Effects of wind turbines on flight behaviour of wintering common eiders: implications for habitat use and collision risk

• Published in: Journal of Applied Ecology
• Main Authors: LARSEN, JESPER K., GUILLEMETTE, MAGELLA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2007
• Subjects: Kattegat; Somateria mollissima
• Online Access: http://dx.doi.org/10.1111/j.1365-2664.2007.01303.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2664.2007.01303.x; https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2664.2007.01303.x

Summary Wind energy is a fast‐growing renewable energy source and many offshore wind parks will be erected in shallow waters (< 40 m deep) where various coastal bird species are found. The two main issues regarding offshore wind farms and birds are disturbance and collision risk. We studied the effect of wind turbines on the flight behaviour of wintering common eiders Somateria mollissima in order to identify the properties that cause disturbance and the factors that may increase their risk of collision. The study was conducted at Tunø Knob offshore wind park in the Kattegat, Denmark. We attracted birds though the use of decoys located at increasing distances from the wind park. To discriminate between the potential disturbance effect of the standing towers from that of the revolving rotor blades, wind turbines were switched on or off alternately during 10 experimental trials. Common eiders reacted strongly to the presence of wind turbines. The number of flying birds was significantly related to flight corridor location and position of the decoy group. That behavioural reaction was interpreted to be a consequence of their high speed and low‐manoeuvrability flight occurring within the vertical height range of the wind turbines. The number of landing birds also reacted to the position of the decoy group in relation to proximity to the turbines, with the greatest effects observed within the wind park. Such avoidance behaviour might decrease use of otherwise suitable habitat. The movement and noise of rotors affected neither the number of common eiders flying within corridors nor the number of birds reacting to decoys. This suggests that the avoidance behaviour observed was caused by the presence of the structures themselves and that eiders use vision when avoiding human‐made structures. Synthesis and applications . This study has demonstrated that common eiders avoid flying close to or into the Tunø Knob wind park. This behaviour may result in a reduction in habitat availability within and around wind parks, and ...