Impact on breeding birds of a semi-offshore island-based windmill park in Åland, Northern Baltic Sea

Antti Tanskanen

doi:10.34080/os.v22.22593

Abstract

Breeding bird populations were monitored at a windmill park on Båtskär in southern Åland archipelago 2006–2011. The area is in the outer archipelago and consists of four islands holding six windmills. The operation of windmills started during fall 2007. An environmental impact assessment for the area was done in 2002. The area holds 850–1050 pairs of breeding birds annually. Two species had significantly decreasing trends, namely herring gull Larus argentatus (annual decrease 6.9 pairs, p=0.003) and lesser black-backed gull Larus fuscus fuscus (annual decrease 2.8 pairs, p=0.004). The reason for the decline of the herring gull population is unlikely to be related to the windmill park. However, the close proximity of a windmill to the breeding colony of lesser black-backed gull has most likely contributed to their decline. Some species like swallow Hirundo rustica, house martin Delichon urbicum and auks Alcidae have benefitted of the construction of the windmill park and utilize new small environments created by the construction.

Highlights

During the last decade, wind power has been built increasingly on land, shores and large islands, with a current trend to build more offshore parks
Some species like swallow Hirundo rustica, house martin Delichon urbicum and auks Alcidae have benefitted of the construction of the windmill park and utilize new small environments created by the construction
Effects on coastal breeding terns have been studied in Belgium (Everaert & Stienen 2007), but studies of breeding birds on small islands having large (>1 MW) wind turbines are lacking

Summary

Introduction

Wind power has been built increasingly on land, shores and large islands, with a current trend to build more offshore parks. Semioffshore building on small islands and islets is rare; only few areas in the world have such possibilities, as are found around Åland. The effects of wind power on birds have been studied mainly in North America and Europe, and these studies have mainly dealt with the impact of small units having a nominal capacity of less than. Effects on coastal breeding terns have been studied in Belgium (Everaert & Stienen 2007), but studies of breeding birds on small islands having large (>1 MW) wind turbines are lacking. In the Baltic Sea area studies from Sweden (Petterson 2005) and Denmark (Petersen et al 2006) describe results from offshore parks

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