor the number of birds reacting
to decoys. These results imply that the avoidance behavior observed was caused by the presence of
the wind turbines structures as such. Following from this, the indifference of common eiders to the
noise (mostly aerodynamic) and movements generated by the operating turbines should increase the
probability of collision during poor visibility conditions (darkness, fog, rain and snow). This was
observed for common eiders during a Scottish study. When visibility is good, on the other hand, the
disturbance caused by the wind turbines structures will decrease the probability of collision.
NOV. 7-11, 2005 ANNAPOLIS, MARYLAND, USA
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