The occurrence and breeding success of Red-throated Loon Gavia stellata and Black-throated Loon Gavia arctica in the vicinity of land-based wind turbines

Abstract

For loons (Gaviidae), there is good evidence of long-term displacement around offshore wind farms on wintering grounds, but studies of any impact on either Red-throated Loon Gavia stellata or Black-throated Loon Gavia arctica from land-based wind turbines are scarce. Current recommendations, based on best available knowledge, are not to locate wind turbines closer than 1 km from breeding sites, and for Red-throated Loon also to avoid locating turbines on the flight routes between breeding pools and foraging waters. These recommendations sometimes necessitate substantial modifications during the planning of a wind farm. To study their relevance, pairwise comparisons of the occupation of breeding lakes and breeding success before and after the start of operation were done. For Red-throated Loon, impaired breeding performance was indicated, and ideally the recommendations should be extended not to locate wind turbines within 2 km from breeding sites. For Black-throated Loon, there were no indications of impact, but the results are not entirely conclusive as they rest on data from a small number of breeding sites. Thus, a cautionary approach should be applied. We need further knowledge about impact related future large-scale wind farms and long-term impact over at least one generation after start of operation.