Dodging the blades: new insights into three-dimensional space use of offshore wind farms by lesser black-backed gulls Larus fuscus

Lesser Black-backed Gull - Edmund Fellowes

Author(s): Thaxter, C.B., Ross-Smith, V.H., Bouten, W., Masden, E.A., Clark, N.A., Conway, G.J., Barber, L., Clewley, G.D. & Burton, N.H.K.

Published: 2 January 2018

Journal: Marine Ecology Progress Series Volume: 587

Digital Identifier No. (DOI): 10.3354/meps12415

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Initial findings suggest that Lesser Black-backed Gulls in north-west England fly within wind farms, but may avoid wind turbines once there.

Offshore wind farms may affect birds in many ways, such as stopping them moving between places, or restricting access to areas where they feed. Collision risk is a key concern for seabirds, yet there has been little study to date of the use of wind farms by birds from known breeding colonies. This study, led by BTO, provides a first look at the movements of Lesser Black-backed Gulls at a colony in north-west England and their interaction with five operational offshore wind farms. The birds were tracked with GPS tags which recorded location, speed and height. Out of the 24 birds tracked, 15 visited wind farms, and in total spent 1.3% of their time there. A detailed look at the movements of two birds that visited wind farms most often, showed that their flight heights were greater within wind farms than outside, particularly during the day, potentially placing them at greater risk of collision. However, within wind farms, their use of the zone swept by the rotor blades was significantly less than expected. Although preliminary, these results suggest that Lesser Black-backed Gulls at this site may not avoid wind farms, but could avoid individual wind turbines once inside the wind farms. Further work is now being conducted to verify these patterns, which will be important in improving our understanding of the likely collision risk for seabirds.

Abstract

GPS telemetry is improving our understanding of the way animals interact with their environment. Recent research has used this technology to assess the impact of offshore wind farms (OWFs) on seabirds, but few studies have collected fine-scale data from birds flying within OWFs. We use GPS telemetry to investigate movements of lesser black-backed gulls Larus fuscus in relation to OWFs from a protected site with an active breeding colony. Individual birds varied considerably in their use of OWFs; 15 out of 24 birds visited them, and time spent in these areas was 1.3% of time budgets across all birds. Two birds, for which the most data was collected, frequently entered OWFs and flew at turbine blade height; however, their overlap with the spherical 3-dimensional rotor swept volume was significantly lower than a random distribution. Although preliminary, these tracking data suggest a lack of a macro-scale (wind farm-scale) avoidance for L. fuscus but a potential meso-scale (within wind farm-scale) avoidance of turbines. Such data are therefore important in improving our understanding of the implications of OWFs for seabirds.

Notes

This study was funded by the Department of Energy and Climate Change (DECC, now DBEIS) Offshore Energy Strategic Environmental Assessment Research Programme, and the Marine Renewable Energy and the Environment (MaREE) project.

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