The Impact of Offshore Wind Farms on Bird Life in Southern Kalmar Sound, Sweden a fi Nal Report Based on Studies 1999–2003
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The Impact of Offshore Wind Farms on Bird Life in Southern Kalmar Sound, Sweden A fi nal report based on studies 1999–2003 Jan Pettersson at the request of the Swedish Energy Agency A reference group collaboration with its principal centre at the Department of Animal Ecology, Lund University, Sweden – 2 – The Impact of Offshore Wind Farms on Bird Life in Southern Kalmar Sound, Sweden A fi nal report based on studies 1999–2003 Jan Pettersson (2005) at the request of the Swedish Energy Agency A reference group collaboration with its principal centre at Ekologiska Institutionen Lunds Universitet Photo and graphics: Jan Pettersson @ JP Fågelvind 2005 ISBN 91-631-6878-2 – 3 – Contents Summary ....................................................................................................... 4 Conclusions .......................................................................................................................................................6 1 Introduction ............................................................................................7 1.1 Background ............................................................................................................................................7 1.2 Basic issues .............................................................................................................................................8 1.3 Reference Group ...................................................................................................................................8 1.4 Research areas .......................................................................................................................................9 2 The waterfowl migration in Kalmar Sound ......................................... 10 2.1 Total extent of waterfowl migration .................................................................................................10 2.2 Migration and extent of predominant species .................................................................................10 3 Methods ................................................................................................14 3.1 Project planning and different stages ...............................................................................................14 3.2 Monitoring of migration fl ights .........................................................................................................14 3.3 Surveys of staging waterfowl .............................................................................................................21 3.4 Positioning staging waterfowl fl ocks .................................................................................................22 3.5 Meteorological data ............................................................................................................................23 3.6 Quality control and statistical analyses ..............................................................................................24 4 Results ...................................................................................................25 4.1 Field observations of spring migration ..............................................................................................25 4.2 Field observations of the infl uence of wind on spring migration ...................................................32 4.3 Radar observations of spring migration ............................................................................................36 4.4 Field observations of autumn migration ...........................................................................................50 4.5 Observations of autumn migration ....................................................................................................57 4.6 Trackings of autumn migrant waterfowl fl ocks near the wind turbines .........................................66 4.7 A migrating waterfowl fl ock in collision with the wind turbines ....................................................82 4.8 Staging and wintering waterfowl in southern Kalmar Sound .........................................................84 4.9 Other birds in southern Kalmar Sound and at the wind farms ........................................................86 5 Discussion and conclusions .................................................................101 5.1 Scope of the study .............................................................................................................................101 5.2 How do the wind turbines affect the migration corridor of Eider in the Sound? ........................101 5.3 How do the wind turbines affect the choice of migrating corridor of other waterfowl in the Sound? ..........................................................................................................................................102 5.4 How do waterfowl fl ocks fl y in the immediate vicinity of the wind turbines? .............................102 5.5 How is the nocturnal migration of waterfowl in the Sound affected? .........................................103 5.6 How is the waterfowl migration in the Sound affected in fog and mist in daytime? ..................103 5.7 What impact do the wind turbines have on the length of the fl ight path? ................................104 5.8 What is the collision risk factor for migrant waterfowl? ................................................................104 5.9 What impact do the wind turbines have on staging and wintering waterfowl? .........................109 5.10 How do rare and red- listed species fl y near the wind turbines? .................................................110 5.11 The percentage of migrant waterfowl affected by the offshore wind turbines. .......................110 6 Acknowledgements ............................................................................112 7 References ...........................................................................................113 8 Appendix .............................................................................................115 – 4 – The Utgrunden lighthouse has been used as an observation site from the open platform at a height of 27 m and from the side of the platform that gave shelter at the time. – 5 – The impact of offshore wind farms on bird life in Kalmar Sound 1999–2003 Summary An ornithological study was carried out over four spring extends their fl ight path by 1.2–2.4 km, or for a few fl ocks and four autumn seasons from 1999–2003 on one and a half up to 2.9 km. This extension of the fl ight path is 0.2–0.4 per million migrating waterfowl in southern Kalmar Sound in cent of the total migration distance of the waterfowl from the Sweden. The study was conducted in connection with two breeding area to the wintering area and vice versa, which groups of offshore wind farms constructed at Utgrunden can be expressed as a certain increase in energy expenditure and Yttre Stengrund, with seven and fi ve wind turbines for the birds’ migration. respectively. Night and mist The migration patterns of waterfowl through the Sound Radar monitoring of fl ocks showed that waterfowl migra- and the fl ocks’ reactions on encountering the wind turbines tion in fog and mist is rather limited overall. About 5–6 were studied and documented during periods of good vis- per cent of the total number of birds passing in spring and ibility by direct visual observation and by following the autumn migrate in such conditions, and this corresponds fl ocks with an optical rangefi nder. During periods of poor very closely to the amount of time (5–9 per cent of the time visibility (such as fog or mist, or during the night), and studied) in which there is fog and mist. These fl ocks avoid similarly during the day with good visibility, radar fi lms the wind turbines in the same way as those that migrate from military surveillance radar were analysed in order to in good visibility. The nocturnal waterfowl migration in follow the fl ocks’ fl ight paths and to document their reac- Kalmar Sound is extensive and makes up 22–27 per cent tions and behaviour when faced with wind turbines in their of the total. The nocturnal migratory fl ocks fl y at a greater migratory path. distance from land than those that migrate by day. The Wind farms waterfowl fl ocks seem to react to the wind turbines from a In the middle of southern Kalmar Sound – which is 20 considerable distance at night too, about 500–1000 metres km wide at this point –seven wind turbines were erected before they reach them. The fl ocks that come closer to the at Utgrunden in autumn 2000. The fi ve wind turbines at turbines at night (both in the autumn and spring) fl y in a Yttre Stengrund, situated roughly 3 km from the shoreline, curve to avoid the turbines in the same way as those that were erected in the summer of 2001 and are about 20–30 migrate in the daytime. km south of Utgrunden. Rare species Spring and autumn migration Only a few of the rare, red-listed species observed, or birds The study includes a total of 859 000 spring migrating of prey in the area, seem to fl y into the immediate area of waterfowl and 674000 autumn migrants. Up to 95% of the the wind farms during migration. About 4 per cent of the spring migrating waterfowl in the area consist of Eider, this somewhat rarer species observed migrating in the spring fl y fi gure being 56% of the autumn migration in Kalmar Sound. into the immediate area of the wind turbines at Utgrunden Other species consist mostly of ducks, geese and Cormo- and 5 per cent in the