Birds in southern Öresund in relation to the wind farm at ... - Vattenfall

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The wind farm at Lillgrund consists of 48 turbines placed in eight rows of three to eight turbines in the direction NE – SW, with 300 m between the turbines in one direction and 400 m in the other (Fig. 2). The wind farm is situated about 7 km from the Swedish coast (Fig.1). The total height of the turbines is 115 m up to the top of the wings. The hub height is at 68.5 m above sea level and the rotor diameter is 93 m. For further general information on the wind farm see Vattenfall Vindkraft (2009). Methods Survey methods Censuses of birds in offshore waters can be performed from different platforms, either from boats or from airplanes. Both have advantages and disadvantages. In Danish studies in relation to offshore wind farms (Petersen et al. 2006) and also in other studies, aerial surveys have been used, but boat counts have also been performed in some areas. In the original plans for the monitoring program a combination of local boat counts and aerial surveys covering larger areas were envisioned. In practice the surveys in the first years had to be made by boat only as there were no suitable airplanes available in the region (offshore low level flying must be done by twin-engined aircrafts for security reasons). However, we managed to make aerial surveys in 2006 (plus at two occasions in 2004 to develop methods) before the construction of the wind farm. In this way we also managed to cover the reference area. Aerial surveys were continued after the construction of the wind farm but due to the sometimes difficult flying conditions in winter it was not possible to fly in some periods. The surveys are especially sensitive to wind and turbulence as they implied flying in between the turbines. There were also problems with the boat surveys in 2010 and 2011 due to the ice conditions in Öresund. In these situations it was however possible to fly. According to our experience both survey methods work well in the Lillgrund area but the aerial surveys have the advantage that they cover a much larger area in shorter time. It is however important to use both methods as some species can be difficult to detect and count properly from an aircraft (Nilsson 1975) whereas it for other species is important that large areas can be covered to avoid double-counting. Boat surveys The boat surveys at Lillgrund have followed the standardized methods used in the ESASproject (European Seabird at Sea Team) documented by Komdeur et al. (1992). The method was originally established for larger ships in offshore areas but we have made the surveys from a small boat and adapted the method accordingly. The boat surveys were performed as line transects following a standardized route (Fig. 3) from north of Lillgrund and over Lillgrund and Bredgrund with 2 km between the survey lines except for Bredgrund where this was not possible due to the shallow water. The surveys were normally conducted by two observers, each covering one side of the boat. Some counts 16
had to be made with only one observer (covering just one side). The observation height was about 3 m above the water surface. All birds seen were counted and the position of each observation (bird or flock of birds) was estimated into five distance bands. The following bands were used: A= 0-50 m, B = 50-100 m, C= 100-200 M, D = 200-300 m and E >300 m. Observations were registered on tape or digital recorder with time of observation, species, number, behavior and estimated position. The position of the boat was recorded with a GPS every minute, meaning that a position was recorded about every 170 m with the normal travelling speed (10 km/h). Fig. 3. Map of the southern part of Öresund with the boat survey lines shown in red. Water depths are shown with different grades of blue: 0-3m (darkest), 3-6 m, 6-10 m and 10-20 m (lightest). The turbines at Lillgrund are shown with black dots. Karta över södra Öresund med den standardiserade rutten för båtinventeringarna inritad i rött. Vindkraftverken visas med svarta punkter. De olika blå nyanserna visar områden med olika djup med de fyra djupintervallen 0-3 m (mörkast blått), 3-6 m, 6-10 m och 10-20 m och djupare (ljusast). Bird data were transcribed from tapes or data files after each survey and combined with the position data recorded and stored in the GPS, hence giving all observations a position. The observations were then stored in a data-base. The number of boat surveys undertaken in different months and years is found in Table 1. The low number of boat surveys undertaken during 2007 – 2011 was due to technical problems with the boat and difficult ice conditions during the winter periods. 17
Page 1 and 2: Birds in southern Öresund in relat
Page 3 and 4: Contents Summary 4 Svensk sammanfat
Page 5 and 6: the birds and/or the flocks, the be
Page 7 and 8: Metoder Inventeringarna av rastande
Page 9 and 10: Alfågel (Fig. 14-19) Alfågeln öv
Page 11 and 12: Liksom vid andra inventeringar av r
Page 13 and 14: Introduction Southern Öresund is a
Page 15: Lillgrund is situated in the southe
Page 19 and 20: Fig. 5. Map of the southern part of
Page 21 and 22: Fig. 6 . Map over the wind farm at
Page 23 and 24: transect was divided into 10 km lon
Page 25 and 26: Results Staging and wintering birds
Page 27 and 28: Table.3 Percentage of the total num
Page 29 and 30: Cormorant Phalacrocorax carbo As is
Page 31 and 32: Fig. 10. Summary distribution maps
Page 33 and 34: Overall Jacob’s index (D) for the
Page 35 and 36: Long-tailed Duck Clangula hyemalis
Page 37 and 38: ehind the large variation is that f
Page 41 and 42: Common Eider Somateria mollissima T
Page 47 and 48: Jacobs Index Jacobs Index 1 0,5 0 -
Page 49 and 50: 2500 2000 1500 1000 500 0 MIN MEAN
Page 51 and 52: Fig. 30. Details of Fig. 29 to show
Page 53 and 54: large-scale changes in abundance ar
Page 55 and 56: 600 500 400 300 200 100 0 MIN MEAN
Page 59 and 60: Jacobs Index Jacobs Index 1 0,5 0 -
Page 61 and 62: Lillgrund and the wind farm are sit
Page 63 and 64: The spring migration season, and he
Page 65 and 66: % of all echoes (flocks) 45 40 35 3
Page 67 and 68:
% of all echoes (flocks) 20 15 10 5
Page 69 and 70:
% of all echoes (flocks) 70 60 50 4
Page 71 and 72:
irds given the assumptions used abo
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% of all echoes (flocks) % of all e
Page 75 and 76:
% av alla ekon (flockar) 20 15 10 5
Page 77 and 78:
species, some species being better
Page 79 and 80:
area and from a Dutch farm show tha
Page 81 and 82:
distance from the farm, although mo
Page 83 and 84:
Literature Alerstam, T. 1972. Noctu
Page 85:
Petersen, I. K. & Fox A. D. 2007. C
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Birds in southern Öresund in relation to the wind farm at ... - Vattenfall

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